xmlcontainerhelperimpl.java

Java的面向对象数据库系统的源代码

// You can redistribute this software and/or modify it under the terms of
// the Ozone Library License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-@year@ by SMB GmbH. All rights reserved.
//
// $Id$

package org.ozoneDB.xml.util;

import java.io.IOException;



import org.w3c.dom.Document;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;



import org.xml.sax.SAXException;



import org.ozoneDB.OzoneObject;

import org.ozoneDB.xml.dom.DocumentProxy;



import org.infozone.tools.xml.queries.XObject;

import org.infozone.tools.xml.queries.XPathQuery;

import org.infozone.tools.xml.queries.XUpdateQuery;

import org.infozone.tools.xml.queries.XPathQueryFactory;

import org.infozone.tools.xml.queries.XUpdateQueryFactory;


/**
 * This class provides the server side part of the XMLContainer. It mainly
 * handles storing and retrieving of parts of the underlying XML document.
 *
 * @version $Revision$ $Date$
 * @author <a href="http://www.smb-tec.com">SMB</a>
 */
public final class XMLContainerHelperImpl
             extends OzoneObject
             implements XMLContainerHelper {

    private static final long serialVersionUID = 4L;

    private static final boolean debug = XMLContainer.debug;

    private static XPathQueryFactory xpathQueryFactory;

    private static XUpdateQueryFactory xupdateQueryFactory;

    /** The underlying XML document. */
    private Document document;

    static {
        // use Xt and Lexus for XPath and XUpdate
        if (System.getProperties().get( "org.infozone.tools.xml.queries.XPathQueryFactory" ) == null) {
            System.getProperties().put( "org.infozone.tools.xml.queries.XPathQueryFactory",
                                        "org.infozone.tools.xml.queries.xt.XPathQueryFactoryImpl");
        }
        if (System.getProperties().get( "org.infozone.tools.xml.queries.XUpdateQueryFactory" ) == null ) {
            System.getProperties().put( "org.infozone.tools.xml.queries.XUpdateQueryFactory",
                                        "org.infozone.lexus.XUpdateQueryFactoryImpl");
        }

        xpathQueryFactory = XPathQueryFactory.newInstance();
        xupdateQueryFactory = XUpdateQueryFactory.newInstance();
    }

    public XMLContainerHelperImpl() {
        if (debug) {
            System.out.println( "helper: ctor..." );
        }
    }

    public final void onCreate() {
        if (debug) {
            System.out.println( "helper: onCreate()..." );
        }
        document = (Document)database().createObject( org.ozoneDB.xml.dom.DocumentImpl.class.getName() );
        ((DocumentProxy)document).setContainer( this );
    }

    public final void onDelete() {
        if (debug) {
            System.out.println( "helper: onDelete()..." );
        }
        clearDocument();
    }

    public void clearDocument() {
        // FIXME: this is what we should do but that does not work
        // for some strange reason
        //Node pNode = getDocument();
        //((DocumentProxy)pNode).clearDocument();

        // HACK: just create a new Document instead
        if (document != null) {
            database().deleteObject( (DocumentProxy)document );
        }
        document = (Document)database().createObject( org.ozoneDB.xml.dom.DocumentImpl.class.getName() );
    }

    public final void setDocument( Document _pdoc ) {
        if (debug) {
            System.out.println( "helper: setDocument..." );
        }

        if (document != null) {
            throw new IllegalStateException( "Container helper is already assigned to a document." );
        }

        document = _pdoc;
        ((DocumentProxy)document).setContainer( this );
    }

    public final Document getDocument() {
        if (debug) {
            System.out.println( "helper: getDocument..." );
        }
        return document;
    }

    public final SAXChunkConsumer beginInputSequence( Node _pNode ) throws Exception {
        if (debug) {
            System.out.println("helper: beginInputSequence...");
        }
        if (_pNode == null) {
            clearDocument();
        }
        SAXChunkConsumer consumer = new SAXChunkConsumer( getDocument(), _pNode );
        return consumer;
    }

    public final SAXChunkConsumer putChunk( byte[] _chunkData, SAXChunkConsumer _consumer )
            throws SAXException, IOException {
        _consumer.processChunk( _chunkData );
        return _consumer;
    }

    public final void endInputSequence() throws Exception {
        if (debug) {
            System.out.println( "helper: endInputSequence..." );
        }
    }

/*    public final SAXChunkProducer beginOutputSequence( Node _pnode, int _depth ) throws Exception {
        if (_pnode == null) {
            _pnode = getDocument();
        }
        ModifiableNodeList mnl = new ModifiableNodeList(1);
        mnl.addNode(_pnode);
        return new SAXChunkProducer( mnl, _depth );
    }
*/
    public final SAXChunkProducer beginOutputSequence( NodeList _pnodes, int _depth ) throws Exception {
        if (_pnodes == null) {
            _pnodes = new ModifiableNodeList(1);
            ((ModifiableNodeList)_pnodes).addNode(getDocument());
        }
        return new SAXChunkProducer( _pnodes, _depth );
    }

    public final SAXChunkProducer createNextChunk( SAXChunkProducer producer ) throws SAXException {
        producer.createNextChunk();
        return producer;
    }

    public final void endOutputSequence() throws Exception {
        if (debug) {
            System.out.println( "helper: endOutputSequence..." );
        }
    }

    public final XObject executeXPath( OzoneXPathQuery _query ) throws Exception {
        if (_query.rootNode == null) {
            _query.rootNode = getDocument();
        }
        XPathQuery query = xpathQueryFactory.newXPathQuery();
        query.setQString( _query.qstring );
        if (_query.filter != null) {
            query.setNodeFilter( _query.filter );
        }
        if (_query.namespace != null) {
            query.setNamespace( _query.namespace );
        }
        return query.execute( _query.rootNode );
    }

    public final void executeXUpdate( OzoneXUpdateQuery _query ) throws Exception {
        if (_query.rootNode == null) {
            _query.rootNode = getDocument();
        }
        XUpdateQuery query = xupdateQueryFactory.newXUpdateQuery();
        query.setQString( _query.qstring );
        if (_query.filter != null) {
            query.setNodeFilter( _query.filter );
        }
        if (_query.namespace != null) {
            query.setNamespace( _query.namespace );
        }
        System.out.println( query.getClass().getName() );
        System.out.println( _query.qstring );
        System.out.println( _query.rootNode );
        query.execute( _query.rootNode );
    }

    /**
     * Determines the absolute XPath for the given node.
     * @param _pnode The W3C DOM node whose XPath is to determine.
     * @return The string representing the absolute XPath for this node.
     */
    public final String xpathForNode( Node _pnode ) {
        if (_pnode == null) {
            throw new IllegalArgumentException( "_pnode == null." );
        }
        StringBuffer xpath = new StringBuffer();
        xpath = iterateBack( _pnode, xpath );
        return xpath.toString();
    }

    // internal stuff

    private final StringBuffer iterateBack( Node node, StringBuffer buffer ) {
        int nthChild = 1;
        String nodeName = node.getNodeName();
        Node prevNode = node;
        while ((prevNode = prevNode.getPreviousSibling()) != null) {
            if (prevNode.getNodeName().equals( nodeName ) && prevNode.getNodeType() == node.getNodeType()) {
                nthChild++;
            }
        }
        if (node.getNodeType() == Node.TEXT_NODE) {
            nodeName = "text()";
        } else if (node.getNodeType() == Node.COMMENT_NODE) {
            nodeName = "comment()";
        } else {
            if (node.getNodeType() == Node.DOCUMENT_NODE) {
                nodeName = "";
            }
        }
        buffer.insert( 0, "/" + nodeName + (nodeName.length() > 0 ? "[" + nthChild + "]" : "") );
        node = node.getParentNode();
        if (node != null && node.getNodeType() != Node.DOCUMENT_NODE) {
            buffer = iterateBack( node, buffer );
        }
        return buffer;
    }
}