namednodemapimpl.java

Java的面向对象数据库系统的源代码

/**
 * org/ozone-db/xml/dom/NamedNodeMapImpl.java
 *
 * The contents of this file are subject to the OpenXML Public
 * License Version 1.0; you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 * http://www.openxml.org/license.html
 *
 * THIS SOFTWARE IS DISTRIBUTED ON AN "AS IS" BASIS WITHOUT WARRANTY
 * OF ANY KIND, EITHER EXPRESSED OR IMPLIED. THE INITIAL DEVELOPER
 * AND ALL CONTRIBUTORS SHALL NOT BE LIABLE FOR ANY DAMAGES AS A
 * RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. SEE THE LICENSE FOR THE SPECIFIC LANGUAGE GOVERNING
 * RIGHTS AND LIMITATIONS UNDER THE LICENSE.
 *
 * The Initial Developer of this code under the License is Assaf Arkin.
 * Portions created by Assaf Arkin are Copyright (C) 1998, 1999.
 * All Rights Reserved.
 */

/**
 * Changes for Persistent DOM running with ozone are
 * Copyright 1999 by SMB GmbH. All rights reserved.
 */

package org.ozoneDB.xml.dom;

import java.util.*;
import java.io.*;
import org.w3c.dom.*;
import org.ozoneDB.OzoneObject;


/**
 * Implements a collection of nodes that can be accessed by name. Used mostly by
 * {@link DocumentTypeImpl} to hold collections of element, notation and other
 * definitions.
 * <P>
 * The actual collection of objects is held by some owner node in a {@link
 * java.util.Dictionary}. This map object provides access to this dictionary
 * in a manner that is consistent with the DOM. This map can be accessed
 * concurrently, so the owner need only create one map per dictionary.
 * <P>
 * Nodes are not maintained in any particular order, so accessing them by index
 * can be expected to be a slow operation.
 *
 *
 * @version $Revision: 1.2 $ $Date: 2003/11/20 23:18:42 $
 * @author <a href="mailto:[e-mail]">Assaf Arkin</a>
 * @see org.w3c.dom.NamedNodeMap
 */
public final class NamedNodeMapImpl extends OzoneObject implements NamedNodeMapProxy, Externalizable {

    final static long serialVersionUID = 1;


    public Node getNamedItemNS( java.lang.String namespaceURI, java.lang.String localName ) {
        throw new DOMExceptionImpl( DOMException.NOT_SUPPORTED_ERR,
                "NamedNode.getNamedItemNS(): ozone's persistent DOM doesn't support DOM level 2 yet." );
    }


    public Node setNamedItemNS( Node arg ) throws DOMException {
        throw new DOMExceptionImpl( DOMException.NOT_SUPPORTED_ERR,
                "NamedNode.getNamedItemNS(): ozone's persistent DOM doesn't support DOM level 2 yet." );
    }


    public Node removeNamedItemNS( java.lang.String namespaceURI, java.lang.String localName ) throws DOMException {
        throw new DOMExceptionImpl( DOMException.NOT_SUPPORTED_ERR,
                "NamedNode.getNamedItemNS(): ozone's persistent DOM doesn't support DOM level 2 yet." );
    }


    public synchronized Node getNamedItem( String name ) {
        // Dictionary get by name.
        return (Node)_dictionary.get( name );
    }


    public synchronized Node setNamedItem( Node arg ) throws DOMException {
        // Make sure the DTD is not read only and that the added node is of the
        // allowed type (Entity, Notation, AttrDecl, ElementDecl).
        if (_owner.isReadOnly()) {
            throw new DOMExceptionImpl( DOMException.NO_MODIFICATION_ALLOWED_ERR );
        }
        if (arg == null || !(arg instanceof Node)) {
            throw new DOMExceptionImpl( DOMException.WRONG_DOCUMENT_ERR );
        }
        if (!(arg instanceof ElementDeclProxy || arg instanceof Notation || arg instanceof Entity)) {
            throw new DOMExceptionImpl( DOMException.WRONG_DOCUMENT_ERR );
        }
        return (Node)_dictionary.put( arg.getNodeName(), arg );
    }


    public synchronized Node removeNamedItem( String name ) throws DOMException {
        if (_owner.isReadOnly()) {
            throw new DOMExceptionImpl( DOMException.NO_MODIFICATION_ALLOWED_ERR );
        }
        return (Node)_dictionary.remove( name );
    }


    public synchronized Node item( int index ) {
        Enumeration elem;

        // Get by index is a long operation, but one that is performed less
        // than get by name. We opt not to use the JDK 1.2 collections to
        // speed it up for the sake of portability.
        elem = _dictionary.elements();
        while (elem.hasMoreElements()) {
            if (index == 0) {
                return (Node)elem.nextElement();
            }
            elem.nextElement();
            --index;
        }
        return null;
    }


    public int getLength() {
        return _dictionary.size();
    }


    /**
     * So we lied about the owner managing the dictionary. But just in case
     * the owner would like to traverse the dictionary list without resorting
     * to the slower indexed method.
     *
     * @return Enumeration of all elements in the dictionary
     */
    public Enumeration elements() {
        return _dictionary.elements();
    }


    /**
     * Constructor required the owner of this dictionary and a reference to the
     * dictionary. Once constructed, the map is ready for use.
     *
     * @param owner The owner of this dictionary
     * @param dictionary The dictionary managed by that owner
     */
    public NamedNodeMapImpl( NodeProxy owner, Dictionary dictionary ) {
        init( owner, dictionary );
    }


    public NamedNodeMapImpl() {
        super();
    }


    public void init( NodeProxy owner, Dictionary dictionary ) {
        if (owner == null || dictionary == null) {
            throw new NullPointerException( "Argument 'owner' or 'dictionary' is null." );
        }
        _dictionary = dictionary;
        _owner = owner;
    }


    /** */
    public void writeExternal( ObjectOutput out ) throws IOException {
        // super.writeExternal (out);
        out.writeObject( _dictionary );
        out.writeObject( _owner );
    }


    /** */
    public void readExternal( ObjectInput in ) throws IOException, ClassNotFoundException {
        // super.readExternal (in);
        _dictionary = (Dictionary)in.readObject();
        _owner = (NodeProxy)in.readObject();
    }

    /**
     * Reference to the dictionary accessed through this node map. The dictionary
     * is not held by this object but by the {@link #_owner}.
     */
    private Dictionary _dictionary;


    /**
     * Reference to the owner of this node list. This is another node which contains
     * {@link #_dictionary} as part of it.
     */
    private NodeProxy _owner;
}