Prefuse API java creating edges

Question

I am using prefuse lately to make some visualizations. What I do is I load some information from a database, make a prefuse table instance for them and make a graph based on that information. This works fine.

My question is how can I create the edges for that graph??

I assume I must create another table to hold the edges but i don't know the way to create that thing... Any help appreciated! Thank you!

That's my code for setting up the data for the graph:

    Table nodeData = null;
    String query1 = "my_select_statement";

    try {
        nodeData = datasrc.getData(query1);

    } catch (DataIOException ex) {
        ex.getMessage();
        ex.printStackTrace();
    }

Graph graph = new Graph(nodeData, true);

score 0 · Answer 1 · answered Sep 19 '12 at 00:50

There is a constructor for a prefuse Graph that takes an edge table, as you suggest:

public Graph(Table nodes, Table edges, boolean directed)

I suggest you check out this very simple space delimited matrix reader for reference: https://github.com/brycecr/msmexplorer/blob/master/MSMExplorer/src/edu/stanford/folding/msmexplorer/io/DatGraphReader.java

In short, you do just create a table, but you need "source" and "target" columns where the entries into those columns are 0-indexed indicies into the node table. Creating the columns:

m_edgeTable = new Table();
m_edgeTable.addColumn(Graph.DEFAULT_SOURCE_KEY, int.class); //0th
m_edgeTable.addColumn(Graph.DEFAULT_TARGET_KEY, int.class); //1st

assigning source & target columns:

m_edgeTable.addRow();
m_edgeTable.set(rowNum, 0, sourceNodeIndex);
m_edgeTable.set(rowNum, 1, targetNodeIndex);

You had the right idea!

P.S.: If you're writing a graph reader, as it appears you are, I really recommend subclassing AbstractGraphReader. It will make your life easier down the road, as you can use your new class in the same way as the built in graph readers.

Prefuse API java creating edges

1 Answers1