java - Using the library JUNG graphs -

i use jung java library manage graphs , want know how color connected nodes same color distinguish connected components.

for example, want nodes 2, 3 , 4 have same color , node 1to have color, knowing adjacency matrix is:

0 0 0 0 0 0 1 1 0 1 0 1 0 1 1 0 

code create graph (nodes have same color):

 graph<integer, string> g; /** creates new instance of simplegraphview */ public readfile(int nbsommet,int [] [] nodemat) {     // graph<v, e> v type of vertices , e type of edges     // note showing use of sparsegraph rather sparsemultigraph     g = new sparsegraph<integer, string>();     // add vertices. above defined these type integer.     /*for (int = 1; <=nbsommet; i++) {         g.addvertex((integer)i);      }*/        (int = 1; <=nbsommet; i++)        {  g.addvertex((integer)i);            (int j = 1; j<=nbsommet; j++)             {                if((nodemat[i][j]==1)&& (j>i))                {   if(!(g.getvertices().contains(j)))                { g.addvertex((integer)j);}                    g.addedge(i+" "+j, i, j);                    }      }}} //...   readfile sgv = new readfile(nbsommet,nodematfinal); // builds graph   //design sgv1 = new design();      layout<integer, string> layout = new kklayout (sgv.g);     //treelayout  layout = new treelayout(sgv.g,100,100);     layout.setsize(new dimension(800,800));       basicvisualizationserver<integer, string> vv = new   basicvisualizationserver<integer, string>(layout);      transformer<integer,paint> vertexpaint = new transformer<integer,paint>() {         public paint transform(integer i) {             return (paint) color.green;         }     };        vv.setpreferredsize(new dimension(850,850));     vv.getrendercontext().setvertexlabelrenderer(new        defaultvertexlabelrenderer(color.green));     vv.getrendercontext().setedgedrawpainttransformer(new constanttransformer(color.white));     vv.getrendercontext().setedgestroketransformer(new constanttransformer(new basicstroke(2.5f)));      vv.getrendercontext().setvertexfillpainttransformer((transformer<integer, java.awt.paint>) vertexpaint);     vv.getrendercontext().setvertexfillpainttransformer(new pickablevertexpainttransformer<integer>(vv.getpickedvertexstate(), color.green, color.yellow));      vv.setbackground(color.gray);     vv.getrendercontext().setvertexlabeltransformer(new tostringlabeller<integer>());     vv.getrenderer().getvertexlabelrenderer().setposition(position.cntr);       jframe frame = new jframe("graph");     frame.setdefaultcloseoperation(jframe.exit_on_close);     frame.getcontentpane().add(vv);      frame.pack();     frame.setvisible(true);  

so how change code have connected components different colors

the jung library not let set different renderers per vertex, instead use 1 renderer , put of logic there. (i got idea this post).

you have determine vertices should colors, , put either in method call or map<integer, color>. assume latter:

final map<integer,color> colormapping = new hashmap<integer, color>();  // .....  transformer<integer,paint> vertexpaint = new transformer<integer,paint>()  {     public paint transform(integer i)     {         return colormapping.get(i.intvalue());     } }; 

obviously leaves question how fill colormapping.
need determine connected components adjacency matrix; separate problem has been handled in this stackoverflow post.
once have separate subgraphs, left assign colors them, , fill colormapping accordingly.

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a few notes on code sample:

1. i had comment call out:

   vv.getrendercontext().setvertexfillpainttransformer(new pickablevertexpainttransformer<integer>(vv.getpickedvertexstate(), color.green, color.yellow));

   it sets new painttransformer replaces 1 calls vertexpaint.

2. your graph initialization 1-based, array 0-based. should change

   if((nodemat[i][j]==1)&& (j>i))

   into

   if((nodemat[i-1][j-1]==1)&& (j>i))

   or arrayindexoutofboundsexception.