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: FuncNamespace.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 Namespace() function.
030     * @xsl.usage advanced
031     */
032    public class FuncNamespace extends FunctionDef1Arg
033    {
034        static final long serialVersionUID = -4695674566722321237L;
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 context = getArg0AsNode(xctxt);
048        
049        String s;
050        if(context != DTM.NULL)
051        {
052          DTM dtm = xctxt.getDTM(context);
053          int t = dtm.getNodeType(context);
054          if(t == DTM.ELEMENT_NODE)
055          {
056            s = dtm.getNamespaceURI(context);
057          }
058          else if(t == DTM.ATTRIBUTE_NODE)
059          {
060    
061            // This function always returns an empty string for namespace nodes.
062            // We check for those here.  Fix inspired by Davanum Srinivas.
063    
064            s = dtm.getNodeName(context);
065            if(s.startsWith("xmlns:") || s.equals("xmlns"))
066              return XString.EMPTYSTRING;
067    
068            s = dtm.getNamespaceURI(context);
069          }
070          else
071            return XString.EMPTYSTRING;
072        }
073        else 
074          return XString.EMPTYSTRING;
075        
076        return ((null == s) ? XString.EMPTYSTRING : new XString(s));
077      }
078    }