graphtoxgmmlsaxhandler.java

OpenJGraph是一个开源的Java库

package salvo.jesus.graph.xml;

import salvo.jesus.graph.*;
import salvo.jesus.graph.visual.*;
import java.io.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
import org.apache.xml.serialize.*;
import org.apache.xerces.parsers.*;
import org.apache.xerces.utils.*;
import org.apache.xerces.framework.*;
import java.util.*;

/**
 * An implmentation of GraphToXMLHandler that serializes a Graph and/or
 * VisualGraph to XGMML via SAX.
 * <p>
 * This class simply delegates handling of events to either the inner class
 * <tt>GraphToXGMMLSAXHandler.GraphHandler</tt> or
 * <tt>GraphToXGMMLSAXHandler.VisualGraphHandler</tt>, depending on which
 * method between <tt>startSerialize()</tt> is called. Users should simply create
 * an instance of this class and should not be concerned of the inner classes,
 * and call the appropriate overloaded <tt>startSerialize()</tt> method.
 * <p>
 *
 * See <a href="http://www.cs.rpi.edu/~puninj/XGMML/draft-xgmml-20001006.html">
 * XGMML 1.0 Draft Specification</a>
 *
 * @author  Jesus M. Salvo Jr.
 */

public class GraphToXGMMLSAXHandler implements GraphToXMLHandler {

    private GraphToXMLEventGenerator    eventGenerator;
    protected XMLSerializer             serializer;

    /**
     * Delegate that performs the actual serialization
     */
    private GraphToXGMMLSAXHandler      delegate;

    public GraphToXGMMLSAXHandler( GraphToXMLEventGenerator eventGenerator, XMLSerializer serializer ) {
        this.eventGenerator = eventGenerator;
        this.serializer = serializer;
    }

    /**
     * Initializes the delegate to be the inner class <tt>GraphHandler</tt>,
     * and calls the <tt>startSerialize()</tt> method of the delegate.
     */
    public void startSerialize( Graph graph ) throws Exception
    {
        this.delegate = new GraphHandler( this.eventGenerator, this.serializer,
            new CommonHandler( this.eventGenerator, this.serializer ) );
        this.delegate.startSerialize( graph );
    }

    /**
     * Initializes the delegate to be the inner class <tt>VisualGraphHandler</tt>,
     * and calls the <tt>startSerialize()</tt> method of the delegate.
     */
    public void startSerialize( VisualGraph vGraph ) throws Exception {
        this.delegate = new VisualGraphHandler( this.eventGenerator, this.serializer,
            new CommonHandler( this.eventGenerator, this.serializer ) );
        this.delegate.startSerialize( vGraph );
    }

    /**
     * Calls the delegate's <tt>serializerEdge()</tt> method
     */
    public void serializeEdge( Edge edge ) throws Exception
    {
        this.delegate.serializeEdge( edge );
    }

    /**
     * Calls the delegate's <tt>endSerializerEdge()</tt> method
     */
    public void endSerializeEdge( Edge edge ) throws Exception {
        this.delegate.endSerializeEdge( edge );
    }

    /**
     * Calls the delegate's <tt>serializerVertex()</tt> method
     */
    public void serializeVertex( Vertex vertex ) throws Exception
    {
        this.delegate.serializeVertex( vertex );
    }

    /**
     * Calls the delegate's <tt>endSerializerVertex()</tt> method
     */
    public void endSerializeVertex( Vertex vertex ) throws Exception {
        this.delegate.endSerializeVertex( vertex );
    }

    /**
     * Calls the delegate's <tt>serializerVertex()</tt> method
     */
    public void endSerialize() throws Exception {
        this.delegate.endSerialize();
    }

    public GraphToXMLEventGenerator getEventGenerator() {
        return this.eventGenerator;
    }

    /**
     * Methods and instance variables common to either of the two inner class delegates
     * <tt>GraphHandler</tt> and <tt>VisualGraphHandler</tt>.
     *
     * @author  Jesus M. Salvo Jr.
     */
    class CommonHandler extends GraphToXGMMLSAXHandler {

        /**
         * Index of the DTD's name in the pool of Strings
         */
        protected int    DOCTYPE_NAME_STRINGPOOL_INDEX;

        /**
         * Index of the Public ID in the pool of Strings
         */
        protected int    PUBLIC_ID_STRINGPOOL_INDEX;

        /**
         * Index of the System ID in the pool of Strings
         */
        protected int    SYSTEM_ID_STRINGPOOL_INDEX;

        /**
         * Index of the "OpenJGraph" literal in the pool of Strings
         */
        protected int    OPENJGRAPH_LITERAL_STRINGPOOL_INDEX;

        /**
         * Index of the "graph" literal in the pool of Strings
         */
        protected int    GRAPH_ELEMENT_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "Vendor" literal in the pool of Strings
         */
        protected int    VENDOR_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "directed" literal in the pool of Strings
         */
        protected int    DIRECTED_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "Graphic" literal in the pool of Strings
         */
        protected int    GRAPHIC_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;

        /**
         * Index of the "att" literal in the pool of Strings
         */
        protected int    ATT_ELEMENT_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "weighted" literal in the pool of Strings
         */
        protected int    ATT_ELEMENT_NAME_ATTRIBUTE_VALUE_WEIGHTED_STRINGPOOL_INDEX;
        /**
         * Index of the "dag" literal in the pool of Strings
         */
        protected int    ATT_ELEMENT_NAME_ATTRIBUTE_VALUE_DAG_STRINGPOOL_INDEX;
        /**
         * Index of the "type" literal in the pool of Strings
         */
        protected int    TYPE_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "name" literal in the pool of Strings
         */
        protected int    NAME_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "value" literal in the pool of Strings
         */
        protected int    VALUE_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;

        /**
         * Index of the "node" literal in the pool of Strings
         */
        protected int    NODE_ELEMENT_LITERAL_STRINGPOOL_INDEX;

        /**
         * Index of the "edge" literal in the pool of Strings
         */
        protected int    EDGE_ELEMENT_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "source" literal in the pool of Strings
         */
        protected int    SOURCE_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "target" literal in the pool of Strings
         */
        protected int    TARGET_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "weight" literal in the pool of Strings
         */
        protected int    WEIGHT_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;

        /**
         * Index of the "id" literal in the pool of Strings
         */
        protected int    ID_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "label" literal in the pool of Strings
         */
        protected int    LABEL_ATTRIBUTE_LITERAL_STRINGPOOL_INDEX;

        /**
         * Index of the "string" literal in the pool of Strings
         */
        protected int    STRING_TYPE_STRINGPOOL_INDEX;
        /**
         * Index of the "integer" literal in the pool of Strings
         */
        protected int    INTEGER_TYPE_STRINGPOOL_INDEX;
        /**
         * Index of the "double" literal in the pool of Strings
         */
        protected int    DOUBLE_TYPE_STRINGPOOL_INDEX;
        /**
         * Index of the "boolean" literal in the pool of Strings
         */
        protected int    BOOLEAN_TYPE_STRINGPOOL_INDEX;

        /**
         * Index of the "1" literal in the pool of Strings
         */
        protected int    ZERO_LITERAL_STRINGPOOL_INDEX;
        /**
         * Index of the "0" literal in the pool of Strings
         */
        protected int    ONE_LITERAL_STRINGPOOL_INDEX;

        private XMLReaderAdapter    readerAdapter;
        private Graph       graph;
        private SAXParser   parser;
        // Wrap the parser with a XMLReaderAdapter so that we can call
        // startElement() and endElement() methods.
        private OutputFormat        format;
        private TreeMap     vertexIDMap;
        private long        idAttribute;

        /**
         * A pool of Strings that we will use often throughout the serialization.
         * These Strings include the element's name, attributes names, and possibly
         * values as well.
         */
        private StringPool  sPool;


        public CommonHandler( GraphToXMLEventGenerator eventGenerator, XMLSerializer serializer ) {
            super( eventGenerator, serializer );
            this.sPool = this.initStringPool();
        }

        /**
         * Initialized the SAXParser, XMLReaderAdapter and OutputFormat.
         * Serializes the DTD declaration.
         */
        public void startSerialize( Graph graph ) throws Exception {
            this.graph = graph;
            // Create a SAX2 parser: org.apache.xerces.parsers.SAXParser
            this.parser = new SAXParser();
            // Wrap the parser with a XMLReaderAdapter so that we can call
            // startElement() and endElement() methods.
            this.readerAdapter = new XMLReaderAdapter( parser );
            this.format = new OutputFormat();
            // Reference to the mappings between a vertex and its ID attribute
            this.vertexIDMap = new TreeMap( new VertexComparator() );
            // The id attribute that we assign to all elements
            this.idAttribute = 1;

            // Initialise the OutputFormat
            this.format.setOmitXMLDeclaration( false );
            this.format.setEncoding( OutputFormat.Defaults.Encoding );
            this.format.setIndenting( true );
            this.format.setDoctype( XGMML.PUBLIC_ID, XGMML.SYSTEM_ID );

            // Tell the serializer the OutputFormat to use
            this.serializer.setOutputFormat( format );

            // Tell the parser the ContentHander to use
            this.parser.setContentHandler( this.serializer );

            this.parser.startDocument();

            // Serialize the DTD declaration
            this.parser.startDTD( new QName( -1,
                    this.DOCTYPE_NAME_STRINGPOOL_INDEX, this.DOCTYPE_NAME_STRINGPOOL_INDEX ),
                this.PUBLIC_ID_STRINGPOOL_INDEX,
                this.SYSTEM_ID_STRINGPOOL_INDEX );
            this.parser.endDTD();

            // Tell the XMLReaderAdapter the DocumentHandler to use
            // Even though we have told the parser the ContentHandler to use,
            // remember that the XMLReadeAdapter is a wrapper around the SAXParser.
            // Therefore we need to indepedently tell the this adapter to DocumentHandler
            this.readerAdapter.setDocumentHandler( this.serializer );
        }

        /**
         * Empty method implementation
         */
        public void startSerialize( VisualGraph vGraph ) throws Exception {}

        /**
         * Empty method implementation
         */
        public void serializeVertex( Vertex vertex ) throws Exception {}

        /**
         * Serializes the end of the Vertex's element and maps
         * the Vertex to the unique ID attribute.
         */
        public void endSerializeVertex( Vertex vertex ) throws Exception {
            this.readerAdapter.endElement( "",
                XGMML.NODE_ELEMENT_LITERAL, XGMML.NODE_ELEMENT_LITERAL );

            // Store the mapping between the vertex and the ID attribute
            // This is later used when writing out the edges
            this.vertexIDMap.put( vertex, new Long( idAttribute ));
            this.incremenetIDAttribute();
        }

        /**
         * Empty method implementation
         */
        public void serializeEdge( Edge edge ) throws Exception {}

        /**