GexfWriter.java

package org.jboss.windup.reporting.renderer.gexf;

import java.io.IOException;
import java.io.OutputStream;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.jboss.windup.reporting.renderer.GraphDataSerializer;

import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Edge;
import com.tinkerpop.blueprints.Graph;
import com.tinkerpop.blueprints.Vertex;

public class GexfWriter implements GraphDataSerializer
{

    protected final Graph graph;
    protected String defaultEdgeType = "directed";
    protected String mode = "static";
    protected String vertexLabelProperty = "label";
    protected String edgeLabel = null;

    public GexfWriter(Graph graph)
    {
        this.graph = graph;
    }

    public GexfWriter(Graph graph, String mode, String defaultEdgeType, String vertexLabelProperty, String edgeLabel)
    {
        this.graph = graph;
        this.mode = mode;
        this.defaultEdgeType = defaultEdgeType;
        this.vertexLabelProperty = vertexLabelProperty;
        this.edgeLabel = edgeLabel;
    }

    public void writeGraph(OutputStream os) throws IOException
    {
        writeGexf(os);
    }

    private void writeGexf(OutputStream os) throws IOException
    {
        IOUtils.write(GexfConstants.OPENING_TAG, os);
        writeGraphTag(mode, defaultEdgeType, os);
        IOUtils.write(GexfConstants.CLOSING_TAG, os);
    }

    private void writeGraphTag(String mode, String edgeType, OutputStream os) throws IOException
    {
        final String tag = StringUtils.replaceEach(GexfConstants.GRAPH_NODE_OPEN, new String[] { "%1", "%2" },
                    new String[] { mode, edgeType });
        IOUtils.write(tag, os);

        writeGraphNodes(os);
        writeGraphEdges(os);

        IOUtils.write(GexfConstants.GRAPH_NODE_CLOSE, os);
    }

    private void writeGraphEdges(OutputStream os) throws IOException
    {
        IOUtils.write(GexfConstants.EDGES_OPEN, os);

        for (Edge edge : graph.getEdges())
        {
            String id = "" + edge.getId().hashCode();
            String source = "" + edge.getVertex(Direction.OUT).getId().toString();
            String target = "" + edge.getVertex(Direction.IN).getId().toString();
            writeGraphEdge(id, source, target, os);
        }

        IOUtils.write(GexfConstants.EDGES_CLOSE, os);
    }

    private void writeGraphEdge(String id, String source, String target, OutputStream os) throws IOException
    {
        final String tag = StringUtils.replaceEach(GexfConstants.EDGE_TAG, new String[] { "%1", "%2", "%3" },
                    new String[] { id, source, target });
        IOUtils.write(tag, os);
    }

    private void writeGraphNode(String id, String label, OutputStream os) throws IOException
    {
        final String tag = StringUtils.replaceEach(GexfConstants.NODE_TAG,
                    new String[] { "%1", "%2" },
                    new String[] { id, label });
        IOUtils.write(tag, os);
    }

    private void writeGraphNodes(OutputStream os) throws IOException
    {

        IOUtils.write(GexfConstants.NODES_OPEN, os);
        // iterate the nodes.
        for (Vertex vertex : graph.getVertices())
        {
            String id = "" + vertex.getId().toString();
            String label = vertex.getProperty(vertexLabelProperty);

            if (StringUtils.isBlank(label))
            {
                label = vertex.toString();
            }
            writeGraphNode(id, label, os);
        }
        IOUtils.write(GexfConstants.NODES_CLOSE, os);

    }

}