saxeventrecorder.java

解决如何把XML应用到JAVA里问题

/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package org.dom4j.io;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.dom4j.Namespace;
import org.dom4j.QName;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.DTDHandler;
import org.xml.sax.SAXException;
import org.xml.sax.ext.DeclHandler;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.helpers.DefaultHandler;

/**
 * <p>
 * Records SAX events such that they may be "replayed" at a later time. Provides
 * an alternative serialization approach when externalizing a DOM4J document.
 * Rather than serializing a document as text and re-parsing, the sax events may
 * be serialized instead.
 * </p>
 * Example usage:
 * 
 * <pre>
 * 
 *  
 *  
 *         SAXEventRecorder recorder = new SAXEventRecorder();
 *         SAXWriter saxWriter = new SAXWriter(recorder, recorder);
 *         saxWriter.write(document);
 *         out.writeObject(recorder);
 *         ...
 *         SAXEventRecorder recorder = (SAXEventRecorder)in.readObject();
 *         SAXContentHandler saxContentHandler = new SAXContentHandler();
 *         recorder.replay(saxContentHandler);
 *         Document document = saxContentHandler.getDocument();
 *  
 *   
 *  
 * </pre>
 * 
 * @author Todd Wolff (Bluestem Software)
 */
public class SAXEventRecorder extends DefaultHandler implements LexicalHandler,
        DeclHandler, DTDHandler, Externalizable {
    public static final long serialVersionUID = 1;

    private static final byte STRING = 0;

    private static final byte OBJECT = 1;

    private static final byte NULL = 2;

    private List events = new ArrayList();

    private Map prefixMappings = new HashMap();

    private static final String XMLNS = "xmlns";

    private static final String EMPTY_STRING = "";

    public SAXEventRecorder() {
    }

    public void replay(ContentHandler handler) throws SAXException {
        SAXEvent saxEvent;
        Iterator itr = events.iterator();

        while (itr.hasNext()) {
            saxEvent = (SAXEvent) itr.next();

            switch (saxEvent.event) {
                // replay to ContentHandler
                case SAXEvent.PROCESSING_INSTRUCTION:
                    handler.processingInstruction((String) saxEvent.getParm(0),
                            (String) saxEvent.getParm(1));

                    break;

                case SAXEvent.START_PREFIX_MAPPING:
                    handler.startPrefixMapping((String) saxEvent.getParm(0),
                            (String) saxEvent.getParm(1));

                    break;

                case SAXEvent.END_PREFIX_MAPPING:
                    handler.endPrefixMapping((String) saxEvent.getParm(0));

                    break;

                case SAXEvent.START_DOCUMENT:
                    handler.startDocument();

                    break;

                case SAXEvent.END_DOCUMENT:
                    handler.endDocument();

                    break;

                case SAXEvent.START_ELEMENT:

                    AttributesImpl attributes = new AttributesImpl();
                    List attParmList = (List) saxEvent.getParm(3);

                    if (attParmList != null) {
                        Iterator attsItr = attParmList.iterator();

                        while (attsItr.hasNext()) {
                            String[] attParms = (String[]) attsItr.next();
                            attributes.addAttribute(attParms[0], attParms[1],
                                    attParms[2], attParms[3], attParms[4]);
                        }
                    }

                    handler.startElement((String) saxEvent.getParm(0),
                            (String) saxEvent.getParm(1), (String) saxEvent
                                    .getParm(2), attributes);

                    break;

                case SAXEvent.END_ELEMENT:
                    handler.endElement((String) saxEvent.getParm(0),
                            (String) saxEvent.getParm(1), (String) saxEvent
                                    .getParm(2));

                    break;

                case SAXEvent.CHARACTERS:

                    char[] chars = (char[]) saxEvent.getParm(0);
                    int start = ((Integer) saxEvent.getParm(1)).intValue();
                    int end = ((Integer) saxEvent.getParm(2)).intValue();
                    handler.characters(chars, start, end);

                    break;

                // replay to LexicalHandler
                case SAXEvent.START_DTD:
                    ((LexicalHandler) handler).startDTD((String) saxEvent
                            .getParm(0), (String) saxEvent.getParm(1),
                            (String) saxEvent.getParm(2));

                    break;

                case SAXEvent.END_DTD:
                    ((LexicalHandler) handler).endDTD();

                    break;

                case SAXEvent.START_ENTITY:
                    ((LexicalHandler) handler).startEntity((String) saxEvent
                            .getParm(0));

                    break;

                case SAXEvent.END_ENTITY:
                    ((LexicalHandler) handler).endEntity((String) saxEvent
                            .getParm(0));

                    break;

                case SAXEvent.START_CDATA:
                    ((LexicalHandler) handler).startCDATA();

                    break;

                case SAXEvent.END_CDATA:
                    ((LexicalHandler) handler).endCDATA();

                    break;

                case SAXEvent.COMMENT:

                    char[] cchars = (char[]) saxEvent.getParm(0);
                    int cstart = ((Integer) saxEvent.getParm(1)).intValue();
                    int cend = ((Integer) saxEvent.getParm(2)).intValue();
                    ((LexicalHandler) handler).comment(cchars, cstart, cend);

                    break;

                // replay to DeclHandler
                case SAXEvent.ELEMENT_DECL:
                    ((DeclHandler) handler).elementDecl((String) saxEvent
                            .getParm(0), (String) saxEvent.getParm(1));

                    break;

                case SAXEvent.ATTRIBUTE_DECL:
                    ((DeclHandler) handler).attributeDecl((String) saxEvent
                            .getParm(0), (String) saxEvent.getParm(1),
                            (String) saxEvent.getParm(2), (String) saxEvent
                                    .getParm(3), (String) saxEvent.getParm(4));

                    break;

                case SAXEvent.INTERNAL_ENTITY_DECL:
                    ((DeclHandler) handler).internalEntityDecl(
                            (String) saxEvent.getParm(0), (String) saxEvent
                                    .getParm(1));

                    break;

                case SAXEvent.EXTERNAL_ENTITY_DECL:
                    ((DeclHandler) handler).externalEntityDecl(
                            (String) saxEvent.getParm(0), (String) saxEvent
                                    .getParm(1), (String) saxEvent.getParm(2));

                    break;

                default:
                    throw new SAXException("Unrecognized event: "
                            + saxEvent.event);
            }
        }
    }

    // ContentHandler interface
    // -------------------------------------------------------------------------
    public void processingInstruction(String target, String data)
            throws SAXException {
        SAXEvent saxEvent = new SAXEvent(SAXEvent.PROCESSING_INSTRUCTION);
        saxEvent.addParm(target);
        saxEvent.addParm(data);
        events.add(saxEvent);
    }

    public void startPrefixMapping(String prefix, String uri)
            throws SAXException {
        SAXEvent saxEvent = new SAXEvent(SAXEvent.START_PREFIX_MAPPING);
        saxEvent.addParm(prefix);
        saxEvent.addParm(uri);
        events.add(saxEvent);
    }

    public void endPrefixMapping(String prefix) throws SAXException {
        SAXEvent saxEvent = new SAXEvent(SAXEvent.END_PREFIX_MAPPING);
        saxEvent.addParm(prefix);
        events.add(saxEvent);
    }

    public void startDocument() throws SAXException {
        SAXEvent saxEvent = new SAXEvent(SAXEvent.START_DOCUMENT);
        events.add(saxEvent);
    }

    public void endDocument() throws SAXException {
        SAXEvent saxEvent = new SAXEvent(SAXEvent.END_DOCUMENT);
        events.add(saxEvent);
    }

    public void startElement(String namespaceURI, String localName,
            String qualifiedName, Attributes attributes) throws SAXException {
        SAXEvent saxEvent = new SAXEvent(SAXEvent.START_ELEMENT);
        saxEvent.addParm(namespaceURI);
        saxEvent.addParm(localName);
        saxEvent.addParm(qualifiedName);

        QName qName = null;
        if (namespaceURI != null) {
            qName = new QName(localName, Namespace.get(namespaceURI));
        } else {
            qName = new QName(localName);
        }

        if ((attributes != null) && (attributes.getLength() > 0)) {
            List attParmList = new ArrayList(attributes.getLength());
            String[] attParms = null;

            for (int i = 0; i < attributes.getLength(); i++) {

                String attLocalName = attributes.getLocalName(i);

                if (attLocalName.startsWith(XMLNS)) {

                    // if SAXWriter is writing a DOMDocument, namespace
                    // decls are treated as attributes. record a start
                    // prefix mapping event
                    String prefix = null;
                    if (attLocalName.length() > 5) {
                        prefix = attLocalName.substring(6);
                    } else {
                        prefix = EMPTY_STRING;
                    }

                    SAXEvent prefixEvent = new SAXEvent(