CODEWITHSUNDEEP
javagraphiterationjgrapht
Nick Heiner
Nick Heiner

Reputation: 122450

Java: JGraphT: Iterate through nodes

I'm trying to iterate through all nodes, so I can print them out for graphviz. What is the best way to do that using the JGraphT library?

public static void main(String[] args) {
    UndirectedGraph<String, DefaultEdge> g = new SimpleWeightedGraph<String, DefaultEdge>(DefaultEdge.class);

    String odp = "ODP";
    String cck = "CCK";
    String mfe = "MFE";

    g.addVertex(odp);
    g.addVertex(cck);
    g.addVertex(mfe);

    g.addEdge(odp, cck);
    g.addEdge(odp, mfe);

}

Also, how do I add edge weights?

Edit: This seems to work pretty well. But is there a better way?

    Set<DefaultEdge> edges = g.edgeSet();

    for (DefaultEdge e : edges) {
        gv.addln(String.format("\"%s\" -> \"%s\"", g.getEdgeSource(e), g.getEdgeTarget(e)));            
    }

Upvotes: 2

Views: 5900

Answers (3)

Manuel Cantonero
Manuel Cantonero

Reputation: 135

you can print all the information of the graph using the function toString() over your graph, for example if you have a graph h, you can do it:

System.out.println(h.toString());

On this way you will see the graph in a line. On the other hand, you can visualize the graph allocating coordinates to the vertexs, for example with your graph:

positionVertexAt(ODP, 130, 40);
positionVertexAt(CCK, 60, 20);
positionVertexAt(MFE, 240, 140);

Problem, that you have to implement some function, you have a example in this link http://kickjava.com/src/org/jgrapht/demo/JGraphAdapterDemo.java.htm.

I think is a little difficult, but you can create the nice graph visualization.

In addition you can use the web http://www.graphviz.org where you can format the information of your graph like you did already and then the program build the graph, like in this example if you type this code (is the code of the example of the web):

digraph finite_state_machine {
rankdir=LR;
size="8,5"
node [shape = doublecircle]; LR_0 LR_3 LR_4 LR_8;
node [shape = circle];
LR_0 -> LR_2 [ label = "SS(B)" ];
LR_0 -> LR_1 [ label = "SS(S)" ];
LR_1 -> LR_3 [ label = "S($end)" ];
LR_2 -> LR_6 [ label = "SS(b)" ];
LR_2 -> LR_5 [ label = "SS(a)" ];
LR_2 -> LR_4 [ label = "S(A)" ];
LR_5 -> LR_7 [ label = "S(b)" ];
LR_5 -> LR_5 [ label = "S(a)" ];
LR_6 -> LR_6 [ label = "S(b)" ];
LR_6 -> LR_5 [ label = "S(a)" ];
LR_7 -> LR_8 [ label = "S(b)" ];
LR_7 -> LR_5 [ label = "S(a)" ];
LR_8 -> LR_6 [ label = "S(b)" ];
LR_8 -> LR_5 [ label = "S(a)" ];

}

the program will build this graph : http://www.graphviz.org/content/fsm

I write to you the web here : http://www.graphviz.org/. I hope I could help you, if I find more information or something easier I will tell you.

Pd: Sorry for my English I hope you can understand all.

Upvotes: 1

Omair
Omair

Reputation: 874

Instead of using DefaultEdge in the code given by Aaron, you should actually use DefaultWeightedEdge

Upvotes: 0

Aaron
Aaron

Reputation: 1605

Try using WeightedGraph instead of UndirectedGraph (in answer to your second question about adding weights):

WeightedGraph<String, DefaultEdge> g = new SimpleWeightedGraph<String, DefaultEdge>(DefaultEdge.class);

String odp = "ODP";
String cck = "CCK";
String mfe = "MFE";

g.addVertex(odp);
g.addVertex(cck);
g.addVertex(mfe);

DefaultEdge e1 = g.addEdge(odp, cck);
DefaultEdge e1 = g.addEdge(odp, mfe);

g.setEdgeWeight(e1, 10);
g.setEdgeWeight(e2, 4);

Upvotes: 0

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