/* StartsWithFunction.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.

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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 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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combination.

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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package gnu.xml.xpath;

import java.util.List;
import org.w3c.dom.Node;

/**
 * The <code>starts-with</code> function returns true if the first argument
 * string starts with the second argument string, and otherwise returns false.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
final class StartsWithFunction
  extends Expr
{

  final Expr arg1;
  final Expr arg2;

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

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

  public Object evaluate(Node context, int pos, int len)
  {
    Object val1 = arg1.evaluate(context, pos, len);
    Object val2 = arg2.evaluate(context, pos, len);
    String s1 = _string(context, val1);
    String s2 = _string(context, val2);
    return s1.startsWith(s2) ? Boolean.TRUE : Boolean.FALSE;
  }

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

  public String toString()
  {
    return "starts-with(" + arg1 + "," + arg2 + ")";
  }
  
}