/* ==========================================
* JGraphT : a free Java graph-theory library
* ==========================================
*
* Project Info: http://jgrapht.sourceforge.net/
* Project Creator: Barak Naveh (http://sourceforge.net/users/barak_naveh)
*
* (C) Copyright 2003-2008, by Barak Naveh and Contributors.
*
* This program and the accompanying materials are dual-licensed under
* either
*
* (a) the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation, or (at your option) any
* later version.
*
* or (per the licensee's choosing)
*
* (b) the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation.
*/
/* ------------------
* GraphMLExporter.java
* ------------------
* (C) Copyright 2006, by Trevor Harmon.
*
* Original Author: Trevor Harmon <trevor@vocaro.com>
*
*/
package org.jgrapht.ext;
import java.io.*;
import javax.xml.transform.*;
import javax.xml.transform.sax.*;
import javax.xml.transform.stream.*;
import org.jgrapht.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
/**
* Exports a graph into a GraphML file.
*
* <p>For a description of the format see <a
* href="http://en.wikipedia.org/wiki/GraphML">
* http://en.wikipedia.org/wiki/GraphML</a>.</p>
*
* @author Trevor Harmon
*/
public class GraphMLExporter<V, E>
{
private VertexNameProvider<V> vertexIDProvider;
private VertexNameProvider<V> vertexLabelProvider;
private EdgeNameProvider<E> edgeIDProvider;
private EdgeNameProvider<E> edgeLabelProvider;
/**
* Constructs a new GraphMLExporter object with integer name providers for
* the vertex and edge IDs and null providers for the vertex and edge
* labels.
*/
public GraphMLExporter()
{
this(
new IntegerNameProvider<V>(),
null,
new IntegerEdgeNameProvider<E>(),
null);
}
/**
* Constructs a new GraphMLExporter object with the given ID and label
* providers.
*
* @param vertexIDProvider for generating vertex IDs. Must not be null.
* @param vertexLabelProvider for generating vertex labels. If null, vertex
* labels will not be written to the file.
* @param edgeIDProvider for generating vertex IDs. Must not be null.
* @param edgeLabelProvider for generating edge labels. If null, edge labels
* will not be written to the file.
*/
public GraphMLExporter(
VertexNameProvider<V> vertexIDProvider,
VertexNameProvider<V> vertexLabelProvider,
EdgeNameProvider<E> edgeIDProvider,
EdgeNameProvider<E> edgeLabelProvider)
{
this.vertexIDProvider = vertexIDProvider;
this.vertexLabelProvider = vertexLabelProvider;
this.edgeIDProvider = edgeIDProvider;
this.edgeLabelProvider = edgeLabelProvider;
}
/**
* Exports a graph into a plain text file in GraphML format.
*
* @param writer the writer to which the graph to be exported
* @param g the graph to be exported
*/
public void export(Writer writer, Graph<V, E> g)
throws SAXException, TransformerConfigurationException
{
// Prepare an XML file to receive the GraphML data
PrintWriter out = new PrintWriter(writer);
StreamResult streamResult = new StreamResult(out);
SAXTransformerFactory factory =
(SAXTransformerFactory) SAXTransformerFactory.newInstance();
TransformerHandler handler = factory.newTransformerHandler();
Transformer serializer = handler.getTransformer();
serializer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
serializer.setOutputProperty(OutputKeys.INDENT, "yes");
handler.setResult(streamResult);
handler.startDocument();
AttributesImpl attr = new AttributesImpl();
// <graphml>
handler.startPrefixMapping(
"xsi",
"http://www.w3.org/2001/XMLSchema-instance");
// FIXME: Is this the proper way to add this attribute?
attr.addAttribute(
"",
"",
"xsi:schemaLocation",
"CDATA",
"http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd");
handler.startElement(
"http://graphml.graphdrawing.org/xmlns",
"",
"graphml",
attr);
handler.endPrefixMapping("xsi");
if (vertexLabelProvider != null) {
// <key> for vertex label attribute
attr.clear();
attr.addAttribute("", "", "id", "CDATA", "vertex_label");
attr.addAttribute("", "", "for", "CDATA", "node");
attr.addAttribute("", "", "attr.name", "CDATA", "Vertex Label");
attr.addAttribute("", "", "attr.type", "CDATA", "string");
handler.startElement("", "", "key", attr);
handler.endElement("", "", "key");
}
if (edgeLabelProvider != null) {
// <key> for edge label attribute
attr.clear();
attr.addAttribute("", "", "id", "CDATA", "edge_label");
attr.addAttribute("", "", "for", "CDATA", "edge");
attr.addAttribute("", "", "attr.name", "CDATA", "Edge Label");
attr.addAttribute("", "", "attr.type", "CDATA", "string");
handler.startElement("", "", "key", attr);
handler.endElement("", "", "key");
}
// <graph>
attr.clear();
attr.addAttribute(
"",
"",
"edgedefault",
"CDATA",
(g instanceof DirectedGraph<?, ?>) ? "directed" : "undirected");
handler.startElement("", "", "graph", attr);
// Add all the vertices as <node> elements...
for (V v : g.vertexSet()) {
// <node>
attr.clear();
attr.addAttribute(
"",
"",
"id",
"CDATA",
vertexIDProvider.getVertexName(v));
handler.startElement("", "", "node", attr);
if (vertexLabelProvider != null) {
// <data>
attr.clear();
attr.addAttribute("", "", "key", "CDATA", "vertex_label");
handler.startElement("", "", "data", attr);
// Content for <data>
String vertexLabel = vertexLabelProvider.getVertexName(v);
handler.characters(
vertexLabel.toCharArray(),
0,
vertexLabel.length());
handler.endElement("", "", "data");
}
handler.endElement("", "", "node");
}
// Add all the edges as <edge> elements...
for (E e : g.edgeSet()) {
// <edge>
attr.clear();
attr.addAttribute(
"",
"",
"id",
"CDATA",
edgeIDProvider.getEdgeName(e));
attr.addAttribute(
"",
"",
"source",
"CDATA",
vertexIDProvider.getVertexName(g.getEdgeSource(e)));
attr.addAttribute(
"",
"",
"target",
"CDATA",
vertexIDProvider.getVertexName(g.getEdgeTarget(e)));
handler.startElement("", "", "edge", attr);
if (edgeLabelProvider != null) {
// <data>
attr.clear();
attr.addAttribute("", "", "key", "CDATA", "edge_label");
handler.startElement("", "", "data", attr);
// Content for <data>
String edgeLabel = edgeLabelProvider.getEdgeName(e);
handler.characters(
edgeLabel.toCharArray(),
0,
edgeLabel.length());
handler.endElement("", "", "data");
}
handler.endElement("", "", "edge");
}
handler.endElement("", "", "graph");
handler.endElement("", "", "graphml");
handler.endDocument();
out.flush();
}
}
// End GraphMLExporter.java