elementimpl.java

用Java写的面相对象的数据库管理系统

/**
 * org/ozone-db/xml/dom/ElementImpl.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.*;


/**
 * The most common node type, {@link org.w3c.dom.Element} inherits the generic
 * {@link Node} interface and adds support for retrieving and setting attributes
 * either as nodes or as strings.
 * <P>
 * Notes:
 * <OL>
 * <LI>Node type is {@link org.w3c.dom.Node#ELEMENT_NODE}
 * <LI>Node supports childern
 * <LI>Node has no value
 * <LI>Node has attributes
 * </OL>
 * <P>
 * To speed up implementation, all attributes are implemented as double-linked
 * list implemented using {@link NodeImpl#_parent}, {@link NodeImpl#_nextNode} and
 * {@link NodeImpl#_prevNode}. This support is provided to through {@link
 * #getNamedAttr}, {@link #appendAttr} and {@link #removeAttr} methods.
 *
 *
 * @version $Revision: 1.27 $ $Date: 2000/11/10 17:48:07 $
 * @author <a href="mailto:[e-mail]">Assaf Arkin</a>
 * @see org.w3c.dom.Element
 * @see org.w3c.dom.Attr
 * @see org.w3c.dom.NamedNodeMap
 * @see AttrImpl
 */
public class ElementImpl extends NodeImpl implements ElementProxy, Externalizable {
    
    final static long serialVersionUID = 1;
    
    
    public Node getNamedItemNS( java.lang.String namespaceURI, java.lang.String localName ) {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public Node setNamedItemNS( Node arg ) throws DOMException {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "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 DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public Attr getAttributeNodeNS( java.lang.String namespaceURI, java.lang.String localName ) {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public Attr setAttributeNodeNS( Attr newAttr ) throws DOMException {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public java.lang.String getAttributeNS( java.lang.String namespaceURI, java.lang.String localName ) {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public void setAttributeNS( java.lang.String namespaceURI, java.lang.String qualifiedName, java.lang.String value ) 
            throws DOMException {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public void removeAttributeNS( java.lang.String namespaceURI, java.lang.String localName ) throws DOMException {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public NodeList getElementsByTagNameNS( java.lang.String namespaceURI, java.lang.String localName ) {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    } 
    
    
    public boolean hasAttributes() {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    }
    
    
    public boolean hasAttribute( String name ) {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    }
    
    
    public boolean hasAttributeNS( String namespaceURI, String localname ) {
        throw new DOMException( DOMException.NOT_SUPPORTED_ERR,
                "ozone's persistent DOM doesn't support DOM level 2 yet." );
    }
    
    
    public final short getNodeType() {
        return ELEMENT_NODE;
    } 
    
    
    public final Enumeration elements() {
        return (Enumeration)null;
    } 
    
    
    public void setFirstAttr( Attr attribute ) {
        _firstAttr = (AttrProxy)attribute;
    } 
    
    
    public void setLastAttr( Attr attribute ) {
        _lastAttr = (AttrProxy)attribute;
    } 
    
    
    public void setAttrCount( int count ) {
        _attrCount = count;
    } 
    
    
    /**
     * Returns the name of the tag, same as calling {@link #getNodeName}.
     * In XML documents, the return value preserves case. In HTML documents,
     * the return value is always upper case regardless of the original value.
     *
     * @return Tag name
     */
    public final String getTagName() {
        return getNodeName();
    } 
    
    
    public final void setNodeValue( String value ) {
        throw new DOMExceptionImpl( DOMException.NO_DATA_ALLOWED_ERR, "This node type does not support values." );
    } 
    
    
    /**
     * Returns a list of elements extracted based on their tag name (or all of
     * them if the tag name is "*"). The returned list is a snapshot of the
     * element's contents at the time of calling. Subsequent updates to the
     * element are not reflected in the list. This might result in inaccuracies
     * when working from multiple threads.
     *
     * @param tagName The element tag name to look for or "*" for all elements
     * @return A snapshot of the named elements contained within this element
     */
    public synchronized final NodeList getElementsByTagName( String tagName ) {
        // The full implementation can be found in ElementListImpl
        return (NodeList)new org.ozoneDB.xml.dom.ElementListImpl( this, tagName );
    } 
    
    
    public synchronized final void normalize() {
        Node node;
        Node next;
        
        // Run through all child nodes of this element. If a particular child
        // is an Element, normalize it. If a particular child is a Text and is
        // followed by a second Text node, concatenate the data from the second
        // to the first and remove the second node.
        node = getFirstChild();
        while (node != null) {
            if (node instanceof ElementProxy) {
                ((ElementProxy)node).normalize();
            } else {
                if (node instanceof TextProxy) {
                    next = node.getNextSibling();
                    while (next != null && next instanceof TextProxy) {
                        ((TextProxy)node).appendData( ((TextProxy)next).getData() );
                        removeChild( next );
                        next = node.getNextSibling();
                    } 
                } 
            } 
            node = node.getNextSibling();
        } 
    } 
    
    
    public final NamedNodeMap getAttributes() {
        // This is a NamedNodeMap of all its attributes.
        // return this;
        return (NamedNodeMap)self();
    } 
    
    
    public synchronized final String getAttribute( String name ) {
        AttrProxy attr;
        
        // Look for the named attribute and return it's value.
        attr = (AttrProxy)getNamedAttr( name );
        if (attr == null) {
            return "";
        } 
        return attr.getValue();
    } 
    
    
    public synchronized final void setAttribute( String name, String value ) throws DOMException {
        AttrProxy attr;
        
        if (isReadOnly()) {
            throw new DOMExceptionImpl( DOMException.NO_MODIFICATION_ALLOWED_ERR );
        } 
        // If attribute value is null, might as well remove attribute. This will
        // either save space, or return the default value instead.
        if (value == null) {
            removeAttribute( name );
        } else {
            try {
                // Get the named attribute and change it's value. If the attribute
                // does not exist, create a new attribute by that name and add it.
                // Call setValue() to assure correct behavior.
                attr = (AttrProxy)getNamedAttr( name );
                if (attr == null) {
                    attr = (AttrProxy)database().createObject( AttrImpl.class.getName() );
                    attr.init( _ownerDocument, name, "" );
                    appendAttr( attr );
                } 
                attr.setValue( value );
            } catch (Exception except) {
                throw new DOMExceptionImpl( DOMExceptionImpl.PDOM_ERR, except.getMessage() );
            } 
        } 
    } 
    
    
    public synchronized final void removeAttribute( String name ) {
        AttrProxy attr;
        
        attr = (AttrProxy)getNamedAttr( name );
        if (attr != null) {
            removeAttr( attr );
        } 
    } 
    
    
    public final Attr getAttributeNode( String name ) {
        return getNamedAttr( name );
    } 
    
    
    public synchronized final Attr setAttributeNode( Attr newAttr ) throws DOMException {
        AttrProxy oldAttr;
        
        if (isReadOnly()) {
            throw new DOMExceptionImpl( DOMException.NO_MODIFICATION_ALLOWED_ERR );
        } 
        if (newAttr == null || !(newAttr instanceof AttrProxy)) {
            throw new DOMExceptionImpl( DOMException.WRONG_DOCUMENT_ERR );
        } 
        // Note: getParentNode() will return null.
        if (((AttrProxy)newAttr).getParentNode() != null) {
            throw new DOMExceptionImpl( DOMException.INUSE_ATTRIBUTE_ERR );
        } 
        synchronized (newAttr) {
            oldAttr = (AttrProxy)getNamedAttr( newAttr.getName() );
            if (oldAttr != null) {
                removeAttr( oldAttr );
            } 
            appendAttr( (AttrProxy)newAttr );
        } 
        return oldAttr;
    } 
    
    
    public synchronized final Attr removeAttributeNode( Attr oldAttr ) {
        if (isReadOnly()) {
            throw new DOMExceptionImpl( DOMException.NO_MODIFICATION_ALLOWED_ERR );
        } 
        if (!(oldAttr instanceof Attr)) {
            throw new DOMExceptionImpl( DOMException.HIERARCHY_REQUEST_ERR,
                    "Node is not an attribute compatible with this element." );
        } 
        oldAttr = removeAttr( (AttrProxy)oldAttr );
        if (oldAttr == null) {
            throw new DOMExceptionImpl( DOMException.NOT_FOUND_ERR );
        } 
        return oldAttr;
    } 
    
    
    public synchronized final Node getNamedItem( String name ) {
        return getNamedAttr( name );
    } 
    
    
    public final Node setNamedItem( Node arg ) throws DOMException {
        if (!(arg instanceof AttrProxy)) {
            throw new DOMExceptionImpl( DOMException.HIERARCHY_REQUEST_ERR,
                    "Node is not an attribute compatible with this element." );
        } 
        return setAttributeNode( (AttrProxy)arg );
    } 
    
    
    public synchronized final Node removeNamedItem( String name ) throws DOMException {
        AttrProxy attr;
        
        attr = (AttrProxy)getNamedAttr( name );