001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements. See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership. The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the  "License");
007     * you may not use this file except in compliance with the License.
008     * You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    /*
019     * $Id: FuncGenerateId.java 468655 2006-10-28 07:12:06Z minchau $
020     */
021    package org.apache.xpath.functions;
022    
023    import org.apache.xml.dtm.DTM;
024    import org.apache.xpath.XPathContext;
025    import org.apache.xpath.objects.XObject;
026    import org.apache.xpath.objects.XString;
027    
028    /**
029     * Execute the GenerateId() function.
030     * @xsl.usage advanced
031     */
032    public class FuncGenerateId extends FunctionDef1Arg
033    {
034        static final long serialVersionUID = 973544842091724273L;
035    
036      /**
037       * Execute the function.  The function must return
038       * a valid object.
039       * @param xctxt The current execution context.
040       * @return A valid XObject.
041       *
042       * @throws javax.xml.transform.TransformerException
043       */
044      public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
045      {
046    
047        int which = getArg0AsNode(xctxt);
048    
049        if (DTM.NULL != which)
050        {
051          // Note that this is a different value than in previous releases
052          // of Xalan. It's sensitive to the exact encoding of the node
053          // handle anyway, so fighting to maintain backward compatability
054          // really didn't make sense; it may change again as we continue
055          // to experiment with balancing document and node numbers within
056          // that value.
057          return new XString("N" + Integer.toHexString(which).toUpperCase());
058        }
059        else
060          return XString.EMPTYSTRING;
061      }
062    }