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

/* TranslateFunction.java -- 
   Copyright (C) 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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exception statement from your version. */

package gnu.xml.xpath;

import java.util.List;
import javax.xml.namespace.QName;
import org.w3c.dom.Node;

/**
 * The <code>translate</code> function returns the first argument string
 * with occurrences of characters in the second argument string replaced by
 * the character at the corresponding position in the third argument string.
 * For example, translate("bar","abc","ABC") returns the string BAr. If
 * there is a character in the second argument string with no character at a
 * corresponding position in the third argument string (because the second
 * argument string is longer than the third argument string), then
 * occurrences of that character in the first argument string are removed.
 * For example, translate("--aaa--","abc-","ABC") returns "AAA". If a
 * character occurs more than once in the second argument string, then the
 * first occurrence determines the replacement character. If the third
 * argument string is longer than the second argument string, then excess
 * characters are ignored.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
final class TranslateFunction
  extends Expr
{

  final Expr arg1;
  final Expr arg2;
  final Expr arg3;

  TranslateFunction(List args)
  {
    this((Expr) args.get(0), (Expr) args.get(1), (Expr) args.get(2));
  }

  TranslateFunction(Expr arg1, Expr arg2, Expr arg3)
  {
    this.arg1 = arg1;
    this.arg2 = arg2;
    this.arg3 = arg3;
  }

  public Object evaluate(Node context, int pos, int len)
  {
    Object val1 = arg1.evaluate(context, pos, len);
    Object val2 = arg2.evaluate(context, pos, len);
    Object val3 = arg3.evaluate(context, pos, len);
    String string = _string(context, val1);
    String search = _string(context, val2);
    String replace = _string(context, val3);
    StringBuffer buf = new StringBuffer();
    int l1 = string.length();
    int l2 = search.length();
    int l3 = replace.length();
    for (int i = 0; i < l1; i++)
      {
        char c = string.charAt(i);
        boolean replaced = false;
        for (int j = 0; j < l2; j++)
          {
            if (c == search.charAt(j))
              {
                if (j < l3)
                  {
                    buf.append(replace.charAt(j));
                  }
                replaced = true;
              }
          }
        if (!replaced)
          {
            buf.append(c);
          } 
      } 
    return new String(buf);
  }

  public Expr clone(Object context)
  {
    return new TranslateFunction(arg1.clone(context), arg2.clone(context),
                                 arg3.clone(context));
  }

  public boolean references(QName var)
  {
    return (arg1.references(var) || arg2.references(var) ||
            arg3.references(var));
  }
  
  public String toString()
  {
    return "translate(" + arg1 + "," + arg2 + "," + arg3 + ")";
  }
  
}