src/whiteboard/org/apache/xerces/tree/ElementNode.java - xerces2-j - Git at Google

 /*
  * $Id$
  *
  * The Apache Software License, Version 1.1
  *
  *
  * Copyright (c) 2000 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. The end-user documentation included with the redistribution,
  *    if any, must include the following acknowledgment:
  *       "This product includes software developed by the
  *        Apache Software Foundation (http://www.apache.org/)."
  *    Alternately, this acknowledgment may appear in the software itself,
  *    if and wherever such third-party acknowledgments normally appear.
  *
  * 4. The names "Crimson" and "Apache Software Foundation" must
  *    not be used to endorse or promote products derived from this
  *    software without prior written permission. For written
  *    permission, please contact apache@apache.org.
  *
  * 5. Products derived from this software may not be called "Apache",
  *    nor may "Apache" appear in their name, without prior written
  *    permission of the Apache Software Foundation.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  * ====================================================================
  *
  * This software consists of voluntary contributions made by many
  * individuals on behalf of the Apache Software Foundation and was
  * originally based on software copyright (c) 1999, Sun Microsystems, Inc.,
  * http://www.sun.com.  For more information on the Apache Software
  * Foundation, please see <http://www.apache.org/>.
  */

 package org.apache.xerces.tree;

 import java.io.CharArrayWriter;
 import java.io.IOException;
 import java.io.Writer;

 import java.util.Enumeration;

 import org.apache.xerces.tree.XmlNames;

 import org.w3c.dom.*;


 /**
  * This class represents XML elements in a parse tree, and is often
  * subclassed to add custom behaviors.  When an XML Document object
  * is built using an <em>XmlDocumentBuilder</em> instance, simple
  * declarative configuration information may be used to control whether
  * this class, or some specialized subclass (e.g. supporting HTML DOM
  * methods) is used for elements in the resulting tree.
  *
  * <P> As well as defining new methods to provide behaviors which are
  * specific to application frameworks, such as Servlets or Swing, such
  * subclasses may also override methods such as <em>doneParse</em>
  * and <em>appendChild</em> to perform some kinds of processing during
  * tree construction.  Such processing can include transforming tree
  * structure to better suit the needs of a given application.  When
  * such transformation is done, the <em>XmlWritable</em> methods
  * may need to be overridden to make elements transform themselves back
  * to XML without losing information.  (One common transformation is
  * eliminating redundant representations of data; attributes of an XML
  * element may correspond to defaultable object properties, and so on.)
  *
  * <P> Element nodes also support a single <em>userObject</em> property,
  * which may be used to bind objects to elements where subclassing is
  * either not possible or is inappropriate.  For example, user interface
  * objects often derive from <code>java.awt.Component</code>, so that
  * they can't extend a different class (<em>ElementNode</em>).
  *
  * @see XmlDocumentBuilder
  *
  * @author David Brownell
  * @version $Revision$
  */
 public class ElementNode extends NamespacedNode implements ElementEx
 {
     private AttributeSet	attributes;
     private String		idAttributeName;
     private Object		userObject;

     private static final char	tagStart [] = { '<', '/' };
     private static final char	tagEnd [] = { ' ', '/', '>' };
     private static final String
         DEFAULT_XML_NS_URI = "http://www.w3.org/XML/1998/namespace";

     /**
      * Partially constructs an element; its tag will be assigned
      * by the factory (or subclass), while attributes and the
      * parent (and implicitly, siblings) will assigned when it is
      * joined to a DOM document.
      */
     public ElementNode () { }

     public ElementNode(String namespaceURI, String qualifiedName)
         throws DomEx
     {
         // Check arguments and throw appropriate exceptions
         checkArguments(namespaceURI, qualifiedName);

         name = qualifiedName;
         this.namespaceURI = namespaceURI;
     }

     private void checkArguments(String namespaceURI, String qualifiedName)
         throws DomEx
     {
         // [6] QName ::= (Prefix ':')? LocalPart
         // [7] Prefix ::= NCName
         // [8] LocalPart ::= NCName

 	if (qualifiedName == null) {
             throw new DomEx(DomEx.NAMESPACE_ERR);
         }

 	int first = qualifiedName.indexOf(':');

         if (first <= 0) {
             // no Prefix, only check LocalPart
             if (!XmlNames.isUnqualifiedName(qualifiedName)) {
                 throw new DomEx(DomEx.INVALID_CHARACTER_ERR);
             }
             return;
         }

         // Prefix exists, check everything

 	int last = qualifiedName.lastIndexOf(':');
 	if (last != first) {
             throw new DomEx(DomEx.NAMESPACE_ERR);
         }

         String prefix = qualifiedName.substring(0, first);
         String localName = qualifiedName.substring(first + 1);
 	if (!XmlNames.isUnqualifiedName(prefix)
                 || !XmlNames.isUnqualifiedName(localName)) {
             throw new DomEx(DomEx.INVALID_CHARACTER_ERR);
         }

         // If we get here then we must have a valid prefix
         if (namespaceURI == null || namespaceURI.equals("")
                 || (prefix.equals("xml") &&
                     !namespaceURI.equals(DEFAULT_XML_NS_URI))) {
             throw new DomEx(DomEx.NAMESPACE_ERR);
         }
     }

     public void trimToSize ()
     {
 	super.trimToSize ();
 	if (attributes != null)
 	    attributes.trimToSize ();
     }

     /**
      * Assigns the element's name, when the element has been
      * constructed using the default constructor.  For use by
      * element factories potentially by custom subclasses.
      */
     protected void setTag (String t) { name = t; }

     // Assigns the element's attributes.
     void setAttributes (AttributeSet a)
     {
 	AttributeSet oldAtts = attributes;

 	// Check if the current AttributeSet or any attribute is readonly
 	// isReadonly checks if any of the attributes in the AttributeSet
 	// is readonly..
 	if (oldAtts != null && oldAtts.isReadonly ())
 	    throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);

 	if (a != null)
 	    a.setNameScope (this);
 	attributes = a;
 	if (oldAtts != null)
 	    oldAtts.setNameScope (null);
     }

     // package private -- overrides base class method
     void checkChildType (int type)
     throws DOMException
     {
 	switch (type) {
 	  case ELEMENT_NODE:
 	  case TEXT_NODE:
 	  case COMMENT_NODE:
 	  case PROCESSING_INSTRUCTION_NODE:
 	  case CDATA_SECTION_NODE:
 	  case ENTITY_REFERENCE_NODE:
 	    return;
 	  default:
 	    throw new DomEx (DomEx.HIERARCHY_REQUEST_ERR);
 	}
     }

     // package private -- overrides base class method
     public void setReadonly (boolean deep)
     {
 	if (attributes != null)
 	    attributes.setReadonly ();
 	super.setReadonly (deep);
     }

     public String getNamespace ()
     {
 	String	prefix;
 	String	value;

 	if ((prefix = getPrefix ()) == null)
 	    return getInheritedAttribute ("xmlns");

 	//
 	// XXX return real URLs for these, both here and
 	// in AttributeNode ...
 	//
 	if ("xml".equals (prefix) || "xmlns".equals (prefix))
 	    return null;

 	value = getInheritedAttribute ("xmlns:" + prefix);
 	if (value == null)
 	    throw new IllegalStateException (getMessage ("EN-000",
 					     new Object [] { prefix }));

 	return value;
     }

     /** <b>DOM:</b> Returns the attributes of this element. */
     public NamedNodeMap getAttributes ()
     {
 	if (attributes == null)
 	    attributes = new AttributeSet (this);
         return attributes;
     }

     /**
      * Returns the element and its content as a string, which includes
      * all the markup embedded in this element.  If the element is not
      * fully constructed, the content will not be an XML tag.
      */
     public String toString ()
     {
 	try {
 	    CharArrayWriter	out = new CharArrayWriter ();
 	    XmlWriteContext	x = new XmlWriteContext (out);
 	    writeXml (x);
 	    return out.toString ();
 	} catch (Exception e) {
 	    return super.toString ();
 	}
     }


     /**
      * Writes this element and all of its children out, as well
      * formed XML.
      */
     public void writeXml (XmlWriteContext context) throws IOException
     {
 	Writer	out = context.getWriter ();

 	if (name == null)
 	   throw new IllegalStateException ( getMessage ("EN-002"));

 	out.write (tagStart, 0, 1);	// "<"
 	out.write (name);

         if (attributes != null)
 	    attributes.writeXml (context);

 	//
 	// Write empty nodes as "<EMPTY />" to make sure version 3
 	// and 4 web browsers can read empty tag output as HTML.
 	// XML allows "<EMPTY/>" too, of course.
 	//
 	if (!hasChildNodes ())
 	    out.write (tagEnd, 0, 3);	// " />"
 	else  {
 	    out.write (tagEnd, 2, 1);	// ">"
 	    writeChildrenXml (context);
 	    out.write (tagStart, 0, 2);	// "</"
 	    out.write (name);
 	    out.write (tagEnd, 2, 1);	// ">"
 	}
     }

     /**
      * Assigns the name of the element's ID attribute; only one attribute
      * may have the ID type.  XML supports a kind of validatable internal
      * linking using ID attributes, with IDREF attributes identifying
      * specific nodes (and IDREFS attributes identifying sets of them).
      */
     public void setIdAttributeName (String attName)
     {
 	if (readonly)
 	    throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
 	idAttributeName = attName;
     }

     /**
      * Returns the name of the element's ID attribute, if one is known.
      */
     public String getIdAttributeName ()
 	{ return idAttributeName; }


     public void setUserObject (Object userObject)
 	{ this.userObject = userObject; }

     public Object getUserObject ()
 	{ return userObject; }

     // DOM support

     /** <b>DOM:</b> Returns the ELEMENT_NODE node type. */
     public short getNodeType ()  { return ELEMENT_NODE; }

     /** <b>DOM:</b> Returns the name of the XML tag for this element. */
     public String getTagName () { return name; }

     /** <b>DOM:</b> Returns the name of the XML tag for this element. */
     public String getNodeName () { return name; }

     /** <b>DOM:</b> Returns the value of the named attribute, or an empty
      * string
      */
     public String getAttribute (String name)
     {
 	return (attributes == null)
 	    ? ""
 	    : attributes.getValue (name);
     }

     /**
      * <b>DOM2:</b>
      * @since DOM Level 2
      */
     public String getAttributeNS(String namespaceURI, String localName) {
         //XXX fix this
 	if (attributes == null) {
 	    return "";
         }
 	Attr attr = getAttributeNodeNS(namespaceURI, localName);
 	if (attr == null) {
 	    return "";
         }
 	return attr.getValue();
     }

     /** <b>DOM2:</b> Returns the value of the named attribute, or an empty
      * string
      */
     public boolean hasAttribute (String name)
     {
         if (attributes == null) {
 	    return false;
 	} else if (attributes.getValue (name) != null) {
 	    return true;
 	}
 	return false;
     }

     /**
      * <b>DOM2:</b>
      * @since DOM Level 2
      */
     public boolean hasAttributeNS(String namespaceURI, String localName) {
 	if (attributes == null) {
 	    return false;
         }
 	Attr attr = getAttributeNodeNS(namespaceURI, localName);
 	if (attr == null) {
 	    return false;
         }
 	return true;
     }

     public String getAttribute (String uri, String name)
     {
 	Attr	attr;

 	if (attributes == null)
 	    return "";
 	attr = getAttributeNode (uri, name);
 	if (attr == null)
 	    return "";
 	return attr.getValue ();
     }

     /**
      * <b>DOM2:</b>
      * @since DOM Level 2
      */
     public Attr getAttributeNodeNS(String namespaceURI, String localName) {
 	if (localName == null) {
 	    return null;
         }
 	if (attributes == null) {
             return null;
         }
         for (int i = 0; ; i++) {
             AttributeNode attr = (AttributeNode) attributes.item(i);
             if (attr == null) {
                 return null;
             }
             if (attr.getLocalName().equals(localName)
                 && attr.getNamespaceURI().equals(namespaceURI)) {
                 return attr;
             }
         }
     }

     public Attr getAttributeNode (String uri, String name)
     {
 	if (name == null)
 	    return null;
 	if (attributes != null) {
 	    for (int i = 0; ; i++) {
 		AttributeNode	attr;
 		String		ns;

 		attr = (AttributeNode) attributes.item (i);
 		if (attr == null)
 		    return null;
 		if (!name.equals (attr.getName ()))
 		    continue;
 		ns = attr.getNamespace ();
 		if (ns != null && ns.equals (uri))
 		    return attr;
 	    }
 	}
 	return null;
     }


     /**
      * <b>DOM:</b> Assigns or modifies the value of the specified attribute.
      */
     public void setAttribute (String name, String value)
     throws DOMException
     {
 	AttributeNode	att;

 	if (readonly)
 	    throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
 	if (attributes == null)
 	    attributes = new AttributeSet (this);
 	if ((att = (AttributeNode) attributes.getNamedItem (name)) != null)
 	    att.setNodeValue (value);
 	else {
 	    att = new AttributeNode (name, value, true, null);
 	    att.setOwnerDocument ((XmlDocument) getOwnerDocument ());
 	    att.setOwnerElement(this);
 	    attributes.setNamedItem (att);
 	}
     }

     /**
      * <b>DOM2:</b>
      * @since DOM Level 2
      * XXX Fix err handling and default DEFAULT_XML_NS_URI
      */
     public void setAttributeNS(String namespaceURI, String qualifiedName,
                                String value)
         throws DOMException
     {
         String prefix = XmlNames.getPrefix(qualifiedName);
         if (prefix == null) {
             throw new DomEx(DomEx.NAMESPACE_ERR);
         }

         Attr attr = getAttributeNodeNS(namespaceURI,
                 XmlNames.getLocalPart(qualifiedName));
         if (attr == null) {
             attr = new AttributeNode(namespaceURI, qualifiedName, value,
                                      true, null);
             setAttributeNodeNS(attr);
         } else {
             attr.setValue(value);
             attr.setPrefix(prefix);
         }
     }

     /**
      * <b>DOM2:</b>
      * @since DOM Level 2
      */
     public Attr setAttributeNodeNS(Attr newAttr) throws DOMException {
 	if (readonly) {
 	    throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);
         }
         if (newAttr.getOwnerDocument() != getOwnerDocument()) {
 	    throw new DomEx(DomEx.WRONG_DOCUMENT_ERR);
         }
         Element ownerElement = newAttr.getOwnerElement();
         if (ownerElement != null || ownerElement != this) {
 	    throw new DomEx(DomEx.INUSE_ATTRIBUTE_ERR);
         }

 	if (attributes == null) {
 	    attributes = new AttributeSet(this);
         }

         // Safe to assume we are being passed an AttributeNode
         ((AttributeNode)newAttr).setOwnerElement(this);

 	return (Attr)attributes.setNamedItem(newAttr);
     }

     /** <b>DOM:</b> Remove the named attribute. */
     public void removeAttribute (String name)
     throws DOMException
     {
 	if (readonly)
 	    throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
 	if (attributes == null)
 	    throw new DomEx (DomEx.NOT_FOUND_ERR);
         attributes.removeNamedItem (name);
     }

     /**
      * <b>DOM2:</b>
      * @since DOM Level 2
      */
     public void removeAttributeNS(String namespaceURI, String localName)
         throws DOMException
     {
 	if (readonly) {
 	    throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);
         }
         attributes.removeNamedItemNS(namespaceURI, localName);
     }

     /** <b>DOM:</b>  returns the attribute */
     public Attr getAttributeNode (String name)
     {
 	if (attributes != null)
 	    return (Attr) attributes.getNamedItem (name);
 	else
 	    return null;
     }

     /** <b>DOM:</b> assigns the attribute */
     public Attr setAttributeNode (Attr newAttr)
     throws DOMException
     {
 	if (readonly)
 	    throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
 	if (!(newAttr instanceof AttributeNode))
 	    throw new DomEx (DomEx.WRONG_DOCUMENT_ERR);

 	if (attributes == null)
 	    attributes = new AttributeSet (this);

         ((AttributeNode)newAttr).setOwnerElement(this);
 	return (Attr) attributes.setNamedItem(newAttr);
     }

     /** <b>DOM:</b> removes the attribute with the same name as this one */
     public Attr removeAttributeNode (Attr oldAttr)
     throws DOMException
     {
 	if (isReadonly ())
 	    throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);

 	Attr	attr = getAttributeNode (oldAttr.getNodeName ());
 	if (attr == null)
 	    throw new DomEx (DomEx.NOT_FOUND_ERR);
 	removeAttribute (attr.getNodeName ());
 	return attr;
     }


     /**
      * Creates a new unparented node whose attributes are the same as
      * this node's attributes; if <em>deep</em> is true, the children
      * of this node are cloned as children of the new node.
      */
     public Node cloneNode (boolean deep)
     {
 	try {
 	    ElementNode	retval;

 	    retval = (ElementNode) getOwnerDocument().createElement (name);
 	    if (attributes != null)
 		retval.setAttributes (new AttributeSet (attributes, true));
 	    if (deep) {
 		for (int i = 0; true; i++) {
 		    Node	node = item (i);
 		    if (node == null)
 			break;
 		    retval.appendChild (node.cloneNode (true));
 		}
 	    }
 	    return retval;
 	} catch (DOMException e) {
 	    throw new RuntimeException (getMessage ("EN-001"));
 	}
     }

     /**
      * Convenience method to construct a non-prettyprinting XML write
      * context and call writeXml with it.  Subclasses may choose to
      * to override this method to generate non-XML text,
      *
      * @param out where to emit the XML content of this node
      */
     public void write (Writer out) throws IOException
     {
 	writeXml (new XmlWriteContext (out));
     }
 }
	/*
	* $Id$
	*
	* The Apache Software License, Version 1.1
	*
	*
	* Copyright (c) 2000 The Apache Software Foundation. All rights
	* reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. The end-user documentation included with the redistribution,
	* if any, must include the following acknowledgment:
	* "This product includes software developed by the
	* Apache Software Foundation (http://www.apache.org/)."
	* Alternately, this acknowledgment may appear in the software itself,
	* if and wherever such third-party acknowledgments normally appear.
	*
	* 4. The names "Crimson" and "Apache Software Foundation" must
	* not be used to endorse or promote products derived from this
	* software without prior written permission. For written
	* permission, please contact apache@apache.org.
	*
	* 5. Products derived from this software may not be called "Apache",
	* nor may "Apache" appear in their name, without prior written
	* permission of the Apache Software Foundation.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
	* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	* ====================================================================
	*
	* This software consists of voluntary contributions made by many
	* individuals on behalf of the Apache Software Foundation and was
	* originally based on software copyright (c) 1999, Sun Microsystems, Inc.,
	* http://www.sun.com. For more information on the Apache Software
	* Foundation, please see <http://www.apache.org/>.
	*/

	package org.apache.xerces.tree;

	import java.io.CharArrayWriter;
	import java.io.IOException;
	import java.io.Writer;

	import java.util.Enumeration;

	import org.apache.xerces.tree.XmlNames;

	import org.w3c.dom.*;


	/**
	* This class represents XML elements in a parse tree, and is often
	* subclassed to add custom behaviors. When an XML Document object
	* is built using an <em>XmlDocumentBuilder</em> instance, simple
	* declarative configuration information may be used to control whether
	* this class, or some specialized subclass (e.g. supporting HTML DOM
	* methods) is used for elements in the resulting tree.
	*
	* <P> As well as defining new methods to provide behaviors which are
	* specific to application frameworks, such as Servlets or Swing, such
	* subclasses may also override methods such as <em>doneParse</em>
	* and <em>appendChild</em> to perform some kinds of processing during
	* tree construction. Such processing can include transforming tree
	* structure to better suit the needs of a given application. When
	* such transformation is done, the <em>XmlWritable</em> methods
	* may need to be overridden to make elements transform themselves back
	* to XML without losing information. (One common transformation is
	* eliminating redundant representations of data; attributes of an XML
	* element may correspond to defaultable object properties, and so on.)
	*
	* <P> Element nodes also support a single <em>userObject</em> property,
	* which may be used to bind objects to elements where subclassing is
	* either not possible or is inappropriate. For example, user interface
	* objects often derive from <code>java.awt.Component</code>, so that
	* they can't extend a different class (<em>ElementNode</em>).
	*
	* @see XmlDocumentBuilder
	*
	* @author David Brownell
	* @version $Revision$
	*/
	public class ElementNode extends NamespacedNode implements ElementEx
	{
	private AttributeSet attributes;
	private String idAttributeName;
	private Object userObject;

	private static final char tagStart [] = { '<', '/' };
	private static final char tagEnd [] = { ' ', '/', '>' };
	private static final String
	DEFAULT_XML_NS_URI = "http://www.w3.org/XML/1998/namespace";

	/**
	* Partially constructs an element; its tag will be assigned
	* by the factory (or subclass), while attributes and the
	* parent (and implicitly, siblings) will assigned when it is
	* joined to a DOM document.
	*/
	public ElementNode () { }

	public ElementNode(String namespaceURI, String qualifiedName)
	throws DomEx
	{
	// Check arguments and throw appropriate exceptions
	checkArguments(namespaceURI, qualifiedName);

	name = qualifiedName;
	this.namespaceURI = namespaceURI;
	}

	private void checkArguments(String namespaceURI, String qualifiedName)
	throws DomEx
	{
	// [6] QName ::= (Prefix ':')? LocalPart
	// [7] Prefix ::= NCName
	// [8] LocalPart ::= NCName

	if (qualifiedName == null) {
	throw new DomEx(DomEx.NAMESPACE_ERR);
	}

	int first = qualifiedName.indexOf(':');

	if (first <= 0) {
	// no Prefix, only check LocalPart
	if (!XmlNames.isUnqualifiedName(qualifiedName)) {
	throw new DomEx(DomEx.INVALID_CHARACTER_ERR);
	}
	return;
	}

	// Prefix exists, check everything

	int last = qualifiedName.lastIndexOf(':');
	if (last != first) {
	throw new DomEx(DomEx.NAMESPACE_ERR);
	}

	String prefix = qualifiedName.substring(0, first);
	String localName = qualifiedName.substring(first + 1);
	if (!XmlNames.isUnqualifiedName(prefix)
	\|\| !XmlNames.isUnqualifiedName(localName)) {
	throw new DomEx(DomEx.INVALID_CHARACTER_ERR);
	}

	// If we get here then we must have a valid prefix
	if (namespaceURI == null \|\| namespaceURI.equals("")
	\|\| (prefix.equals("xml") &&
	!namespaceURI.equals(DEFAULT_XML_NS_URI))) {
	throw new DomEx(DomEx.NAMESPACE_ERR);
	}
	}

	public void trimToSize ()
	{
	super.trimToSize ();
	if (attributes != null)
	attributes.trimToSize ();
	}

	/**
	* Assigns the element's name, when the element has been
	* constructed using the default constructor. For use by
	* element factories potentially by custom subclasses.
	*/
	protected void setTag (String t) { name = t; }

	// Assigns the element's attributes.
	void setAttributes (AttributeSet a)
	{
	AttributeSet oldAtts = attributes;

	// Check if the current AttributeSet or any attribute is readonly
	// isReadonly checks if any of the attributes in the AttributeSet
	// is readonly..
	if (oldAtts != null && oldAtts.isReadonly ())
	throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);

	if (a != null)
	a.setNameScope (this);
	attributes = a;
	if (oldAtts != null)
	oldAtts.setNameScope (null);
	}

	// package private -- overrides base class method
	void checkChildType (int type)
	throws DOMException
	{
	switch (type) {
	case ELEMENT_NODE:
	case TEXT_NODE:
	case COMMENT_NODE:
	case PROCESSING_INSTRUCTION_NODE:
	case CDATA_SECTION_NODE:
	case ENTITY_REFERENCE_NODE:
	return;
	default:
	throw new DomEx (DomEx.HIERARCHY_REQUEST_ERR);
	}
	}

	// package private -- overrides base class method
	public void setReadonly (boolean deep)
	{
	if (attributes != null)
	attributes.setReadonly ();
	super.setReadonly (deep);
	}

	public String getNamespace ()
	{
	String prefix;
	String value;

	if ((prefix = getPrefix ()) == null)
	return getInheritedAttribute ("xmlns");

	//
	// XXX return real URLs for these, both here and
	// in AttributeNode ...
	//
	if ("xml".equals (prefix) \|\| "xmlns".equals (prefix))
	return null;

	value = getInheritedAttribute ("xmlns:" + prefix);
	if (value == null)
	throw new IllegalStateException (getMessage ("EN-000",
	new Object [] { prefix }));

	return value;
	}

	/** <b>DOM:</b> Returns the attributes of this element. */
	public NamedNodeMap getAttributes ()
	{
	if (attributes == null)
	attributes = new AttributeSet (this);
	return attributes;
	}

	/**
	* Returns the element and its content as a string, which includes
	* all the markup embedded in this element. If the element is not
	* fully constructed, the content will not be an XML tag.
	*/
	public String toString ()
	{
	try {
	CharArrayWriter out = new CharArrayWriter ();
	XmlWriteContext x = new XmlWriteContext (out);
	writeXml (x);
	return out.toString ();
	} catch (Exception e) {
	return super.toString ();
	}
	}


	/**
	* Writes this element and all of its children out, as well
	* formed XML.
	*/
	public void writeXml (XmlWriteContext context) throws IOException
	{
	Writer out = context.getWriter ();

	if (name == null)
	throw new IllegalStateException ( getMessage ("EN-002"));

	out.write (tagStart, 0, 1); // "<"
	out.write (name);

	if (attributes != null)
	attributes.writeXml (context);

	//
	// Write empty nodes as "<EMPTY />" to make sure version 3
	// and 4 web browsers can read empty tag output as HTML.
	// XML allows "<EMPTY/>" too, of course.
	//
	if (!hasChildNodes ())
	out.write (tagEnd, 0, 3); // " />"
	else {
	out.write (tagEnd, 2, 1); // ">"
	writeChildrenXml (context);
	out.write (tagStart, 0, 2); // "</"
	out.write (name);
	out.write (tagEnd, 2, 1); // ">"
	}
	}

	/**
	* Assigns the name of the element's ID attribute; only one attribute
	* may have the ID type. XML supports a kind of validatable internal
	* linking using ID attributes, with IDREF attributes identifying
	* specific nodes (and IDREFS attributes identifying sets of them).
	*/
	public void setIdAttributeName (String attName)
	{
	if (readonly)
	throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
	idAttributeName = attName;
	}

	/**
	* Returns the name of the element's ID attribute, if one is known.
	*/
	public String getIdAttributeName ()
	{ return idAttributeName; }


	public void setUserObject (Object userObject)
	{ this.userObject = userObject; }

	public Object getUserObject ()
	{ return userObject; }

	// DOM support

	/** <b>DOM:</b> Returns the ELEMENT_NODE node type. */
	public short getNodeType () { return ELEMENT_NODE; }

	/** <b>DOM:</b> Returns the name of the XML tag for this element. */
	public String getTagName () { return name; }

	/** <b>DOM:</b> Returns the name of the XML tag for this element. */
	public String getNodeName () { return name; }

	/** <b>DOM:</b> Returns the value of the named attribute, or an empty
	* string
	*/
	public String getAttribute (String name)
	{
	return (attributes == null)
	? ""
	: attributes.getValue (name);
	}

	/**
	* <b>DOM2:</b>
	* @since DOM Level 2
	*/
	public String getAttributeNS(String namespaceURI, String localName) {
	//XXX fix this
	if (attributes == null) {
	return "";
	}
	Attr attr = getAttributeNodeNS(namespaceURI, localName);
	if (attr == null) {
	return "";
	}
	return attr.getValue();
	}

	/** <b>DOM2:</b> Returns the value of the named attribute, or an empty
	* string
	*/
	public boolean hasAttribute (String name)
	{
	if (attributes == null) {
	return false;
	} else if (attributes.getValue (name) != null) {
	return true;
	}
	return false;
	}

	/**
	* <b>DOM2:</b>
	* @since DOM Level 2
	*/
	public boolean hasAttributeNS(String namespaceURI, String localName) {
	if (attributes == null) {
	return false;
	}
	Attr attr = getAttributeNodeNS(namespaceURI, localName);
	if (attr == null) {
	return false;
	}
	return true;
	}

	public String getAttribute (String uri, String name)
	{
	Attr attr;

	if (attributes == null)
	return "";
	attr = getAttributeNode (uri, name);
	if (attr == null)
	return "";
	return attr.getValue ();
	}

	/**
	* <b>DOM2:</b>
	* @since DOM Level 2
	*/
	public Attr getAttributeNodeNS(String namespaceURI, String localName) {
	if (localName == null) {
	return null;
	}
	if (attributes == null) {
	return null;
	}
	for (int i = 0; ; i++) {
	AttributeNode attr = (AttributeNode) attributes.item(i);
	if (attr == null) {
	return null;
	}
	if (attr.getLocalName().equals(localName)
	&& attr.getNamespaceURI().equals(namespaceURI)) {
	return attr;
	}
	}
	}

	public Attr getAttributeNode (String uri, String name)
	{
	if (name == null)
	return null;
	if (attributes != null) {
	for (int i = 0; ; i++) {
	AttributeNode attr;
	String ns;

	attr = (AttributeNode) attributes.item (i);
	if (attr == null)
	return null;
	if (!name.equals (attr.getName ()))
	continue;
	ns = attr.getNamespace ();
	if (ns != null && ns.equals (uri))
	return attr;
	}
	}
	return null;
	}


	/**
	* <b>DOM:</b> Assigns or modifies the value of the specified attribute.
	*/
	public void setAttribute (String name, String value)
	throws DOMException
	{
	AttributeNode att;

	if (readonly)
	throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
	if (attributes == null)
	attributes = new AttributeSet (this);
	if ((att = (AttributeNode) attributes.getNamedItem (name)) != null)
	att.setNodeValue (value);
	else {
	att = new AttributeNode (name, value, true, null);
	att.setOwnerDocument ((XmlDocument) getOwnerDocument ());
	att.setOwnerElement(this);
	attributes.setNamedItem (att);
	}
	}

	/**
	* <b>DOM2:</b>
	* @since DOM Level 2
	* XXX Fix err handling and default DEFAULT_XML_NS_URI
	*/
	public void setAttributeNS(String namespaceURI, String qualifiedName,
	String value)
	throws DOMException
	{
	String prefix = XmlNames.getPrefix(qualifiedName);
	if (prefix == null) {
	throw new DomEx(DomEx.NAMESPACE_ERR);
	}

	Attr attr = getAttributeNodeNS(namespaceURI,
	XmlNames.getLocalPart(qualifiedName));
	if (attr == null) {
	attr = new AttributeNode(namespaceURI, qualifiedName, value,
	true, null);
	setAttributeNodeNS(attr);
	} else {
	attr.setValue(value);
	attr.setPrefix(prefix);
	}
	}

	/**
	* <b>DOM2:</b>
	* @since DOM Level 2
	*/
	public Attr setAttributeNodeNS(Attr newAttr) throws DOMException {
	if (readonly) {
	throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);
	}
	if (newAttr.getOwnerDocument() != getOwnerDocument()) {
	throw new DomEx(DomEx.WRONG_DOCUMENT_ERR);
	}
	Element ownerElement = newAttr.getOwnerElement();
	if (ownerElement != null \|\| ownerElement != this) {
	throw new DomEx(DomEx.INUSE_ATTRIBUTE_ERR);
	}

	if (attributes == null) {
	attributes = new AttributeSet(this);
	}

	// Safe to assume we are being passed an AttributeNode
	((AttributeNode)newAttr).setOwnerElement(this);

	return (Attr)attributes.setNamedItem(newAttr);
	}

	/** <b>DOM:</b> Remove the named attribute. */
	public void removeAttribute (String name)
	throws DOMException
	{
	if (readonly)
	throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
	if (attributes == null)
	throw new DomEx (DomEx.NOT_FOUND_ERR);
	attributes.removeNamedItem (name);
	}

	/**
	* <b>DOM2:</b>
	* @since DOM Level 2
	*/
	public void removeAttributeNS(String namespaceURI, String localName)
	throws DOMException
	{
	if (readonly) {
	throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);
	}
	attributes.removeNamedItemNS(namespaceURI, localName);
	}

	/** <b>DOM:</b> returns the attribute */
	public Attr getAttributeNode (String name)
	{
	if (attributes != null)
	return (Attr) attributes.getNamedItem (name);
	else
	return null;
	}

	/** <b>DOM:</b> assigns the attribute */
	public Attr setAttributeNode (Attr newAttr)
	throws DOMException
	{
	if (readonly)
	throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);
	if (!(newAttr instanceof AttributeNode))
	throw new DomEx (DomEx.WRONG_DOCUMENT_ERR);

	if (attributes == null)
	attributes = new AttributeSet (this);

	((AttributeNode)newAttr).setOwnerElement(this);
	return (Attr) attributes.setNamedItem(newAttr);
	}

	/** <b>DOM:</b> removes the attribute with the same name as this one */
	public Attr removeAttributeNode (Attr oldAttr)
	throws DOMException
	{
	if (isReadonly ())
	throw new DomEx (DomEx.NO_MODIFICATION_ALLOWED_ERR);

	Attr attr = getAttributeNode (oldAttr.getNodeName ());
	if (attr == null)
	throw new DomEx (DomEx.NOT_FOUND_ERR);
	removeAttribute (attr.getNodeName ());
	return attr;
	}


	/**
	* Creates a new unparented node whose attributes are the same as
	* this node's attributes; if <em>deep</em> is true, the children
	* of this node are cloned as children of the new node.
	*/
	public Node cloneNode (boolean deep)
	{
	try {
	ElementNode retval;

	retval = (ElementNode) getOwnerDocument().createElement (name);
	if (attributes != null)
	retval.setAttributes (new AttributeSet (attributes, true));
	if (deep) {
	for (int i = 0; true; i++) {
	Node node = item (i);
	if (node == null)
	break;
	retval.appendChild (node.cloneNode (true));
	}
	}
	return retval;
	} catch (DOMException e) {
	throw new RuntimeException (getMessage ("EN-001"));
	}
	}

	/**
	* Convenience method to construct a non-prettyprinting XML write
	* context and call writeXml with it. Subclasses may choose to
	* to override this method to generate non-XML text,
	*
	* @param out where to emit the XML content of this node
	*/
	public void write (Writer out) throws IOException
	{
	writeXml (new XmlWriteContext (out));
	}
	}