\input pstricks
\input pst-node
\nopagenumbers
\font\rm cmss10
\font\it cmssi10
\font\bf cmssbx10
\parindent=0pt
\hsize=8cm
\vsize=4cm
\rm

\def\boxsz{2.5cm}
\psset{cornersize=absolute,nodesep=1pt}

\def\compobox#1#2{\rnode{#2}{\psframebox[linearc=5pt,fillstyle=solid,linecolor=#1]{%
	\hbox
	{\hskip 2pt\vbox{\vskip 2pt\hbox to\boxsz{\hss #2\hss}\vskip 2pt}\hskip 2pt}}}}
\def\nfil#1{\hskip 0pt plus #1 fil}
\def\hidewidth#1{\hbox to 0pt{\hss #1\hss}}
\def\\{\hfil\break}

\line{\gray\compobox{gray}{vr:Service}\hfil}
\vfil
\line{\compobox{black}{DataResource}\hfil\compobox{black}{DataService}}
\vfil
\line{\compobox{black}{CatalogResource}\hfil\compobox{black}{CatalogService}}

\ncline{->}{vr:Service}{DataResource}
\ncline{->}{DataResource}{CatalogResource}
\ncline{->}{DataResource}{DataService}
\ncline{->}{CatalogResource}{CatalogService}

\eject\end