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: FuncTranslate.java 468655 2006-10-28 07:12:06Z minchau $
020     */
021    package org.apache.xpath.functions;
022    
023    import org.apache.xpath.XPathContext;
024    import org.apache.xpath.objects.XObject;
025    import org.apache.xpath.objects.XString;
026    
027    /**
028     * Execute the Translate() function.
029     * @xsl.usage advanced
030     */
031    public class FuncTranslate extends Function3Args
032    {
033        static final long serialVersionUID = -1672834340026116482L;
034    
035      /**
036       * Execute the function.  The function must return
037       * a valid object.
038       * @param xctxt The current execution context.
039       * @return A valid XObject.
040       *
041       * @throws javax.xml.transform.TransformerException
042       */
043      public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
044      {
045    
046        String theFirstString = m_arg0.execute(xctxt).str();
047        String theSecondString = m_arg1.execute(xctxt).str();
048        String theThirdString = m_arg2.execute(xctxt).str();
049        int theFirstStringLength = theFirstString.length();
050        int theThirdStringLength = theThirdString.length();
051    
052        // A vector to contain the new characters.  We'll use it to construct
053        // the result string.
054        StringBuffer sbuffer = new StringBuffer();
055    
056        for (int i = 0; i < theFirstStringLength; i++)
057        {
058          char theCurrentChar = theFirstString.charAt(i);
059          int theIndex = theSecondString.indexOf(theCurrentChar);
060    
061          if (theIndex < 0)
062          {
063    
064            // Didn't find the character in the second string, so it
065            // is not translated.
066            sbuffer.append(theCurrentChar);
067          }
068          else if (theIndex < theThirdStringLength)
069          {
070    
071            // OK, there's a corresponding character in the
072            // third string, so do the translation...
073            sbuffer.append(theThirdString.charAt(theIndex));
074          }
075          else
076          {
077    
078            // There's no corresponding character in the
079            // third string, since it's shorter than the
080            // second string.  In this case, the character
081            // is removed from the output string, so don't
082            // do anything.
083          }
084        }
085    
086        return new XString(sbuffer.toString());
087      }
088    }