src/org/apache/xpath/functions/FuncUniqueID.java

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2003 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 "Xalan" 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,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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 * 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, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xpath.functions;

import org.apache.xpath.res.XPATHErrorResources;

//import org.w3c.dom.Node;
//import org.w3c.dom.traversal.NodeIterator;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMIterator;

import java.util.Vector;

import org.apache.xpath.XPathContext;
import org.apache.xpath.XPath;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.objects.XString;
import org.apache.xpath.objects.XSequence;
import org.apache.xpath.objects.XJavaObject;
import org.apache.xml.utils.QName;
import org.apache.xml.dtm.XType;

/**
 * <meta name="usage" content="advanced"/>
 * Execute the xf:node-name function, returning a QName.
 */
public class FuncUniqueID extends FunctionDef1Arg
{
  /**
   * Execute the xf:unique-ID() function.  The function must return
   * a valid object.
   * @param xctxt The current execution context.
   * @return An XString containing the value of the ID-typed attribute of
   * this element, or 
   * XObject.EMPTY if the input wasn't an Element with an ID.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
  {
    int contextHandle = getArg0AsNode(xctxt);
    
    if(DTM.NULL != contextHandle)
    {
	    DTM dtm = xctxt.getDTM(contextHandle);
    	if(dtm.getNodeType(contextHandle) == DTM.ELEMENT_NODE)
	    {
			for(int attrHandle=dtm.getFirstAttribute(contextHandle);
				attrHandle!=DTM.NULL;
				attrHandle=dtm.getNextAttribute(attrHandle))
			{
				if("ID".equals(dtm.getSchemaTypeLocalName(attrHandle))
					&& XType.XMLSCHEMA_NAMESPACE.equals(dtm.getSchemaTypeNamespace(attrHandle)))
					return new XString(dtm.getNodeValue(attrHandle));
				
			}
	    }
    }

	return XSequence.EMPTY;
  }
}