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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/TranslateFunction.java,v 1.4 2003/06/29 18:04:41 ssanders Exp $
3    * $Revision: 1.4 $
4    * $Date: 2003/06/29 18:04:41 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions
13   * are met:
14   * 
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows 
20   *    these conditions in the documentation and/or other materials 
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   * 
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   * 
31   * In addition, we request (but do not require) that you include in the 
32   * end-user documentation provided with the redistribution and/or in the 
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos 
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many 
54   * individuals on behalf of the Jaxen Project and was originally 
55   * created by bob mcwhirter <bob@werken.com> and 
56   * James Strachan <jstrachan@apache.org>.  For more information on the 
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   * 
59   * $Id: TranslateFunction.java,v 1.4 2003/06/29 18:04:41 ssanders Exp $
60   */
61  
62  
63  package org.jaxen.function;
64  
65  import java.util.HashMap;
66  import java.util.List;
67  import java.util.Map;
68  
69  import org.jaxen.Context;
70  import org.jaxen.Function;
71  import org.jaxen.FunctionCallException;
72  import org.jaxen.Navigator;
73  
74  /***
75   * <p><b>4.2</b> <code><i>string</i> translate(<i>string</i>,<i>string</i>,<i>string</i>)</code> 
76   * 
77   * The translation is done thru a HashMap.
78   * Performance tip (for anyone who needs to improve the performance of this particular function):
79   *   Cache the HashMaps, once they are constructed.
80   * 
81   * @author Jan Dvorak ( jan.dvorak @ mathan.cz )
82   * 
83   */
84  public class TranslateFunction implements Function
85  {
86  
87      public Object call(Context context,
88                         List args) throws FunctionCallException
89      {
90      if (args.size() == 3)
91          {
92              return evaluate( args.get(0),
93                               args.get(1),
94                               args.get(2),
95                               context.getNavigator() );
96          }
97  
98          throw new FunctionCallException( "translate() requires three arguments." );
99      }
100 
101     public static String evaluate(Object strArg,
102                                   Object fromArg,
103                                   Object toArg,
104                                   Navigator nav)
105     {
106         String inStr = StringFunction.evaluate( strArg, nav );
107         String fromStr = StringFunction.evaluate( fromArg, nav );
108         String toStr = StringFunction.evaluate( toArg, nav );
109     
110     // Initialize the mapping in a HashMap
111     Map charMap = new HashMap();
112     int fromLen = fromStr.length();
113     int toLen = toStr.length();
114     for ( int i = 0; i < fromLen; ++i ) {
115         String cFrom = fromStr.substring( i, i+1 ).intern();
116         if ( charMap.containsKey( cFrom ) ) {
117         // We've seen the character before, ignore
118         continue;
119         }
120         if ( i < toLen ) {
121         Character cTo = new Character( toStr.charAt( i ) );
122         // Will change
123         charMap.put( cFrom, cTo );
124         } else {
125         // Will delete
126         charMap.put( cFrom, null );
127         }
128     }
129 
130     // Process the input string thru the map
131     StringBuffer outStr = new StringBuffer( inStr.length() );
132     int inLen = inStr.length();
133     for ( int i = 0; i < inLen; ++i ) {
134         String cIn = inStr.substring( i, i+1 );
135         if ( charMap.containsKey( cIn ) ) {
136         Character cTo = (Character) charMap.get( cIn );
137         if ( cTo != null ) {
138             outStr.append( cTo.charValue() );
139         }
140         } else {
141         outStr.append( cIn );
142         }
143     }
144 
145     return new String( outStr );
146     }
147 }
148