如何在JUNG图形可视化中添加自定义顶点标签？

Question

How to use custom vertex labels in JUNG graph visualization?

I am following Jung 2.0 Tutorial where I found that setVertexLabelTransformer() can be used to label the vertices, but these labels cannot be customized, to my knowledge.

For example, the below code produces three vertices, having vertex-labels 1,2,4:

import edu.uci.ics.jung.algorithms.layout.CircleLayout;
import edu.uci.ics.jung.algorithms.layout.Layout;
import edu.uci.ics.jung.graph.Graph;
import edu.uci.ics.jung.graph.SparseMultigraph;
import edu.uci.ics.jung.visualization.BasicVisualizationServer;
import java.awt.Dimension;
import javax.swing.JFrame;

public class SimpleGraphView {
    Graph<Integer, String> g;

    public SimpleGraphView() {       
        g = new SparseMultigraph<Integer, String>();
        g.addVertex((Integer)1);
        g.addVertex((Integer)2);
        g.addVertex((Integer)4); 
    }

    public static void main(String[] args) {
        SimpleGraphView sgv = new SimpleGraphView(); 
        Layout<Integer, String> layout = new CircleLayout(sgv.g);
        layout.setSize(new Dimension(800,800));  
        BasicVisualizationServer<Integer,String> vv =
            new BasicVisualizationServer<Integer,String>(layout);
        vv.setPreferredSize(new Dimension(850,850)); 

        JFrame frame = new JFrame("Simple Graph View");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(vv); 
        frame.pack();
        frame.setVisible(true);       
    }
}

How do I add labels like "q0"?

Answer 1

Since you have defined the generics of SparseMultigraph<V, E> as SparseMultigraph<Integer, String> where the generic V for vertex as Integer and the generic E for edge as String , hence each vertex's label value is in Integer and each edge's label in String . So, if you want each vertex by names like q1, v2, etc., use String for generic V , so you can pass a vertex name like this g.addVertex("q1");

Answer 2

If you have a custom class for nodes, I will give an example from my project. I have a class Node which is like :

public class Node 
{

public long tweetId = 0L;
public long nodeId = 0L;
public String screenName = "";
public Date reTweetDate = new Date();
public boolean isMainNode = false;
public int size = 0;

public Node()
{
}

}

// You just need to override transform like below:

vv.getRenderContext().setVertexLabelTransformer(new ToStringLabeller() {
                @Override
                public String transform(Object v) {

                    return ((Node)v).screenName;
                }});

// It will show the screenName property as a label for each node in the graph. // I hope this is what you are looking for.