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1 <?xml version="1.0" encoding="ISO-8859-1"?><!-- $Id$
2 Universal Worker Service WD
3 Note that this file should be xhtml with div to mark sections so that it can be updated with xslt.
4 Paul Harrison -->
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7 <html xmlns="http://www.w3.org/1999/xhtml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="en" lang="en" xsi:schemalocation="http://www.w3.org/1999/xhtml http://www.w3.org/2002/08/xhtml/xhtml1-transitional.xsd"><head xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" profile="http://www.w3.org/1999/xhtml/vocab"><title>Universal Worker Service Specification</title><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"/><meta name="Title" content="IVOA WG Internal Draft"/><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"/><meta name="author" content="Paul Harrison, paul.harrison@manchester.ac.uk"/><meta name="maintainedBy" content="Paul Harrison, paul.harrison@manchester.ac.uk"/><link href="http://www.ivoa.net/misc/ivoa_a.css" rel="stylesheet" type="text/css"/><link rel="stylesheet" href="http://www.ivoa.net/misc/ivoa_pr.css" type="text/css"/><link href="./ivoadoc/XMLPrint.css" rel="stylesheet" type="text/css"/><link href="./ivoadoc/ivoa-extras.css" rel="stylesheet" type="text/css"/></head><body><div class="head">
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9 <img src="http://www.ivoa.net/pub/images/IVOA_wb_300.jpg" height="169" width="300"/></td><td style="padding: 0cm;" rowspan="1" colspan="1">
10 <p><b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);"> I</span></i></b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">nternational</span></i></p>
11 <p><b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">    V</span></i></b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">irtual</span></i></p>
12 <p><b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">    O</span></i></b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">bservatory</span></i></p>
13 <p><b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">A</span></i></b><i><span style="font-size: 14pt; color: rgb(0, 90, 156);">lliance</span><span style="color: black;">
14 </span></i></p></td></tr></tbody></table>
15 <h1>Universal Worker Service Pattern<br/>
16 Version 1.0</h1>
17 <h2>IVOA Proposed Recommendation 2010-02-10</h2>
18 <dl><dt>Working Group:</dt><dd><a href="http://www.ivoa.net/twiki/bin/view/IVOA/IvoaGridAndWebServices" shape="rect">http://www.ivoa.net/twiki/bin/view/IVOA/IvoaGridAndWebServices</a></dd><dt><b>This version:</b></dt><dd><a href="http://www.ivoa.net/Documents/PR/GWS/PR-UWS-1.0-20100210.html" shape="rect">http://www.ivoa.net/Documents/PR/GWS/PR-UWS-1.0-20100210.html</a></dd><dt><b>Latest version:</b></dt><dd><a href="http://www.ivoa.net/Documents/UWS/" shape="rect">http://www.ivoa.net/Documents/UWS/</a></dd><dt><b>Previous version(s):</b></dt><dd> Internal Working Draft
19 v0.1, 2005-01-24
20 <br/>
21 Internal Working Draft
22 v0.2, 2006-05-11 <br/>
23 Internal
24 Working Draft v0.3, 2007-04-26<br/>
25 Internal
26 Working Draft v0.4, 2008-05-10<br/>
27 Internal Working Draft v0.5, 2008-10-08<br/>
28 Internal Working Draft v0.9, 2009-10-08<br/>
29 Public Working Draft v1.0, 2009-08-27<br/>
30 Proposed Recommendation v1.0, 2009-09-09</dd><dt> <br/>
31 </dt><dt> </dt><dt><b>Author(s):</b></dt><dd> P.
32 Harrison, G. Rixon</dd></dl>
33
34 <h2>Abstract</h2>
35 <p>The Universal Worker Service (UWS) pattern
36 defines how to manage asynchronous execution of jobs on a
37 service. Any application of the pattern defines a family of related
38 services with a common service contract. Possible uses of the pattern are also described.</p>
39 <h2> Status of This Document</h2>
40 <p>This document is produced by
41 the GWS-WG. The first release of this document was on 2005-01-24
42 within the working group.</p>
43 <p>This is an IVOA Proposed Recommendation made available for public review.
44 Comments on this document should be posted at the RFC page <a href="http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/UWSV1RFC" shape="rect">http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/UWSV1RFC</a> or can be sent to the Grid and Web Services Working Group via <a href="mailto:grid@ivoa.net" shape="rect">grid@ivoa.net</a>.</p>
45 <p> <em>A list of </em><span style="background: transparent"><a href="http://www.ivoa.net/Documents/" shape="rect"><i>current
46 IVOA Recommendations and other technical documents</i></a></span><em> can be found at http://www.ivoa.net/Documents/.</em></p>
47 <p>The words "MUST", "SHALL", "SHOULD", "MAY", "RECOMMENDED", and "OPTIONAL" (in upper or lower case) used in this document are to be interpreted as described in IETF standard, RFC 2119 <cite>
48 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:rfc2119">std:rfc2119</a>]
49 </cite>.</p>
50 <h2 class="prologue-heading-western">Acknowledgements</h2>
51 <p>The need for the UWS pattern was
52 inspired by AstroGrid&#8217;s Common Execution Architecture and
53 particularly by discussions with Noel Winstanley. The ideas about
54 statefulness are distilled from debates in the Global Grid Forum in
55 respect of the Open Grid Services Infrastructure that was the
56 fore-runner of Web Services Resource Framework. The REST binding came
57 initially from suggestions by Norman Gray.</p>
58 </div><h2>Contents</h2><div><?toc?><div xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" id="toc" class="toc"><ul><li><a href="#Introduction"><span class="secnum">1. </span>Introduction (informative)</a><ul><li><a href="#SynchronousStateless"><span class="secnum">1.1. </span> Synchronous, stateless services</a></li><li><a href="#AsynchronousServices"><span class="secnum">1.2. </span> Asynchronous and stateful services</a></li><li><a href="#JDL"><span class="secnum">1.3. </span> Job description language, service contracts and universality</a></li></ul></li><li><a href="#UWSpattern"><span class="secnum">2. </span> Universal Worker Service Pattern (normative)</a><ul><li><a href="#UWSObjects"><span class="secnum">2.1. </span> Objects within a UWS</a><ul><li><a href="#Joblist"><span class="secnum">2.1.1. </span>
59 Job list </a></li><li><a href="#Job"><span class="secnum">2.1.2. </span>Job</a></li><li><a href="#ExecutionPhase"><span class="secnum">2.1.3. </span> Execution Phase</a></li><li><a href="#ExecutionDuration"><span class="secnum">2.1.4. </span> Execution Duration</a></li><li><a href="#DestructionTime"><span class="secnum">2.1.5. </span> Destruction Time</a></li><li><a href="#Quote"><span class="secnum">2.1.6. </span>Quote</a></li><li><a href="#Error"><span class="secnum">2.1.7. </span>Error</a></li><li><a href="#Error2"><span class="secnum">2.1.8. </span>Owner</a></li><li><a href="#Error3"><span class="secnum">2.1.9. </span>RunId</a></li><li><a href="#ResultsList"><span class="secnum">2.1.10. </span>Results List</a></li><li><a href="#ResultsList2"><span class="secnum">2.1.11. </span>Parameter List</a></li></ul></li><li><a href="#RESTbinding"><span class="secnum">2.2. </span>The REST Binding</a><ul><li><a href="#d1e834"><span class="secnum">2.2.1. </span>Resources and URIs</a></li><li><a href="#d1e603"><span class="secnum">2.2.2. </span>Representations of resources</a><ul><li><a href="#d1e1030"><span class="secnum">2.2.2.1. </span>Job List</a></li><li><a href="#d1e1040"><span class="secnum">2.2.2.2. </span>Job</a></li><li><a href="#d1e1344"><span class="secnum">2.2.2.3. </span>Results List</a></li><li><a href="#d1e1353"><span class="secnum">2.2.2.4. </span>Parameters List</a></li><li><a href="#d1e1556"><span class="secnum">2.2.2.5. </span> Error</a></li></ul></li><li><a href="#jobcontrol"><span class="secnum">2.2.3. </span>State changing requests</a><ul><li><a href="#d1e1375"><span class="secnum">2.2.3.1. </span>Creating a Job</a></li><li><a href="#d1e1390"><span class="secnum">2.2.3.2. </span>Deleting a Job</a></li><li><a href="#d1e1402"><span class="secnum">2.2.3.3. </span>Changing the Destruction
60 Time</a></li><li><a href="#d1e1420"><span class="secnum">2.2.3.4. </span>Changing the Execution
61 Duration</a></li><li><a href="#d1e1439"><span class="secnum">2.2.3.5. </span> Starting a Job</a></li><li><a href="#d1e1448"><span class="secnum">2.2.3.6. </span>Aborting a Job</a></li></ul></li><li><a href="#d1e708"><span class="secnum">2.2.4. </span>Message pattern</a></li></ul></li></ul></li><li><a href="#security"><span class="secnum">3. </span>Security Considerations (normative)</a></li><li><a href="#ApplicationsOfUWS"><span class="secnum">4. </span> Applications of UWS (informative)</a><ul><li><a href="#Imageservice"><span class="secnum">4.1. </span> Image service with data staging</a></li><li><a href="#ADQLservice"><span class="secnum">4.2. </span> ADQL service with cursor</a></li><li><a href="#ParameterizedApplications"><span class="secnum">4.3. </span> Parameterized applications</a></li></ul></li><li><a href="#SynchronousService"><span class="secnum">5. </span> Implementing a Synchronous Service on top of UWS (informative)</a></li><li><a href="#Updates"><span class="secnum">Appendix A. </span> Updates from previous versions</a><ul><li><a href="#d1e1112"><span class="secnum">Appendix A.1. </span>At Version 0.5</a></li><li><a href="#d1e1775"><span class="secnum">Appendix A.2. </span>At Version 1.0</a></li></ul></li><li><a href="#UWSSchema"><span class="secnum">Appendix B. </span> UWS Schema</a></li></ul></div></div><div class="body">
62 <div class="section"><h2><a name="Introduction" id="Introduction" shape="rect"/><span class="secnum">1. </span>Introduction (informative)</h2>
63 <p>The Universal Worker Service (UWS)
64 pattern defines how to build <i>asynchronous</i>, <i>stateful</i>, <i>job-oriented</i> services<i> </i>(the italicized terms are defined
65 in sub-sections of this introduction). It does so in a way that
66 allows for wide-scale reuse of software and support from software
67 toolkits.</p>
68 <p>Section <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#UWSpattern">2. </a></span>
69 of this document describes
70 the pattern and lists the aspects that are common to all its
71 applications. Any such application would involve a service contract
72 that embodies the pattern and fixes the issues left undefined in the
73 pattern itself (see section <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#JDL">1.3. </a></span>). The contract might include the XML schemata which form a "job description language" or JDL for the application, or simply a description of the input parameters for the service which are conveyed via typical HTML form encodings. It is intended that each such contract
74 cover a family of related applications, such that the implementations
75 may be widely reused.</p>
76 <p>Section <a href="#security" shape="rect">3</a> outlines several possible
77 applications of the pattern. These use-cases may be expanded into
78 full IVOA standards that are siblings of the current document.</p>
79 <p>Section <a class="xref" href="#ApplicationsOfUWS" shape="rect">4</a> describes the preferred
80 method of creating a synchronous facade to a UWS system.</p>
81 <div class="section"><h3><a name="SynchronousStateless" id="SynchronousStateless" shape="rect"/><span class="secnum">1.1. </span> Synchronous, stateless services</h3>
82 <p>Simple web services are <i>synchronous</i> and <i>stateless</i>. Synchronous means that the client waits for
83 each request to be fulfilled; if the client disconnects from the
84 service then the activity is abandoned. <i>Stateless</i> means that
85 the service does not remember results of a previous activity (or, at
86 least, the client cannot ask the service about them).</p>
87 <p>Synchronous, stateless services work
88 well when two criteria apply.</p>
89 <ol><li>
90 <p>The length of each activity is
91 less than the &#8220;attention span&#8221; of the connection.</p>
92 </li><li>
93 <p>The results of each activity are
94 compact enough to be easily passed back to the client via the
95 connection on which the request was made (and possibly pushed back
96 to the service as parameters of the next activity).</p>
97 </li></ol>
98 <p>There are various limits to the
99 attention span.</p>
100 <ul><li>
101 <p>HTTP assumes that the start of a
102 reply quickly follows its request, even if the body of the reply
103 takes a long time to stream. If the service takes too long to
104 compute the results and to start the reply, then HTTP times out and
105 the request is lost.</p>
106 </li><li>
107 <p>A client runs on a computer which
108 will not stay on-line indefinitely.</p>
109 </li><li>
110 <p>A network with finite
111 reliability will eventually break communications during an activity.</p>
112 </li><li>
113 <p>A service is sometimes shut down
114 for maintenance.</p>
115 </li></ul>
116 <p>Synchronous, stateless services, in
117 short, do not scale well. The following examples illustrate situations in the VO in which synchronous, stateless services are inadequate.</p>
118 <ol><li>
119 <p>An ADQL <cite>
120 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:adql">std:adql</a>]
121 </cite> service gives access
122 to a large object-catalogue. Most queries run in less than a minute,
123 but some legitimate queries involve a full-table traverse and take
124 hours or days. The service needs to run these special cases in a
125 low-priority queue.</p>
126 </li><li>
127 <p>An object-finding service runs
128 the SExtractor <cite>
129 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#sextractor">sextractor</a>]
130 </cite> application on a list of images. Normally, the list
131 is short and the request is quickly satisfied. Occasionally, a list
132 of 10,000 images is sent in the expectation that the work will be
133 finished over the weekend.</p>
134 </li><li>
135 <p>A cone-search <cite>
136 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:scs">std:scs</a>]
137 </cite> request on a
138 rich catalogue raises 10,000,000 rows of results, but the client is
139 connected via a slow link and cannot read all the results in a
140 reasonable time. The client needs the service to send the results
141 into storage over a faster link. This could mean sending them to
142 VOSpace <cite>
143 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:vospace">std:vospace</a>]
144 </cite>, or simply holding them temporarily at the service until the user can
145 retrieve them on a fast link. UWS provides a pattern for doing the latter.</p>
146 </li><li>
147 <p>An ADQL service allows users to
148 save query results into new tables such that they can be the target
149 of later queries. However, space is limited and the results tables
150 can only be kept for a short time. The client and service negotiate
151 the lifetime of the results tables.</p>
152 </li><li>
153 <p>A service performs image
154 stacking on a list of fields. Each field can be processed by a
155 synchronous service but the list is long and the user wants to
156 retrieve the results of the early fields before the last fields are
157 processed.</p>
158 </li></ol>
159 </div>
160 <div class="section"><h3><a name="AsynchronousServices" id="AsynchronousServices" shape="rect"/><span class="secnum">1.2. </span> Asynchronous and stateful services</h3>
161 <p>Services can be made to scale better
162 by making them <i>asynchronous</i> and <i>stateful</i>. Asynchronous
163 means that a client makes two or more separate requests to the
164 service in the course of one activity, and that the client and
165 service may be disconnected, possibly for days or more, in between
166 those requests. Stateful means that the service stores state
167 information about the activity and the client addresses requests to
168 this state.</p>
169 <p>Web services that are asynchronous
170 are almost always stateful. Most of the special extra arrangements for
171 asynchronous activities are actually managing the state of the
172 activity.</p>
173 <p>There is an important class of
174 stateful services where the state is peculiar to one job or session
175 and the job is &#8220;owned&#8221; by one user. These, for the purpose of
176 this document, are called <i>job-oriented</i> services. There are
177 stateful services that are not job-oriented (e.g. a service managing
178 a shared, client-writeable DB table), but UWS does not apply to
179 these.</p>
180 <p>For the purpose of this discussion,
181 let the term <i>job</i> refer to the work specified by the JDL
182 instructions and the term <i>resource</i> refer to the state of the
183 job as recorded by the service. Both have a finite duration. The <i>lifetime</i> of the resource &#8211; i.e. the time from inception
184 until the service forgets the state &#8211; is generally finite and must
185 be at least as long the duration of the job.</p>
186 </div>
187 <div class="section"><h3><a name="JDL" id="JDL" shape="rect"/><span class="secnum">1.3. </span> Job description language, service contracts and universality</h3>
188 <p>Consider the web-service operation
189 that starts off a job. This operation must express what is to be done
190 in the activity: it must carry parameters in some form.</p>
191 <p>The parameters may be expressed as a
192 list. For example, a cone search service takes a list of three parameters:
193 RA, DEC, RADIUS. Alternatively, the parameters may be arranged as an
194 XML document (e.g. ADQL, CEA <cite>
195 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#harrison05">harrison05</a>]
196 </cite>). The rules for setting and arranging
197 the parameters for a job are called the<i> Job-Description Language </i>(JDL).</p>
198 <p>The combination of the UWS pattern, a
199 JDL and details of the job state visible to the client defines a
200 service contract. Changing the JDL changes the contract. Thus, it is not
201 meaningful to &#8220;implement UWS&#8221; in isolation; any implementation
202 standard must specify the rest of the contract.</p>
203 <p>If the JDL is very general, a single
204 service-contract can be reused for many kinds of service. AstroGrid&#8217;s
205 CEA<cite>
206 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#harrison05">harrison05</a>]
207 </cite>exploits this: one JDL covers all services offering parameterized
208 applications and even ADQL services. In the limit, a
209 sufficiently-general JDL turns a specialized worker service into a
210 universal worker service.</p>
211 </div>
212 </div>
213 <div class="section"><h2><a name="UWSpattern" id="UWSpattern" shape="rect"/><span class="secnum">2. </span> Universal Worker Service Pattern (normative)</h2>
214 <div class="section"><h3><a name="UWSObjects" id="UWSObjects" shape="rect"/><span class="secnum">2.1. </span> Objects within a UWS</h3>
215 <p>A UWS consists logically of a set of
216 objects that may be read and written to in order to control jobs. The objects are represented by elements within the XML schema detailed in <a class="xref" href="#UWSSchema" shape="rect">Appendix B</a>. In a REST binding, these objects are addressed as distinct web-resources each with its own URI. </p>
217 <p> The following sub-sections explain the semantics of the objects. The
218 UML diagram below shows the relationships more succinctly.</p>
219 <p><img src="Class_Diagram__UWS__UWSObjects.png" alt="UWS Objects Class Diagram" width="460" height="390" id="graphics2"/></p>
220 <div class="section"><h4><a name="Joblist" id="Joblist" shape="rect"/><span class="secnum">2.1.1. </span>
221 Job list </h4>
222 <p>The Job List is the outermost object:
223 it contains all the other objects in the UWS. The immediate children
224 of the job list are Job objects (see next sub-section).</p>
225 <p>The job list may be read to find the
226 extant jobs.</p>
227 <p>The job list may be updated to add a
228 new job.</p>
229 <p>The job list itself does not allow
230 jobs to be deleted. Instead, when a job is destroyed by an action on
231 its job object, then the list updates itself accordingly.</p>
232 </div>
233 <div class="section"><h4><a name="Job" id="Job" shape="rect"/><span class="secnum">2.1.2. </span>Job</h4>
234 <p>A Job object contains the state of
235 one job. The state is a collection of other objects. Each Job
236 contains:</p>
237 <ul><li>
238 <p>Exactly one Execution Phase.</p>
239 </li><li>
240 <p>Exactly one Execution Duration.</p>
241 </li><li>
242 <p>Exactly one Deletion Time</p>
243 </li><li>
244 <p>Exactly one Quote.</p>
245 </li><li>
246 <p>Exactly one Results List.</p>
247 </li><li>
248 <p>Zero or one Error.</p>
249 </li></ul>
250 </div>
251 <div class="section"><h4><a name="ExecutionPhase" id="ExecutionPhase" shape="rect"/><span class="secnum">2.1.3. </span> Execution Phase</h4>
252 <p>The job is treated as a state machine
253 with the Execution Phase naming the state. The phases are:</p>
254 <ul><li>
255 <p>PENDING: the job is accepted by
256 the service but not yet committed for execution by the client. In
257 this state, the job quote can be read and evaluated. This is the
258 state into which a job enters when it is first created.</p>
259 </li><li>
260 <p>QUEUED: the job is committed for
261 execution by the client but the service has not yet assigned it to a
262 processor. No Results are produced in this phase.</p>
263 </li><li>
264 <p>EXECUTING: the job has been
265 assigned to a processor. Results may be produced at any time during
266 this phase.</p>
267 </li><li>
268 <p>COMPLETED: the execution of the
269 job is over. The Results may be collected.</p>
270 </li><li>
271 <p>ERROR: the job failed to
272 complete. No further work will be done nor Results produced. Results
273 may be unavailable or available but invalid; either way the Results
274 should not be trusted.</p>
275 </li><li>
276 <p>ABORTED: the job has been
277 manually aborted by the user, or the system has aborted the job due
278 to lack of or overuse of resources.</p>
279 </li><li><p>UNKNOWN: The job is in an unknown state.</p></li><li><p>HELD: The job is HELD pending execution and
280 will not automatically be executed (cf, pending)</p></li><li><p>SUSPENDED: The job has been suspended by the system during execution. This might be because of temporary lack of resource. The UWS will automatically resume the job into the EXECUTING phase without any intervention when resource becomes available.</p></li></ul>
281 <p>A successful job will normally progress through the PENDING, QUEUED, EXECUTING, COMPLETED phases in that order. At any time before the COMPLETED phase a job may either be ABORTED or may suffer an ERROR. If the UWS reports an UNKNOWN phase, then all the client can do is requery the phase until a known phase is reported. A UWS may place a job in a HELD phase on receipt of a PHASE=RUN request if for some reason the job cannot be immediately queued - in this case it is the responsibility of the client to request PHASE=RUN again at some later time.</p>
282 <p><img src="UWSStates.png" alt="UWS state diagram" width="487" height="332"/></p>
283
284 </div>
285 <div class="section"><h4><a name="ExecutionDuration" id="ExecutionDuration" shape="rect"/><span class="secnum">2.1.4. </span> Execution Duration</h4>
286 <p>An Execution Duration object defines
287 the duration for which a job shall run. This represents the
288 &#8220;computation time&#8221; that a job is to be allowed, although because
289 a specific measure of CPU time may not be available in all
290 environments, this duration is defined in real clock seconds. An
291 execution duration of 0 implies unlimited execution duration.</p>
292 <p>When the execution duration has been
293 exceeded the service should automatically abort the job, which has the
294 same effect as when a manual &#8220;Abort&#8221; is requested.</p>
295 <p>Specifically, when a job is aborted:</p>
296 <ul><li>
297 <p>if the job is still executing,
298 the execution is aborted.</p>
299 </li><li>
300 <p>any previously generated results
301 of the job are retained.</p>
302 </li></ul>
303 <p>When a job is created, the service
304 sets the initial execution duration. The client may write to an
305 Execution Duration to try to change the job's cpu time allocation.
306 The service may forbid changes, or may set limits on the allowed
307 execution duration.</p>
308 </div>
309 <div class="section"><h4><a name="DestructionTime" id="DestructionTime" shape="rect"/><span class="secnum">2.1.5. </span> Destruction Time</h4>
310 <p>The Destruction Time object
311 represents the instant when the job shall be destroyed. The
312 Destruction Time is an absolute time.</p>
313 <p>Destroying a job implies:</p>
314 <ul><li>
315 <p>if the job is still executing,
316 the execution is aborted.</p>
317 </li><li>
318 <p>any results from the job are
319 destroyed and storage reclaimed.</p>
320 </li><li>
321 <p>the service forgets that
322 the job existed.</p>
323 </li></ul>
324 <p>The Destruction Time should be viewed as
325 a measure of the amount of time that a service is prepared to
326 allocate storage for a job &#8211; typically this will be a longer
327 duration that the amount of CPU time that a service would allocate.</p>
328 <p>When a job is created the service
329 sets the initial Destruction Time. The client may write to the
330 Destruction Time to try to change the life expectancy of the job. The
331 service may forbid changes, or may set limits on the allowed
332 destruction time.</p>
333 </div>
334 <div class="section"><h4><a name="Quote" id="Quote" shape="rect"/><span class="secnum">2.1.6. </span>Quote</h4>
335 <p>A Quote object predicts when the job
336 is likely to complete. The intention is that a client creates the
337 same job on several services, compares the quotes and then accepts
338 the best quote. From the server perspective it is possible to indicate that a job will not be run by specifying a Quote that is greater than the Destruction time.</p>
339 <p>Quoting for a computational job is
340 notoriously difficult. A UWS implementation must always provide a
341 quote object, in order that the two-phase committal of jobs be
342 uniform across all UWS, but it may supply a &#8220;don't know&#8221; answer
343 for the completion time, indicated by a negative value or an XML nil element in an XML representation of the quote object.</p>
344 </div>
345 <div class="section"><h4><a name="Error" id="Error" shape="rect"/><span class="secnum">2.1.7. </span>Error</h4>
346 <p>The error object gives a human-readable error message for the underlying job. This object
347 is intended to be a detailed error message, and consequently might be
348 a large piece of text such as a stack trace. When there is an error
349 running a job, a summary of the error should also be given using the
350 optional errorSummary element of the Job element.</p>
351 </div>
352 <div class="section"><h4><a name="Error" id="Error2" shape="rect"/><span class="secnum">2.1.8. </span>Owner</h4>
353 <p>The owner object represents the identifier for the creator of the job. This object will not exist for all invocations of a UWS conformant protocol, but only in cases where the access to the service is authenticated as discussed more thoroughly in section
354 <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#security">3. </a></span>. </p>
355 </div>
356 <div class="section"><h4><a name="Error" id="Error3" shape="rect"/><span class="secnum">2.1.9. </span>RunId</h4>
357 <p>The RunId object represents an identifier that the job creator uses to identify the job. Note that this is distinct from the Job Identifier that the UWS system itself assigns to each job. The UWS system should do no parsing or processing of the RunId, but merely pass back the value (if it exists) as it was passed to the UWS at job creation time. In particular it may be the case that multiple jobs have the same RunId, as this is a mechanism by which the calling process can identify jobs that belong to a particular group. The exact mechanism of setting the RunId is not specified here, but will be part of the specification of the protocol using the UWS pattern.</p>
358 </div>
359 <div class="section"><h4><a name="ResultsList" id="ResultsList" shape="rect"/><span class="secnum">2.1.10. </span>Results List</h4>
360 <p>The Results List object is a
361 container for formal results of the job. Its children may be any
362 objects resulting from the computation that may be fetched from the
363 service when the job has completed.</p>
364 <p>Reading the Results List itself
365 enumerates the available or expected result objects.</p>
366 <p>The children of the Results List may
367 be read but not updated or deleted. The client cannot add anything
368 to the Results List.</p>
369 </div>
370 <div class="section"><h4><a name="ResultsList" id="ResultsList2" shape="rect"/><span class="secnum">2.1.11. </span>Parameter List</h4>
371 <p>The Parameter List is an
372 enumeration of the Job parameters. The form that the parameters take will depend on the JDL of the implementing service - for instance if the JDL is expressed as a single XML document, then there would be a single "parameter" that was that XML document. For services where the JDL consists of a list of name/value pairs (typical of the standard IVOA "simple" access protocols), then these would naturally be expressed in the parameter list. Each parameter value may be expressed either directly as the content of the parameter element, or the value expressed "by reference", where there returned parameter value is a URL that points to the location where the actual parameter value is stored.</p>
373 <p>A particular implementation of UWS may choose to allow the parameters to be updated after the initial job creation step, before the Phase is set to the executing state. It is up to the individual implementation to specify exactly how these parameters may be updated, but good practice (in the REST binding) would be to choose one of the following options.</p>
374 <ol><li>HTTP POST an <i>application/x-www-form-urlencoded</i><b> </b>parameter name, value pair to either
375 <ol><li>/{jobs}/{job-id)</li><li>/{jobs}/{job-id)/parameters</li></ol>
376 </li><li>HTTP PUT the parameter value to /{jobs}/{job-id)/parameters/(parameter-name)</li></ol>
377 <p>Additionally a particular implementation of UWS may allow the "job control" parameters (see section <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#jobcontrol">2.2.3. </a></span>) to be specified as part of the JDL. If doing this then the implementation must document the possibility and must use the standard parameter names (which may cause a conflict with parameters in the JDL, which is one of the reasons for the two stage job creation pattern of UWS).</p>
378 </div>
379 </div>
380 <div class="section"><h3><a name="RESTbinding" id="RESTbinding" shape="rect"/><span class="secnum">2.2. </span>The REST Binding</h3>
381 <p>In order to create a usable service the objects discussed in the section above must be exposed in a particular interface which can be addressed over a particular transport mechanism - this combination is known as a "binding". In this first version of the UWS pattern only a REST (Representational State
382 Transfer) style binding <cite>
383 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#fielding00">fielding00</a>]
384 </cite>is presented, however, future versions of this document will add other bindings such as SOAP. <cite>
385 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:soap">std:soap</a>]
386 </cite>. It should be noted that REST is based on HTTP <cite>
387 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:http">std:http</a>]
388 </cite> and as such the REST binding inherits standard HTTP behaviours. In particular it should be noted that the REST binding makes use of HTTP status codes to control the behaviour of the client, especially the "300" class redirection codes to ensure that the client requests particular resources after state changing operations. If for some reason there is a failure in the underlying UWS machinery then a 500 "internal server error" status should be returned. However individual job failures are indicated by setting the appropriate parts of the job representation to error statuses and a request for the individual job object representation at /(jobs)/(jobid) should have a normal 200 status code response.</p>
389
390 <div class="section"><h4><a name="d1e834" id="d1e834" shape="rect"/><span class="secnum">2.2.1. </span>Resources and URIs</h4>
391 <p>In a REST (Representational State
392 Transfer) binding of UWS, each of the objects defined above is
393 available as a web resource with its own URI. These URIs must form a
394 hierarchy as shown in the table below:</p>
395 <table border="1" cellpadding="2" cellspacing="0"><tr><th scope="col" rowspan="1" colspan="1">URI</th><th scope="col" rowspan="1" colspan="1">Description</th><th scope="col" rowspan="1" colspan="1">Representation</th></tr><tr><td rowspan="1" colspan="1">/{jobs}</td><td rowspan="1" colspan="1">the Job List</td><td rowspan="1" colspan="1"> the <span class="xmlelement">&lt;jobs&gt;</span> element in the UWS schema</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)</td><td rowspan="1" colspan="1">a Job</td><td rowspan="1" colspan="1"><p>the <span class="xmlelement">&lt;job&gt;</span> element in the UWS schema<br/>
396 </p></td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/phase</td><td rowspan="1" colspan="1"> the Phase of job
397 (job-id)</td><td rowspan="1" colspan="1">one of the fixed strings</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/executionduration</td><td rowspan="1" colspan="1">the
398 maximum execution duration of (job-id)</td><td rowspan="1" colspan="1">Integer number of seconds</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/destruction</td><td rowspan="1" colspan="1"> the
399 destruction instant for (job-id)</td><td rowspan="1" colspan="1"><cite>
400 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:iso8601">std:iso8601</a>]
401 </cite></td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/error</td><td rowspan="1" colspan="1">any error
402 message associated with (job-id)</td><td rowspan="1" colspan="1">any representation appropriate to the implementing service</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/quote </td><td rowspan="1" colspan="1">the Quote for
403 (job-id)</td><td rowspan="1" colspan="1">Integer number of seconds</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/results</td><td rowspan="1" colspan="1">any parameters for the job
404 (job-id)</td><td rowspan="1" colspan="1">the <span class="xmlelement">&lt;results&gt;</span> element in the UWS schema</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/parameters</td><td rowspan="1" colspan="1">any parameters for the job
405 (job-id)</td><td rowspan="1" colspan="1">the <span class="xmlelement">&lt;parameters&gt;</span> element in the UWS schema</td></tr><tr><td rowspan="1" colspan="1">/{jobs}/(job-id)/owner</td><td rowspan="1" colspan="1">the owner of the job (job-id)</td><td rowspan="1" colspan="1">an appropriate identifier as discussed in
406 <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#security">3. </a></span></td></tr></table>
407 <p>The service implementer is free to
408 choose the names given in parentheses above, i.e. the root of the URI tree, and the form that the job identifier takes (though note that it should be a legal URI path element) - the other names are part
409 of the UWS standard.</p>
410 <p>The URI for the Job List, in its
411 absolute form is the root URI for the whole UWS. This URI should be
412 given as the access URL in the UWS registration.</p>
413 </div>
414 <div class="section"><h4><a name="d1e603" id="d1e603" shape="rect"/><span class="secnum">2.2.2. </span>Representations of resources</h4>
415 <p>Each of the UWS objects is mapped to a resource URI as detailed in the table above, and for each URI, a HTTP GET
416 fetches a representation of that resource. In general where an object is a container for other objects (Job List, Job, Result List, Parameter List) then an XML representation of the object should be returned, otherwise for simple atomic types (Quote, Execution Duration etc.) a textual (mime type "text/plain") representation should be returned. The XML schema for the various objects described above is
417 detailed in
418 <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#UWSSchema">Appendix B. </a></span>
419 of this specification. This schema is the definitive description of the exact form of the XML returned by a UWS and must not vary between implementations.</p>
420 <p>HTTP allows multiple representations
421 of a resource distinguished by their MIME types and selected by the
422 HTTP "Accept" headers of a GET request. A UWS implementation can exploit this to support both web
423 browsers and rich clients in the same tree of resources. Although the default behaviour is to return XML, a UWS could return HTML or XHTML to
424 clients that accept these types. These clients are assumed to be web
425 browsers and the UWS is generating its own user interface. The HTML
426 interface generated should allow full control of the UWS via the use
427 of HTML forms and appropriate links.</p>
428 <p>Clients which are assumed to be part
429 of remote applications that drive UWS without showing the details to
430 their users should accept only "application/xml,text/plain". A UWS must therefore
431 return XML representations of the resources in preference to the HTML representation. A technique that may be used to always return XML that modern browsers can transform on the client-side to HTML is via the <span class="xmlelement">&lt;?xml-stylesheet ?&gt;</span> processing instruction, which can be used to point to a suitable XSL resource to perform the transformation. </p>
432 <p> More detail for some of the UWS objects is provided below.</p>
433 <div class="section"><h4><a name="d1e1030" id="d1e1030" shape="rect"/><span class="secnum">2.2.2.1. </span>Job List</h4>
434 <p>The representation of the Job List is
435 a list of links to extant jobs. The list may be empty if the UWS is
436 idle.</p>
437 </div>
438 <div class="section"><h4><a name="d1e1040" id="d1e1040" shape="rect"/><span class="secnum">2.2.2.2. </span>Job</h4>
439 <p>The representation of a Job is as specified by the <span class="xmlelement">&lt;job&gt;</span> element in the UWS schema as detailed in <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#UWSSchema">Appendix B. </a></span>
440 an example or such a job instance is shown below</p>
441 <div><?incxml href="../UWSJobInstance.xml" ?><div xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="viewxml"><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:job</span> <span class="attribute-name">xsi:schemaLocation</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0 UWS.xsd "</span> <span class="attribute-name">xmlns:xml</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/XML/1998/namespace"</span> <span class="attribute-name">xmlns:uws</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0"</span> <span class="attribute-name">xmlns:xlink</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/1999/xlink"</span> <span class="attribute-name">xmlns:xsi</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/2001/XMLSchema-instance"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:jobId</span><span class="markup">&gt;</span><span class="text">cea-agdevel.jb.man.ac.uk-130.88.24.18-1242749568029-508182314</span><span class="markup">&lt;/</span><span class="end-tag">uws:jobId</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:ownerId</span> <span class="attribute-name">xsi:nil</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:phase</span><span class="markup">&gt;</span><span class="text">COMPLETED</span><span class="markup">&lt;/</span><span class="end-tag">uws:phase</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:startTime</span><span class="markup">&gt;</span><span class="text">2009-05-19T17:12:48.038+01:00</span><span class="markup">&lt;/</span><span class="end-tag">uws:startTime</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:endTime</span><span class="markup">&gt;</span><span class="text">2009-05-19T17:12:48.041+01:00</span><span class="markup">&lt;/</span><span class="end-tag">uws:endTime</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:executionDuration</span><span class="markup">&gt;</span><span class="text">86400</span><span class="markup">&lt;/</span><span class="end-tag">uws:executionDuration</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:destruction</span><span class="markup">&gt;</span><span class="text">2009-05-29T17:12:48.035+01:00</span><span class="markup">&lt;/</span><span class="end-tag">uws:destruction</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:parameters</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:parameter</span> <span class="attribute-name">id</span><span class="markup">=</span><span class="attribute-value">"scaleFactor"</span><span class="markup">&gt;</span><span class="text">1.8</span><span class="markup">&lt;/</span><span class="end-tag">uws:parameter</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:parameter</span> <span class="attribute-name">id</span><span class="markup">=</span><span class="attribute-value">"image"</span> <span class="attribute-name">byReference</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><span class="text">
442 http://myserver.org/uws/jobs/jobid123/param/image</span><span class="markup">&lt;/</span><span class="end-tag">uws:parameter</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:parameters</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:results</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:result</span> <span class="attribute-name">id</span><span class="markup">=</span><span class="attribute-value">"correctedImage"</span> <span class="attribute-name">xlink:href</span><span class="markup">=</span><span class="attribute-value">"http://myserver.org/uws/jobs/jobid123/result/image"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:results</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:errorSummary</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"transient"</span> <span class="attribute-name">hasDetail</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">uws:message</span><span class="markup">&gt;</span><span class="text">we have problem</span><span class="markup">&lt;/</span><span class="end-tag">uws:message</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:errorSummary</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">uws:jobInfo</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">any</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xml</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">thatyouwant</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xml</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">any</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:jobInfo</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">uws:job</span><span class="markup">&gt;</span></div></div></div>
443 <p>The <span class="xmlelement">&lt;job&gt;</span> element has placeholders of all of the standard UWS objects, and in addition there is a <span class="xmlelement">&lt;uws:jobinfo&gt;</span> element which can be used by implementations to include any extra information within the job description.</p>
444 </div>
445 <div class="section"><h4><a name="d1e1344" id="d1e1344" shape="rect"/><span class="secnum">2.2.2.3. </span>Results List</h4>
446 <p>The representation of a Results List
447 is a list of links to the resources representing the results. These
448 resources may have any URI and any MIME type. A sensible default for
449 their URIs is to make them children of /{jobs}/(job-id)/results, but
450 this is not required. It may sometimes be easier for a service
451 implementer to point to a resource on some web server separate from
452 that running the UWS. Therefore, a client must always parse the
453 Results List to find the results. Where a protocol applying UWS
454 specifies standard results it must do so by naming those results and fixing the result URIs, however the UWS must still return a valid Results List at /{jobs}/(job-id)/results.</p>
455 </div>
456 <div class="section"><h4><a name="d1e1353" id="d1e1353" shape="rect"/><span class="secnum">2.2.2.4. </span>Parameters List</h4>
457 The representation of the parameters list is a list of
458 <span class="xmlelement">&lt;parameter&gt;</span> elements. Each of these elements can either represent the value of the parameter directly, where the content of the element is a textual representation of the parameter, or in the case where the parameter value cannot be represented legally within XML (e.g. the parameter is a binary type such as a FITS file) then the content of the parameter is a URL to the parameter value - to indicate this case the attribute byReference is set to "true".</div>
459 <div class="section"><h4><a name="d1e1556" id="d1e1556" shape="rect"/><span class="secnum">2.2.2.5. </span> Error</h4>
460 <p>When an error occurs in a job the UWS must signal this at a minimum by setting the PHASE to error. In addition the <span class="xmlelement">&lt;errorSummary&gt;</span> element, giving a brief summary of the error, should be included within the <span class="xmlelement">&lt;job&gt;</span> element. The UWS may include a more detailed error message for example an execution log or stack trace by providing such a resource at the /(jobs}/(jobid)/error URI. It is the responsibility of the implementing service to specify the form that such an error message may take.</p>
461 </div>
462 </div>
463 <div class="section"><h4><a name="jobcontrol" id="jobcontrol" shape="rect"/><span class="secnum">2.2.3. </span>State changing requests</h4>
464 <p>Certain of the UWS' resources accept
465 HTTP POST and DELETE messages to change the state of the service &#8211;
466 This is the fundamental way that a client controls the execution of a
467 job. In most of the cases where a job sub-object is set the response
468 will have a http 303 &#8220;See other&#8221; status and a Location header
469 that points back to the main job summary obtained at the <span style="font-weight: medium">/{jobs}/(job-id)
470 URI. The job summary contains the values of (or links to) all the UWS objects
471 within the returned XML (or XHTML). This mode of operation was chosen
472 (as opposed to returning only the sub-object being altered) as it
473 makes for a more natural user interface &#8211; especially in the case of
474 the XHMTL interface. A client that wants to obtain only the value of
475 a particular sub-object can at any time request that sub-object with
476 a HTTP GET.</span></p>
477 <div class="section"><h4><a name="d1e1375" id="d1e1375" shape="rect"/><span class="secnum">2.2.3.1. </span>Creating a Job</h4>
478 <p>POSTing a request to the Job List
479 creates a new job (unless the service rejects the request). The
480 response when a job is accepted must have code 303 &#8220;See other&#8221;
481 and the Location header of the response must point to the created
482 job.</p>
483 <p>This initial POST will in most cases
484 carry parameters for the protocol that is using the UWS pattern, as
485 detailed in <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#ApplicationsOfUWS">4. </a></span>
486 .In addition for the initial post may contain job control parameters if allowed by the implementing protocol (i.e. if UWS job control parameter names do not clash with the implementing protocol parameters). One use of this facility might be to have the job placed into a potentially running state by adding PHASE=RUN to the job creation step.</p>
487 </div>
488 <div class="section"><h4><a name="d1e1390" id="d1e1390" shape="rect"/><span class="secnum">2.2.3.2. </span>Deleting a Job</h4>
489 <p>Sending a HTTP DELETE to a Job
490 resource destroys that job, with the meaning noted in the definition
491 of the Job object, above. No other resource of the UWS may be
492 directly deleted by the client. The response to this request must
493 have code 303 &#8220;See other&#8221; and the Location header of the response
494 must point to the Job List at the /{jobs} URI.</p>
495 <p>Posting a request with a parameter
496 ACTION=DELETE to the Job also destroys the job, the response being as
497 for a deletion. This action supports web browsers which typically
498 cannot send DELETE requests.</p>
499 </div>
500 <div class="section"><h4><a name="d1e1402" id="d1e1402" shape="rect"/><span class="secnum">2.2.3.3. </span>Changing the Destruction
501 Time</h4>
502 <p>The Destruction Time may be changed
503 by POSTing to /{jobs}/(job-id)/destruction. In this case, the body
504 of the posted request is of type <i>application/x-www-form-urlencoded</i><b> </b><span style="font-weight: medium">and
505 contains the parameter named DESTRUCTION whose value is the new
506 destruction time in ISO8601 format; i.e. this request is what an HTML
507 form sends.</span></p>
508 <p style="font-weight: medium">The
509 response to this request must have code 303 &#8220;See other&#8221; and the
510 Location header of the response must point to the /{jobs}/(job-id)
511 URI so that the client receives the value that the service has
512 actually set the Destruction Time to within the Job summary response. The service may override the requested Destruction Time and substitute a value of its choosing e.g. a job owner may have reached his storage quota and so the service only allows further data to be stored for shorter times than requested.</p>
513 </div>
514 <div class="section"><h4><a name="d1e1420" id="d1e1420" shape="rect"/><span class="secnum">2.2.3.4. </span>Changing the Execution
515 Duration</h4>
516 <p>The Execution Duration may be changed
517 by POSTing to /{jobs}/(job-id)/executionduration. In this case, the body
518 of the posted request is of type <i>application/x-www-form-urlencoded</i><b> </b><span style="font-weight: medium">and
519 contains the parameter named EXECUTIONDURATION whose value is the new
520 executionduration in seconds.</span></p>
521 <p style="font-weight: medium">The
522 response to this request must have code 303 &#8220;See other&#8221; and the
523 Location header of the response must point to the
524 /{jobs}/(job-id) so that the client receives the value that the
525 service has actually set the Execution Duration to. The service may to override the request and substitute a value of its choosing</p>
526 </div>
527 <div class="section"><h4><a name="d1e1439" id="d1e1439" shape="rect"/><span class="secnum">2.2.3.5. </span> Starting a Job</h4>
528 <p style="font-weight: medium">A
529 job may be started by POSTing to the /{jobs}/(job-id)/phase URI. The
530 POST contains a single parameter PHASE=RUN which instructs the UWS to
531 attempt to start the job. The response to this request must have code
532 303 &#8220;See other&#8221; and the Location header of the response must
533 point to the /{jobs}/(job-id) URI so that the client receives the
534 phase that the job has been set to. Typically a UWS will put a job
535 into a QUEUED state on receipt of this command, but depending on how
536 busy the server is, the job might be put almost immediately (and
537 without client intervention) into an EXECUTING state.</p>
538 </div>
539 <div class="section"><h4><a name="d1e1448" id="d1e1448" shape="rect"/><span class="secnum">2.2.3.6. </span>Aborting a Job</h4>
540 <p style="font-weight: medium">A
541 job may be aborted by POSTing to the /{jobs}/(job-id)/phase URI. The
542 POST contains a single parameter PHASE=ABORT which instructs the UWS
543 to attempt to abort the job. Aborting a job has the effect of stopping a job executing, but the resources associated with a job remain intact. The response to this request must have
544 code 303 &#8220;See other&#8221; and the Location header of the response must
545 point to the /{jobs}/(job-id) URI so that the client receives the
546 phase that the job has been set to.</p>
547 </div>
548 </div>
549 <div class="section"><h4><a name="d1e708" id="d1e708" shape="rect"/><span class="secnum">2.2.4. </span>Message pattern</h4>
550 <p>The REST binding results in the
551 message pattern shown in figure 2.</p>
552 <p><i>Illustration 2:
553 Typical calling sequence for the REST binding of UWS</i></p>
554 <p><img src="Sequence_Diagram__UWS__Rest_Message_Pattern__Rest_Message_Pattern__Rest_Message_Pattern.png" width="100%" id="graphics3" alt="rest message pattern"/></p>
555 <br style="clear: both;"/>
556 </div>
557 </div>
558 </div>
559 <div class="section"><h2><a name="security" id="security" shape="rect"/><span class="secnum">3. </span>Security Considerations (normative)</h2>
560 <p>A UWS should follow IVOA standards for security <cite>
561 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:ssoauth">std:ssoauth</a>]
562 </cite> if it is desired that a non-public UWS be created. It is possible to imagine many different authorization policies that might be employed in an authenticated UWS, where particular groups of users have different permissions to create and view different types of jobs. A full discussion of such authorization policies is beyond the scope of this document, but a UWS should behave as described in section <span xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="xref"><a href="#RESTbinding">2.2. </a></span>
563 for any individual authenticated user, although it is clear that a user without sufficient privileges might only obtain a restricted list of jobs within the joblist at /{jobs}. Any attempt to retrieve a job for which the user does not have sufficient privilege should result in a 403 Forbidden HTTP status being returned.</p>
564 <p>When an authentication mechanism is used in the UWS then the implementation should set the owner object to the identity obtained by the authentication. </p>
565 </div>
566 <div class="section"><h2><a name="ApplicationsOfUWS" id="ApplicationsOfUWS" shape="rect"/><span class="secnum">4. </span> Applications of UWS (informative)</h2>
567 <p>The UWS pattern leaves undefined two
568 essential parts of the service contract: the content that must be
569 posted to create a job; and the pattern of results made available by
570 a completed job. An application of UWS completes a service contract
571 by defining these matters.</p>
572 <p>There follow some use cases applying
573 the UWS pattern. The descriptions are neither formal nor complete.
574 The intention is to show a range of ways that the pattern can be
575 applied without burdening the reader with the level of detail needed
576 for a standard implementation.</p>
577 <p>Any of these cases could be worked up
578 into a full IVOA standard by formalizing the description, adding
579 detail and generally making the specification more
580 exact and complete.</p>
581 <div class="section"><h3><a name="Imageservice" id="Imageservice" shape="rect"/><span class="secnum">4.1. </span> Image service with data staging</h3>
582 <p>Consider a service that computes
583 images from archive data. The computation takes significant time, so
584 the service is asynchronous. The service keeps the computed images in
585 its own storage until the user downloads them; this is essentially
586 the model of SIAP <cite>
587 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:siap">std:siap</a>]
588 </cite>.</p>
589 <p>The asynchronous image-service is a
590 logical extension of a synchronous SIA service. Therefore it uses the
591 REST binding of UWS.</p>
592 <p>The parameters for posting a new job
593 are as for SIAP 1.0:</p>
594 <ul><li>
595 <p>POS, the position on the sky to
596 be searched.</p>
597 </li><li>
598 <p>SIZE, the size of the search
599 box.</p>
600 </li><li>
601 <p>FORMAT: the type of images to be
602 computed.</p>
603 </li></ul>
604 <p>Particular implementations are free
605 to add extra parameters.</p>
606 <p>These parameters are posted in a
607 document of type <i>application/x-www-form-urlencoded</i><span style="font-style: normal">:
608 i.e. they can be sent from an HTML form.</span></p>
609 <p style="font-style: normal">The
610 images generated by the job are accessible as unnamed results. Each
611 image has its own URI and can be downloaded over HTTP at any time
612 until the destruction time of the job. The URIs for the images may be
613 discovered from the Results List in the normal UWS way.</p>
614 <p style="font-style: normal">SIAP
615 1.0 produces, for each query, a table of metadata describing the
616 images. The asynchronous image-service produces a table to the same
617 schema as a named result, called &#8220;table&#8221;.</p>
618 <p><span style="font-style: normal">Image
619 results are added to the results list, and to the &#8220;table&#8221; result,
620 as they are generated. Hence, a client that polls the service can
621 discover, download and use some of the images before the job is
622 finished. </span>If the client is satisfied with
623 these early images, the client can cancel the rest of the job by
624 destroying the job. However, destroying the job deletes the cached
625 images so the client has to download them <i>first</i>.</p>
626 </div>
627 <div class="section"><h3><a name="ADQLservice" id="ADQLservice" shape="rect"/><span class="secnum">4.2. </span> ADQL service with cursor</h3>
628 <p>ADQL [1] can serve as a JDL. Consider
629 an ADQL service that supports long-running queries as asynchronous
630 operations. In general, the results of the query may be a large set
631 of data. They may be too large to download comfortably. We might like
632 to cache these results on the service and to operate a cursor,
633 drawing down from the resource a few rows of the table at a time.</p>
634 <p>The parameters of a job are as
635 follows:</p>
636 <ul><li>
637 <p>ADQL: the query text</p>
638 </li><li>
639 <p>FORMAT: the format for the
640 results</p>
641 </li></ul>
642 <p>These parameters are posted in a
643 document of type <i>application/x-www-form-urlencoded</i><span style="font-style: normal">:
644 i.e. they can be sent from an HTML form.</span></p>
645 <p style="font-style: normal">A
646 successful query generates the following, named results.</p>
647 <ul><li>
648 <p style="font-style: normal"><i>table</i>:
649 the whole result set as one file resource.</p>
650 </li><li>
651 <p style="font-style: normal"><i>header</i>:
652 the metadata for the output table.</p>
653 </li><li>
654 <p style="font-style: normal"><i>cursor</i>:
655 a selection of rows of output.</p>
656 </li></ul>
657 <p>The <i>cursor</i> result is
658 parameterized by the query parameters FIRST and LAST in the query
659 string of its URI: these parameters state the index of the first and
660 last row to be returned; e.g.</p>
661 <p> http://whatever.org/adlqService/results/cursor?FIRST=1&amp;LAST=100</p>
662 <p>If the parameters are missing, the
663 service decides which rows to return.</p>
664 </div>
665 <div class="section"><h3><a name="ParameterizedApplications" id="ParameterizedApplications" shape="rect"/><span class="secnum">4.3. </span> Parameterized applications</h3>
666 <p>There is a class of applications on
667 which a job may be defined by a list of simple parameters. &#8220;Simple&#8221;
668 here means unstructured: a scalar value such as a number, a string of
669 text or a boolean value. If the parameters are allowed to be name files,
670 so that structured data are passed indirectly, then the class of
671 applications is very large indeed. Almost any non-interactive
672 application can be driven in this way.</p>
673 <p>Turning each application of choice
674 into a service (with or without UWS semantics) would be onerous.
675 However, if the application&#8217;s interface is entirely characterized,
676 through the JDL, in terms of typed input and output parameters, then
677 one service contract will work for all the applications and a single
678 implementation of the contract can be reused for all cases.</p>
679 <p>AstroGrid&#8217;s Common Execution
680 Architecture (CEA) <cite>
681 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#harrison05">harrison05</a>]
682 </cite> works in this way. It has just one service
683 contract for all applications (including ADQL services; the ADQL
684 query is passed in the list of parameters). It has four
685 implementations, one for each of the possible interfaces between the
686 service and a kind of job (jobs can be implemented with Java classes,
687 command-line applications, HTTP-get services or JDBC databases). CEA
688 also specifies stateful, asynchronous services and makes use of
689 VOSpace.</p>
690 <p>Consider a CEA reworked to use the
691 UWS pattern for consistency with other (future) IVOA standards. Call
692 it CEA v2 to distinguish it from CEA v1 as currently maintained by
693 AstroGrid. For this example, consider the particular kind of CEA
694 service that runs applications supplied as executable binaries.</p>
695 <p>A binary application-server has a
696 library of applications co-located with its service and defined in
697 the service configuration set by the service provider. It does not
698 accept code from the client for local execution.</p>
699 <p>The JDL in CEA v2 is similar to that
700 in CEA v1 It is a formal, XML vocabulary for expressing choice
701 of application and parameter lists <cite>
702 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:vocea">std:vocea</a>]
703 </cite>. Parameters may be inputs or
704 outputs of the job.</p>
705 <p>To start a job, a document in this
706 JDL is posted to the UWS. The document is sent in its native
707 MIME-type, application/xml, so this is not an interface that can be
708 driven directly from an HTML form, although it can be driven from the
709 emerging XForms technology<cite>
710 [<a xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" href="#std:xform">std:xform</a>]
711 </cite>.</p>
712 <p>The results of the job depend on the
713 choice of application. They are all named results and the names and
714 types are defined in the definition of the application. That
715 application-definition is registered, so the client knows before
716 running the job what results to expect.</p>
717 <p>CEA input-parameters may be indirect:
718 i.e. they may refer to data in on-line storage. In this case, the JDL
719 document contains the URIs for those data objects Alternatively, the
720 parameters may be direct, in which case the JDL contains the actual
721 value of the parameters.</p>
722 <p>Similarly, CEA results may be made
723 indirect. In this case, the results are named as parameters in the
724 JDL where the values are the URIs to which the results are delivered.
725 The application server can then stream the results to the specified
726 destination as they become available and need not cache them locally.
727 If a job result is indirect, then the server can choose whether or
728 not to keep a local copy. If it chooses not to cache locally, then
729 the result URI in the UWS is set to the external location named in
730 the URI.</p>
731 </div>
732 </div>
733 <div class="section"><h2><a name="SynchronousService" id="SynchronousService" shape="rect"/><span class="secnum">5. </span> Implementing a Synchronous Service on top of UWS (informative)</h2>
734 <p>Whilst the provision of synchronous
735 services is not one of the design aims of the UWS pattern, there is
736 clearly a desire in second generation IVOA services still to allow a
737 simple synchronous calling pattern to be available to simple clients.
738 What follows is a recommended recipe for putting a synchronous facade
739 on UWS;</p>
740 <p>It is assumed that the core of the
741 service does provide a true UWS compliant set of endpoints rooted at
742 /async (equivalent to the /{jobs} endpoint in the nomenclature used
743 above). The desired synchronous service is to be rooted at /sync.</p>
744 <ol><li>
745 <p>The job is started by either a
746 GET (for compatibility with existing IVOA standards) or a POST
747 (preferably) of form encoded parameters to the /sync endpoint.</p>
748 </li><li>
749 <p>Internally the service creates a
750 job in the standard UWS system with the given parameters and sets
751 the PHASE to RUN, noting the returned job identifier which we will
752 call {job-id}. The /sync endpoint then responds with a STATUS 303
753 (redirection) response to the URL /sync/{job-id}.</p>
754 </li><li>
755 <p>The /sync/{job-id} endpoint then
756 blocks until it detects that the underlying job has finished at
757 which point it responds with a STATUS 303 (redirection) to the
758 /{jobs}/{job-id}/results/mainresult URL, where &#8220;mainresult&#8221; is
759 the name of the primary result of the job.</p>
760 </li></ol>
761 <p>In this way the service appears to be
762 a synchronous to the original client &#8211; assuming it obeys standard
763 HTTP redirection semantics, so a simple client like a web browser
764 could obtain the result with a single &#8220;click&#8221;. At the same time a
765 more sophisticated, UWS aware, client could control the same job from
766 the standard /{jobs} endpoint &#8211; indeed if the synchronous call
767 timed out for some reason, then it would be possible for the original
768 client to retrieve the results by looking at the /{jobs}/{job-id} URL
769 tree, because it could make the association of the job-Id from the
770 URL it receives in step 2 above.</p>
771 <p>The purely synchronous client is
772 restricted compared with the full UWS pattern in that there can only
773 be one result directly returned to the client, as noted in stage 3
774 above. This is usually not a problem for compatibility with existing
775 version 1.0 DAL services as they typically return a single VOTable
776 containing references to the desired data.</p>
777 </div>
778
779 <div class="appendices"><h2><a name="Appendices" id="Appendices" shape="rect"/>Appendices</h2>
780
781 <div class="section"><h2><a name="Updates" id="Updates" shape="rect"/><span class="secnum">Appendix A. </span> Updates from previous versions</h2>
782 <div class="section"><h3><a name="d1e1112" id="d1e1112" shape="rect"/><span class="secnum">Appendix A.1. </span>At Version 0.5</h3>
783 <ul><li>
784 <p>changed the POST parameter names
785 to be the same as the resource paths.</p>
786 </li><li>
787 <p>added synchronous section.</p>
788 </li><li>
789 <p>updated SOAP binding section</p>
790 </li></ul>
791 </div>
792 <div class="section"><h3><a name="d1e1775" id="d1e1775" shape="rect"/><span class="secnum">Appendix A.2. </span>At Version 1.0</h3>
793 <ul><li>Removed all SOAP binding - deferred to later version.</li><li>Added parameterList</li><li>Added ownerId and jobId as subsidiary job object</li></ul>
794 </div>
795 </div>
796
797 <div class="section"><h2><a name="UWSSchema" id="UWSSchema" shape="rect"/><span class="secnum">Appendix B. </span> UWS Schema</h2>
798 <p>Note that this schema can be found on-line at <a href="http://www.ivoa.net/xml/UWS/v1.0" shape="rect">http://www.ivoa.net/xml/UWS/v1.0</a> (i.e. the target namespace
799 can also be used as a URL for the schema.) This location should
800 represent the definitive source, the schema is reproduced below only for
801 completeness of this document.</p>
802 <div><?incxml href="../UWS.xsd"?><div xmlns:h="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" class="viewxml"><div class="comment">&lt;!-- $Revision$ $Date$ $HeadURL$ --&gt;</div><div class="comment">&lt;!-- UWS schema - Paul Harrison May 2008 --&gt;</div><div class="comment">&lt;!--
803 $Log: UWS.xsd,v $
804 Revision 1.1 2009/06/15 15:30:32 pah
805 made some of the global element defintions for job subobjects just local again
806 added runid, ownerid
807 added ParamList
808 changed some element names to be consistent with the uris
809 Revision 1.6 2008/10/01 11:54:02 pah fix up cvs
810 header Revision 1.5 2008/09/25 00:22:35 pah change termination
811 time to execution duration
812 --&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:schema</span> <span class="attribute-name">targetNamespace</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0"</span> <span class="attribute-name">elementFormDefault</span><span class="markup">=</span><span class="attribute-value">"qualified"</span> <span class="attribute-name">attributeFormDefault</span><span class="markup">=</span><span class="attribute-value">"unqualified"</span> <span class="attribute-name">xmlns:xml</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/XML/1998/namespace"</span> <span class="attribute-name">xmlns:xs</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/2001/XMLSchema"</span> <span class="attribute-name">xmlns:uws</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/UWS/v1.0"</span> <span class="attribute-name">xmlns:xlink</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/1999/xlink"</span><span class="markup">&gt;</span><div class="comment">&lt;!--
813 &lt;xs:import namespace="http://www.w3.org/1999/xlink"
814 schemaLocation="../../../stc/STC/v1.30/XLINK.xsd" /&gt;
815 --&gt;</div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:import</span> <span class="attribute-name">namespace</span><span class="markup">=</span><span class="attribute-value">"http://www.w3.org/1999/xlink"</span> <span class="attribute-name">schemaLocation</span><span class="markup">=</span><span class="attribute-value">"http://www.ivoa.net/xml/Xlink/xlink.xsd"</span><span class="markup">/&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ShortJobDescription"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"phase"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ExecutionPhase"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the execution phase - returned at
816 /(jobs)/(jobid)/phase</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"id"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:JobIdentifier"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:reference"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"reference"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">standard xlink references
817 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"xlink:type"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"optional"</span> <span class="attribute-name">default</span><span class="markup">=</span><span class="attribute-value">"simple"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"xlink:href"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"optional"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attributeGroup</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:simpleType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ExecutionPhase"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> Enumeration of possible phases of job
818 execution</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:restriction</span> <span class="attribute-name">base</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"PENDING"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The first phase a job is entered into
819 - this is where a job is being set up but no request
820 to run has occurred.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"QUEUED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> An job has been accepted for execution
821 but is waiting in a queue</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"EXECUTING"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">An job is running</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"COMPLETED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> An job has completed successfully
822 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"ERROR"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> Some form of error has occurred
823 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"UNKNOWN"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job is in an unknown state.
824 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"HELD"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job is HELD pending execution and
825 will not automatically be executed - can occur after a PHASE=RUN request has been made (cf PENDING).
826 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"SUSPENDED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job has been suspended by the
827 system during execution</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"ABORTED"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The job has been aborted, either by
828 user request or by the server because of lack or
829 overuse of resources.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:enumeration</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:restriction</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:simpleType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"JobSummary"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The complete representation of the state
830 of a job</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobId"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:JobIdentifier"</span><span class="markup">/&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"runId"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> this is a client supplied identifier -
831 the UWS system does nothing other than to return it as
832 part of the description of the job</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ownerId"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">the owner (creator) of the job -
833 this should be expressed as a string that can be
834 parsed in accordance with IVOA security standards. If
835 there was no authenticated job creator then this
836 should be set to NULL.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"phase"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ExecutionPhase"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the execution phase - returned at
837 /(jobs)/(jobid)/phase</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"quote"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> A Quote predicts when the job is likely to complete - returned at /(jobs)/(jobid)/quote
838 "don't know" is encoded by setting to the XML null value xsi:nil="true"</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"startTime"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The instant at which the job started execution.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"endTime"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The instant at which the job finished execution</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"executionDuration"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:int"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"false"</span><span class="markup">&gt;</span><div class="comment">&lt;!-- TODO look if xs:duration here has any benefits --&gt;</div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The duration (in seconds) for which
839 the job should be allowed to run - a value of 0 is
840 intended to mean unlimited - returned at
841 /(jobs)/(jobid)/executionduration</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"destruction"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:dateTime"</span> <span class="attribute-name">nillable</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The time at which the whole job +
842 records + results will be destroyed. returned at
843 /(jobs)/(jobid)/destruction</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:parameters"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The parameters to the job (where appropriate)
844 can also be retrieved at /(jobs)/(jobid)/parameters</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:results"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">The results for the job - can also be retrieved at /(jobs)/(jobid)/results</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"errorSummary"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ErrorSummary"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><span class="text">
845 </span><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobInfo"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"1"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> This is arbitrary information that can
846 be added to the job description by the UWS
847 implementation.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:any</span> <span class="attribute-name">namespace</span><span class="markup">=</span><span class="attribute-value">"##any"</span> <span class="attribute-name">processContents</span><span class="markup">=</span><span class="attribute-value">"lax"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:simpleType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"JobIdentifier"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The identifier for the job
848 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:restriction</span> <span class="attribute-name">base</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:simpleType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"job"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:JobSummary"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> This is the information that is returned
849 when a GET is made for a single job resource - i.e.
850 /(jobs)/(jobid)</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobs"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The list of job references returned at
851 /(jobs)</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> ISSUE - do we want to have any sort of
852 paging or selection mechanism in case the job list gets
853 very large? Or is that an unnecessary complication...
854 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"jobref"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ShortJobDescription"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ResultReference"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> A reference to a UWS result
855 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"id"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attributeGroup</span> <span class="attribute-name">ref</span><span class="markup">=</span><span class="attribute-value">"uws:reference"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"results"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> The element returned for
856 /(jobs)/(jobid)/results</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"result"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ResultReference"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ErrorSummary"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">
857 A short summary of an error - a fuller representation of the
858 error may be retrieved from /(jobs)/(jobid)/error
859 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"message"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"type"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:ErrorType"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">
860 characterization of the type of the error
861 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"hasDetail"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:boolean"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text">if true then there is a more detailed error message available at /(jobs)/(jobid)/error</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:simpleType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"ErrorType"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:restriction</span> <span class="attribute-name">base</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"transient"</span><span class="markup">/&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:enumeration</span> <span class="attribute-name">value</span><span class="markup">=</span><span class="attribute-value">"fatal"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:restriction</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:simpleType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"Parameter"</span> <span class="attribute-name">mixed</span><span class="markup">=</span><span class="attribute-value">"true"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the list of input parameters to the job - if
862 the job description language does not naturally have
863 parameters, then this list should contain one element which
864 is the content of the original POST that created the job.
865 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"byReference"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:boolean"</span> <span class="attribute-name">default</span><span class="markup">=</span><span class="attribute-value">"false"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> if this attribute is true then the
866 content of the parameter represents a URL to retrieve the
867 actual parameter value.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> It is up to the implementation to decide
868 if a parameter value cannot be returned directly as the
869 content - the basic rule is that the representation of
870 the parameter must allow the whole job element to be
871 valid XML. If this cannot be achieved then the parameter
872 value must be returned by reference.</span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"id"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:string"</span> <span class="attribute-name">use</span><span class="markup">=</span><span class="attribute-value">"required"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:annotation</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:documentation</span><span class="markup">&gt;</span><span class="text"> the identifier for the parameter
873 </span><span class="markup">&lt;/</span><span class="end-tag">xs:documentation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:annotation</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:attribute</span><span class="markup">&gt;</span></div><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:attribute</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"isPost"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"xs:boolean"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"parameters"</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:complexType</span><span class="markup">&gt;</span><div class="element"><span class="markup">&lt;</span><span class="start-tag">xs:sequence</span><span class="markup">&gt;</span><div class="indent"><span class="markup">&lt;</span><span class="start-tag">xs:element</span> <span class="attribute-name">name</span><span class="markup">=</span><span class="attribute-value">"parameter"</span> <span class="attribute-name">type</span><span class="markup">=</span><span class="attribute-value">"uws:Parameter"</span> <span class="attribute-name">maxOccurs</span><span class="markup">=</span><span class="attribute-value">"unbounded"</span> <span class="attribute-name">minOccurs</span><span class="markup">=</span><span class="attribute-value">"0"</span><span class="markup">/&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:sequence</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:complexType</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:element</span><span class="markup">&gt;</span></div><span class="markup">&lt;/</span><span class="end-tag">xs:schema</span><span class="markup">&gt;</span></div><div class="comment">&lt;!-- --&gt;</div></div></div>
874 </div>
875 </div>
876 <div class="section-nonum'"><h2><a name="References" id="References" shape="rect"/>References</h2>
877 <div>
878 <?bibliography ivoadoc/refs.bib ?>
879
880
881 <dl><dt><a name="std:rfc2119" id="std:rfc2119" shape="rect">[std:rfc2119] Bradner, S. </a></dt><dd>
882 <a href="http://www.ietf.org/rfc/rfc2119.txt" shape="rect">Key words for use in RFCs to Indicate Requirement Levels</a>, IETF RFC 2119, 1997</dd><dt><a name="std:xform" id="std:xform" shape="rect">[std:xform] John M. Boyer, editor.</a></dt><dd>
883 <a href="http://www.w3.org/TR/xforms11/" shape="rect">Xforms 1.1</a>, 2007.
884 </dd><dt><a name="std:http" id="std:http" shape="rect">[std:http] R. Fielding, J. Gettys, J. Mogul, H. Frystyk,
885 L. Masinter, P. Leach, and T. Berners-Lee.</a></dt><dd>
886 <a href="http://www.w3.org/Protocols/rfc2616/rfc2616.html" shape="rect">Hypertext
887 transfer protocol -- http/1.1</a>.
888 {rfc2616}, June 1999.
889 </dd><dt><a name="std:vospace" id="std:vospace" shape="rect">[std:vospace] Matthew Graham, Dave Morris, and Guy
890 Rixon, Matthew Graham, editor.</a></dt><dd>
891 <a href="http://www.ivoa.net/Documents/VOSpace/" shape="rect">Vospace specification</a>.
892 {IVOA Recommendation}, 2009.
893 </dd><dt><a name="std:soap" id="std:soap" shape="rect">[std:soap] Don Box, David Ehnebuske, Gopal Kakivaya,
894 Andrew Layman, Noah Mendelsohn, Henrik Frystyk Nielsen, Satish Thatte, and
895 Dave Winer.</a></dt><dd>
896 <a href="http://www.w3.org/TR/2000/NOTE-SOAP-20000508/" shape="rect">Simple object access
897 protocol (soap) 1.1</a>, 2000.
898 </dd><dt><a name="fielding00" id="fielding00" shape="rect">[fielding00] Roy Thomas Fielding.</a></dt><dd>
899 <a href="http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm" shape="rect"><em>Architectural Styles and the Design of Network-based Software
900 Architectures</em></a>.
901 PhD thesis, University of California, Irvine, 2000.
902 </dd><dt><a name="std:iso8601" id="std:iso8601" shape="rect">[std:iso8601] ISO 8601:2004 Data elements and interchange formats - Information interchange - Representation of dates and times</a></dt><dd>
903 International Organization for
904 Standardization, 2004.
905 </dd><dt><a name="std:ssoauth" id="std:ssoauth" shape="rect">[std:ssoauth] {Grid and Web Services Working Group},
906 Guy Rixon and Matthew Graham, editors.</a></dt><dd>
907 <a href="http://www.ivoa.net/Documents/latest/SSOAuthMech.html" shape="rect">Ivoa
908 single-sign-on profile: Authentication mechanisms version 1.01</a>, 2008.
909 </dd><dt><a name="harrison05" id="harrison05" shape="rect">[harrison05] P. Harrison.</a></dt><dd>
910 <a href="http://www.ivoa.net/Documents/latest/CEA.html" shape="rect">A proposal for a
911 common execution architecture</a>.
912 {IVOA Note}, May 2005.
913 </dd><dt><a name="std:vocea" id="std:vocea" shape="rect">[std:vocea] Paul Harrison.</a></dt><dd>
914 VOCEA - an xml schema for registering cea.</dd><dt><a name="sextractor" id="sextractor" shape="rect">[sextractor]
915 http://astromatic.iap.fr/software/sextractor/.</a></dt><dd>
916 <a href="http://astromatic.iap.fr/software/sextractor/" shape="rect">Sextractor</a>.
917 [Online].
918 </dd><dt><a name="std:adql" id="std:adql" shape="rect">[std:adql] Iñaki Ortiz, Jeff Lusted, Pat Dowler,
919 Alexander Szalay, Yuji Shirasaki, Maria A. Nieto-Santisteba, Masatoshi
920 Ohishi, William O'Mullane, Pedro Osuna, the VOQL-TEG, and the VOQL
921 Working Group, Pedro Osuna and Iñaki Ortiz, editors.</a></dt><dd>
922 <a href="http://www.ivoa.net/Documents/latest/ConeSearch.html" shape="rect">Ivoa
923 astronomical data query language</a>.
924 {IVOA Recommendation}, 2008.
925 </dd><dt><a name="std:siap" id="std:siap" shape="rect">[std:siap] Doug Tody and Ray Plant, Paul Harrison,
926 editor.</a></dt><dd>
927 <a href="http://www.ivoa.net/Documents/latest/SIA.html" shape="rect">Simple image access
928 specification</a>.
929 {IVOA Recommendation}, 2009.
930 </dd><dt><a name="std:scs" id="std:scs" shape="rect">[std:scs] Roy Williams, Robert Hanisch, Alex Szalay, and
931 Raymond Plante, Raymond Plante, editor.</a></dt><dd>
932 <a href="http://www.ivoa.net/Documents/latest/ConeSearch.html" shape="rect">Simple cone
933 search</a>.
934 {IVOA Recommendation}, 2008.
935 </dd></dl>
936 </div>
937 </div>
938 </div><p style="text-align: right; font-size: x-small; color: #888;">
939 $Revision$ $Date$ $HeadURL$</p></body></html>

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