libjava/classpath/gnu/xml/xpath/TranslateFunction.java

   1 /* TranslateFunction.java --
   2    Copyright (C) 2004 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package gnu.xml.xpath;
  39
  40 import gnu.java.lang.CPStringBuilder;
  41
  42 import java.util.List;
  43 import javax.xml.namespace.QName;
  44 import org.w3c.dom.Node;
  45
  46 /**
  47  * The <code>translate</code> function returns the first argument string
  48  * with occurrences of characters in the second argument string replaced by
  49  * the character at the corresponding position in the third argument string.
  50  * For example, translate("bar","abc","ABC") returns the string BAr. If
  51  * there is a character in the second argument string with no character at a
  52  * corresponding position in the third argument string (because the second
  53  * argument string is longer than the third argument string), then
  54  * occurrences of that character in the first argument string are removed.
  55  * For example, translate("--aaa--","abc-","ABC") returns "AAA". If a
  56  * character occurs more than once in the second argument string, then the
  57  * first occurrence determines the replacement character. If the third
  58  * argument string is longer than the second argument string, then excess
  59  * characters are ignored.
  60  *
  61  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  62  */
  63 final class TranslateFunction
  64   extends Expr
  65 {
  66
  67   final Expr arg1;
  68   final Expr arg2;
  69   final Expr arg3;
  70
  71   TranslateFunction(List<Expr> args)
  72   {
  73     this(args.get(0), args.get(1), args.get(2));
  74   }
  75
  76   TranslateFunction(Expr arg1, Expr arg2, Expr arg3)
  77   {
  78     this.arg1 = arg1;
  79     this.arg2 = arg2;
  80     this.arg3 = arg3;
  81   }
  82
  83   public Object evaluate(Node context, int pos, int len)
  84   {
  85     Object val1 = arg1.evaluate(context, pos, len);
  86     Object val2 = arg2.evaluate(context, pos, len);
  87     Object val3 = arg3.evaluate(context, pos, len);
  88     String string = _string(context, val1);
  89     String search = _string(context, val2);
  90     String replace = _string(context, val3);
  91     CPStringBuilder buf = new CPStringBuilder();
  92     int l1 = string.length();
  93     int l2 = search.length();
  94     int l3 = replace.length();
  95     for (int i = 0; i < l1; i++)
  96       {
  97         char c = string.charAt(i);
  98         boolean replaced = false;
  99         for (int j = 0; j < l2; j++)
 100           {
 101             if (c == search.charAt(j))
 102               {
 103                 if (j < l3)
 104                   {
 105                     buf.append(replace.charAt(j));
 106                   }
 107                 replaced = true;
 108               }
 109           }
 110         if (!replaced)
 111           {
 112             buf.append(c);
 113           }
 114       }
 115     return buf.toString();
 116   }
 117
 118   public Expr clone(Object context)
 119   {
 120     return new TranslateFunction(arg1.clone(context), arg2.clone(context),
 121                                  arg3.clone(context));
 122   }
 123
 124   public boolean references(QName var)
 125   {
 126     return (arg1.references(var) || arg2.references(var) ||
 127             arg3.references(var));
 128   }
 129
 130   public String toString()
 131   {
 132     return "translate(" + arg1 + "," + arg2 + "," + arg3 + ")";
 133   }
 134
 135 }