nodeimpl.java

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 /*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sun.org.apache.xerces.internal.dom;

import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Hashtable;

import org.w3c.dom.UserDataHandler;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.events.Event;
import org.w3c.dom.events.EventListener;
import org.w3c.dom.events.EventTarget;

/**
 * NodeImpl provides the basic structure of a DOM tree. It is never used
 * directly, but instead is subclassed to add type and data
 * information, and additional methods, appropriate to each node of
 * the tree. Only its subclasses should be instantiated -- and those,
 * with the exception of Document itself, only through a specific
 * Document's factory methods.
 * <P>
 * The Node interface provides shared behaviors such as siblings and
 * children, both for consistancy and so that the most common tree
 * operations may be performed without constantly having to downcast
 * to specific node types. When there is no obvious mapping for one of
 * these queries, it will respond with null.
 * Note that the default behavior is that children are forbidden. To
 * permit them, the subclass ParentNode overrides several methods.
 * <P>
 * NodeImpl also implements NodeList, so it can return itself in
 * response to the getChildNodes() query. This eliminiates the need
 * for a separate ChildNodeList object. Note that this is an
 * IMPLEMENTATION DETAIL; applications should _never_ assume that
 * this identity exists.
 * <P>
 * All nodes in a single document must originate
 * in that document. (Note that this is much tighter than "must be
 * same implementation") Nodes are all aware of their ownerDocument,
 * and attempts to mismatch will throw WRONG_DOCUMENT_ERR.
 * <P>
 * However, to save memory not all nodes always have a direct reference
 * to their ownerDocument. When a node is owned by another node it relies
 * on its owner to store its ownerDocument. Parent nodes always store it
 * though, so there is never more than one level of indirection.
 * And when a node doesn't have an owner, ownerNode refers to its
 * ownerDocument.
 * <p>
 * This class doesn't directly support mutation events, however, it still
 * implements the EventTarget interface and forward all related calls to the
 * document so that the document class do so.
 * 
 * @xerces.internal
 *
 * @author Arnaud  Le Hors, IBM
 * @author Joe Kesselman, IBM
 * @version $Id: NodeImpl.java,v 1.2.6.1 2005/08/31 12:27:09 sunithareddy Exp $
 * @since  PR-DOM-Level-1-19980818.
 */
public abstract class NodeImpl
    implements Node, NodeList, EventTarget, Cloneable, Serializable{

    //
    // Constants
    //


    // TreePosition Constants.
    // Taken from DOM L3 Node interface.
    /**
     * The node precedes the reference node.
     */
    public static final short TREE_POSITION_PRECEDING   = 0x01;
    /**
     * The node follows the reference node.
     */
    public static final short TREE_POSITION_FOLLOWING   = 0x02;
    /**
     * The node is an ancestor of the reference node.
     */
    public static final short TREE_POSITION_ANCESTOR    = 0x04;
    /**
     * The node is a descendant of the reference node.
     */
    public static final short TREE_POSITION_DESCENDANT  = 0x08;
    /**
     * The two nodes have an equivalent position. This is the case of two 
     * attributes that have the same <code>ownerElement</code>, and two 
     * nodes that are the same.
     */
    public static final short TREE_POSITION_EQUIVALENT  = 0x10;
    /**
     * The two nodes are the same. Two nodes that are the same have an 
     * equivalent position, though the reverse may not be true.
     */
    public static final short TREE_POSITION_SAME_NODE   = 0x20;
    /**
     * The two nodes are disconnected, they do not have any common ancestor. 
     * This is the case of two nodes that are not in the same document.
     */
    public static final short TREE_POSITION_DISCONNECTED = 0x00;


    // DocumentPosition
    public static final short DOCUMENT_POSITION_DISCONNECTED = 0x01;
    public static final short DOCUMENT_POSITION_PRECEDING = 0x02;
    public static final short DOCUMENT_POSITION_FOLLOWING = 0x04;
    public static final short DOCUMENT_POSITION_CONTAINS = 0x08;
    public static final short DOCUMENT_POSITION_IS_CONTAINED = 0x10;
    public static final short DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC = 0x20;

    /** Serialization version. */
    static final long serialVersionUID = -6316591992167219696L;

    // public

    /** Element definition node type. */
    public static final short ELEMENT_DEFINITION_NODE = 21;

    //
    // Data
    //

    // links

    protected NodeImpl ownerNode; // typically the parent but not always!

    // data

    protected short flags;

    protected final static short READONLY     = 0x1<<0;
    protected final static short SYNCDATA     = 0x1<<1;
    protected final static short SYNCCHILDREN = 0x1<<2;
    protected final static short OWNED        = 0x1<<3;
    protected final static short FIRSTCHILD   = 0x1<<4;
    protected final static short SPECIFIED    = 0x1<<5;
    protected final static short IGNORABLEWS  = 0x1<<6;
    protected final static short HASSTRING    = 0x1<<7;
    protected final static short NORMALIZED = 0x1<<8;
    protected final static short ID           = 0x1<<9;

    //
    // Constructors
    //

    /**
     * No public constructor; only subclasses of Node should be
     * instantiated, and those normally via a Document's factory methods
     * <p>
     * Every Node knows what Document it belongs to.
     */
    protected NodeImpl(CoreDocumentImpl ownerDocument) {
        // as long as we do not have any owner, ownerNode is our ownerDocument
        ownerNode = ownerDocument;
    } // <init>(CoreDocumentImpl)

    /** Constructor for serialization. */
    public NodeImpl() {}

    //
    // Node methods
    //

    /**
     * A short integer indicating what type of node this is. The named
     * constants for this value are defined in the org.w3c.dom.Node interface.
     */
    public abstract short getNodeType();

    /**
     * the name of this node.
     */
    public abstract String getNodeName();
    
    /**
     * Returns the node value.
     * @throws DOMException(DOMSTRING_SIZE_ERR)
     */
    public String getNodeValue()
        throws DOMException {
        return null;            // overridden in some subclasses
    }

    /**
     * Sets the node value.
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR)
     */
    public void setNodeValue(String x) 
        throws DOMException {
        // Default behavior is to do nothing, overridden in some subclasses
    }

    /**
     * Adds a child node to the end of the list of children for this node.
     * Convenience shorthand for insertBefore(newChild,null).
     * @see #insertBefore(Node, Node)
     * <P>
     * By default we do not accept any children, ParentNode overrides this.
     * @see ParentNode
     *
     * @return newChild, in its new state (relocated, or emptied in the case of
     * DocumentNode.)
     *
     * @throws DOMException(HIERARCHY_REQUEST_ERR) if newChild is of a
     * type that shouldn't be a child of this node.
     *
     * @throws DOMException(WRONG_DOCUMENT_ERR) if newChild has a
     * different owner document than we do.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node appendChild(Node newChild) throws DOMException {
    	return insertBefore(newChild, null);
    }

    /**
     * Returns a duplicate of a given node. You can consider this a
     * generic "copy constructor" for nodes. The newly returned object should
     * be completely independent of the source object's subtree, so changes
     * in one after the clone has been made will not affect the other.
     * <P>
     * Note: since we never have any children deep is meaningless here,
     * ParentNode overrides this behavior.
     * @see ParentNode
     *
     * <p>
     * Example: Cloning a Text node will copy both the node and the text it
     * contains.
     * <p>
     * Example: Cloning something that has children -- Element or Attr, for
     * example -- will _not_ clone those children unless a "deep clone"
     * has been requested. A shallow clone of an Attr node will yield an
     * empty Attr of the same name.
     * <p>
     * NOTE: Clones will always be read/write, even if the node being cloned
     * is read-only, to permit applications using only the DOM API to obtain
     * editable copies of locked portions of the tree.
     */
    public Node cloneNode(boolean deep) {

        if (needsSyncData()) {
            synchronizeData();
	}
    	
    	NodeImpl newnode;
    	try {
            newnode = (NodeImpl)clone();
    	}
    	catch (CloneNotSupportedException e) {
            // if we get here we have an error in our program we may as well
            // be vocal about it, so that people can take appropriate action.
            throw new RuntimeException("**Internal Error**" + e);
    	}
    	
        // Need to break the association w/ original kids
    	newnode.ownerNode      = ownerDocument();
        newnode.isOwned(false);

        // By default we make all clones readwrite,
        // this is overriden in readonly subclasses
        newnode.isReadOnly(false);

        ownerDocument().callUserDataHandlers(this, newnode,
                                             UserDataHandler.NODE_CLONED);

    	return newnode;

    } // cloneNode(boolean):Node

    /**
     * Find the Document that this Node belongs to (the document in
     * whose context the Node was created). The Node may or may not
     * currently be part of that Document's actual contents.
     */
    public Document getOwnerDocument() {
        // if we have an owner simply forward the request
        // otherwise ownerNode is our ownerDocument
        if (isOwned()) {
            return ownerNode.ownerDocument();
        } else {
            return (Document) ownerNode;
        }
    }

    /**
     * same as above but returns internal type and this one is not overridden
     * by CoreDocumentImpl to return null 
     */
    CoreDocumentImpl ownerDocument() {
        // if we have an owner simply forward the request
        // otherwise ownerNode is our ownerDocument
        if (isOwned()) {
            return ownerNode.ownerDocument();
        } else {
            return (CoreDocumentImpl) ownerNode;
        }
    }

    /**
     * NON-DOM
     * set the ownerDocument of this node
     */
    void setOwnerDocument(CoreDocumentImpl doc) {
        if (needsSyncData()) {
            synchronizeData();
        }
        // if we have an owner we rely on it to have it right
        // otherwise ownerNode is our ownerDocument
	if (!isOwned()) {
            ownerNode = doc;
        }
    }

    /**
     * Returns the node number
     */