Coverage Report - org.jaxen.function.TranslateFunction

Classes in this File Line Coverage Branch Coverage Complexity
TranslateFunction
96% 
100% 
3.833

 1  
 /*
 2  
  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/TranslateFunction.java,v 1.9 2005/06/28 13:44:45 elharo Exp $
 3  
  * $Revision: 1.9 $
 4  
  * $Date: 2005/06/28 13:44:45 $
 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 1.9 2005/06/28 13:44:45 elharo 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>
 76  
  * <b>4.2</b>
 77  
  * <code><i>string</i> translate(<i>string</i>,<i>string</i>,<i>string</i>)</code>
 78  
  * </p>
 79  
  * 
 80  
  * <blockquote src="http://www.w3.org/TR/xpath#function-translate">
 81  
  * <p>
 82  
  * The <b><a href="http://www.w3.org/TR/xpath#function-translate">translate</a></b> function
 83  
  * returns the first argument string with occurrences of characters in
 84  
  * the second argument string replaced by the character at the
 85  
  * corresponding position in the third argument string. For example,
 86  
  * <code>translate("bar","abc","ABC")</code> returns the string
 87  
  * <code>BAr</code>. If there is a character in the second argument
 88  
  * string with no character at a corresponding position in the third
 89  
  * argument string (because the second argument string is longer than
 90  
  * the third argument string), then occurrences of that character in the
 91  
  * first argument string are removed. For example,
 92  
  * <code>translate("--aaa--","abc-","ABC")</code> returns
 93  
  * <code>"AAA"</code>. If a character occurs more than once in the
 94  
  * second argument string, then the first occurrence determines the
 95  
  * replacement character. If the third argument string is longer than
 96  
  * the second argument string, then excess characters are ignored.
 97  
  * </p>
 98  
  * 
 99  
  * <blockquote> <b>NOTE: </b>The <b>translate</b> function is not a
 100  
  * sufficient solution for case conversion in all languages. A future
 101  
  * version of XPath may provide additional functions for case
 102  
  * conversion.</blockquote>
 103  
  * 
 104  
  * </blockquote>
 105  
  * 
 106  
  * @author Jan Dvorak ( jan.dvorak @ mathan.cz )
 107  
  * 
 108  
  * @see <a href="http://www.w3.org/TR/xpath#function-translate"
 109  
  *      target="_top">Section 4.2 of the XPath Specification</a>
 110  
  */
 111  
 public class TranslateFunction implements Function
 112  
 {
 113  
 
 114  
      /* The translation is done thru a HashMap. Performance tip (for anyone
 115  
       * who needs to improve the performance of this particular function):
 116  
       * Cache the HashMaps, once they are constructed. */
 117  
     
 118  
     /**
 119  
      * Create a new <code>TranslateFunction</code> object.
 120  
      */
 121  294
     public TranslateFunction() {}
 122  
     
 123  
     
 124  
     /** Returns a copy of the first argument in which
 125  
      * characters found in the second argument are replaced by
 126  
      * corresponding characters from the third argument.
 127  
      *
 128  
      * @param context the context at the point in the
 129  
      *         expression when the function is called
 130  
      * @param args a list that contains exactly three items
 131  
      * 
 132  
      * @return a <code>String</code> built from <code>args.get(0)</code> 
 133  
      *     in which occurrences of characters in <code>args.get(1)</code> 
 134  
      *     are replaced by the corresponding characters in <code>args.get(2)</code> 
 135  
      * 
 136  
      * @throws FunctionCallException if <code>args</code> does not have exactly three items
 137  
      */
 138  
     public Object call(Context context,
 139  
                        List args) throws FunctionCallException
 140  
     {
 141  306
         if (args.size() == 3) {
 142  300
             return evaluate( args.get(0),
 143  
                              args.get(1),
 144  
                              args.get(2),
 145  
                              context.getNavigator() );
 146  
         }
 147  
 
 148  6
         throw new FunctionCallException( "translate() requires three arguments." );
 149  
     }
 150  
 
 151  
     /** 
 152  
      * Returns a copy of <code>strArg</code> in which
 153  
      * characters found in <code>fromArg</code> are replaced by
 154  
      * corresponding characters from <code>toArg</code>.
 155  
      * If necessary each argument is first converted to it string-value
 156  
      * as if by the XPath <code>string()</code> function.
 157  
      * 
 158  
      * @param strArg the base string
 159  
      * @param fromArg the characters to be replaced
 160  
      * @param toArg the characters they will be replaced by
 161  
      * @param nav the <code>Navigator</code> used to calculate the string-values of the arguments.
 162  
      * 
 163  
      * @return a copy of <code>strArg</code> in which
 164  
      *  characters found in <code>fromArg</code> are replaced by
 165  
      *  corresponding characters from <code>toArg</code>
 166  
      *  
 167  
      * @throws FunctionCallException if one of the arguments is a malformed Unicode string;
 168  
      *     that is, if surrogate characters don't line up properly
 169  
      * 
 170  
      */
 171  
     public static String evaluate(Object strArg,
 172  
                                   Object fromArg,
 173  
                                   Object toArg,
 174  
                                   Navigator nav) throws FunctionCallException
 175  
     {
 176  300
         String inStr = StringFunction.evaluate( strArg, nav );
 177  300
         String fromStr = StringFunction.evaluate( fromArg, nav );
 178  300
         String toStr = StringFunction.evaluate( toArg, nav );
 179  
     
 180  
         // Initialize the mapping in a HashMap
 181  300
         Map characterMap = new HashMap();
 182  300
         String[] fromCharacters = toUnicodeCharacters(fromStr);
 183  300
         String[] toCharacters = toUnicodeCharacters(toStr);
 184  288
         int fromLen = fromCharacters.length;
 185  288
         int toLen = toCharacters.length;
 186  1128
         for ( int i = 0; i < fromLen; i++ ) {
 187  840
             String cFrom = fromCharacters[i];
 188  840
             if ( characterMap.containsKey( cFrom ) ) {
 189  
                 // We've seen the character before, ignore
 190  24
                 continue;
 191  
             }
 192  
             
 193  816
             if ( i < toLen ) {
 194  
                 // Will change
 195  672
                 characterMap.put( cFrom, toCharacters[i] );
 196  
             } 
 197  
             else {
 198  
                 // Will delete
 199  144
                 characterMap.put( cFrom, null );
 200  
             }
 201  
         }
 202  
 
 203  
         // Process the input string thru the map
 204  288
         StringBuffer outStr = new StringBuffer( inStr.length() );
 205  288
         String[] inCharacters = toUnicodeCharacters(inStr);
 206  288
         int inLen = inCharacters.length;
 207  1314
         for ( int i = 0; i < inLen; i++ ) {
 208  1026
             String cIn = inCharacters[i];
 209  1026
             if ( characterMap.containsKey( cIn ) ) {
 210  822
                 String cTo = (String) characterMap.get( cIn );
 211  822
                 if ( cTo != null ) {
 212  678
                     outStr.append( cTo );
 213  
                 }
 214  
             } 
 215  
             else {
 216  204
                 outStr.append( cIn );
 217  
             }
 218  
         }
 219  
     
 220  288
         return outStr.toString();
 221  
     }
 222  
 
 223  
     private static String[] toUnicodeCharacters(String s) throws FunctionCallException {
 224  
 
 225  888
         String[] result = new String[s.length()];
 226  888
         int stringLength = 0;
 227  3540
         for (int i = 0; i < s.length(); i++) {
 228  2664
             char c1 = s.charAt(i);
 229  2664
             if (isHighSurrogate(c1)) {
 230  
                 try {
 231  54
                     char c2 = s.charAt(i+1);
 232  54
                     if (isLowSurrogate(c2)) {
 233  42
                         result[stringLength] = (c1 + "" + c2).intern();
 234  42
                         i++;
 235  
                     }
 236  
                     else {
 237  12
                         throw new FunctionCallException("Mismatched surrogate pair in translate function");
 238  
                     }
 239  
                 }
 240  0
                 catch (StringIndexOutOfBoundsException ex) {
 241  0
                     throw new FunctionCallException("High surrogate without low surrogate at end of string passed to translate function");
 242  42
                 }
 243  
             }
 244  
             else {
 245  2610
                 result[stringLength]=String.valueOf(c1).intern();
 246  
             }
 247  2652
             stringLength++;
 248  
         }
 249  
         
 250  876
         if (stringLength == result.length) return result;
 251  
         
 252  
         // trim array
 253  42
         String[] trimmed = new String[stringLength];
 254  42
         System.arraycopy(result, 0, trimmed, 0, stringLength);
 255  42
         return trimmed;
 256  
         
 257  
     }
 258  
 
 259  
     private static boolean isHighSurrogate(char c) {
 260  2664
         return c >= 0xD800 && c <= 0xDBFF;
 261  
     }
 262  
      
 263  
     private static boolean isLowSurrogate(char c) {
 264  54
         return c >= 0xDC00 && c <= 0xDFFF;
 265  
     }
 266  
      
 267  
 }