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: FuncLang.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.XBoolean;
026    import org.apache.xpath.objects.XObject;
027    
028    /**
029     * Execute the Lang() function.
030     * @xsl.usage advanced
031     */
032    public class FuncLang extends FunctionOneArg
033    {
034        static final long serialVersionUID = -7868705139354872185L;
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        String lang = m_arg0.execute(xctxt).str();
048        int parent = xctxt.getCurrentNode();
049        boolean isLang = false;
050        DTM dtm = xctxt.getDTM(parent);
051    
052        while (DTM.NULL != parent)
053        {
054          if (DTM.ELEMENT_NODE == dtm.getNodeType(parent))
055          {
056            int langAttr = dtm.getAttributeNode(parent, "http://www.w3.org/XML/1998/namespace", "lang");
057    
058            if (DTM.NULL != langAttr)
059            {
060              String langVal = dtm.getNodeValue(langAttr);
061              // %OPT%
062              if (langVal.toLowerCase().startsWith(lang.toLowerCase()))
063              {
064                int valLen = lang.length();
065    
066                if ((langVal.length() == valLen)
067                        || (langVal.charAt(valLen) == '-'))
068                {
069                  isLang = true;
070                }
071              }
072    
073              break;
074            }
075          }
076    
077          parent = dtm.getParent(parent);
078        }
079    
080        return isLang ? XBoolean.S_TRUE : XBoolean.S_FALSE;
081      }
082    }