ozonexpathquery.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: OzoneXPathQuery.java,v 1.1 2003/11/02 17:26:15 per_nyfelt Exp $

package org.ozoneDB.xml.util;

import java.io.*;

import org.w3c.dom.Node;
import org.w3c.dom.traversal.NodeFilter;
import org.infozone.tools.xml.queries.XObject;
import org.infozone.tools.xml.queries.XPathQuery;

/**
 * This class represents a XPath that can be used to query the document of
 * a {@link XMLContainer}.
 *
 * @version $Revision: 1.1 $ $Date: 2003/11/02 17:26:15 $
 * @author <a href="http://www.softwarebuero.de">SMB</a>
 * @see XMLContainer
 */
public final class OzoneXPathQuery implements XPathQuery, Externalizable {

    protected final static long serialVersionUID = 1L;

    protected String qstring;

    protected NodeFilter filter;

    protected Node namespace;

    protected Node rootNode;

    protected transient XMLContainer delegate;

    public OzoneXPathQuery() {
    }

    protected OzoneXPathQuery(XMLContainer _delegate) {
        delegate = _delegate;
    }

    public void setQString(String _qstring) throws Exception {
        qstring = _qstring;
    }

    public void setNamespace(Node _namespace) throws Exception {
        namespace = _namespace;
    }

    public void setNodeFilter(NodeFilter _filter) throws Exception {
        filter = _filter;
    }

    /**
     * Execute the xpath.
     *
     * @see #execute(Node)
     */
    public XObject execute() throws Exception {
        return execute(null);
    }

    /**
     * Execute the xpath.
     *
     * @param _rootNode The node from which the query should start. A value of
     *     null specifies that the entire document should be searched.
     * @return The XObject insulating the query result.
     */
    public XObject execute(Node _rootNode) throws Exception {
        rootNode = _rootNode;
        return delegate.executeXPath(this);
    }

    public void writeExternal(ObjectOutput out) throws IOException {
        out.writeObject(rootNode);
        out.writeObject(qstring);
        out.writeObject(filter);
        out.writeObject(namespace);
    }

    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
        rootNode = (Node) in.readObject();
        qstring = (String) in.readObject();
        filter = (NodeFilter) in.readObject();
        namespace = (Node) in.readObject();
    }
}