code: //==============================================================================
  //	
  //	Copyright (c) 2002-
  //	Authors:
  //	* Dave Parker <david.parker@comlab.ox.ac.uk> (University of Oxford)
  //	
  //------------------------------------------------------------------------------
  //	
  //	This file is part of PRISM.
  //	
  //	PRISM 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 of the License, or
  //	(at your option) any later version.
  //	
  //	PRISM 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 PRISM; if not, write to the Free Software Foundation,
  //	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  //	
  //==============================================================================
  
  package prism;
  
  import java.util.Map.Entry;
  
  /**
   * Simple class to store a pair of values.
   */
  public class Pair<X,Y> implements Entry<X, Y>
  {
  	public X first;
  	public Y second;
  	
  	public Pair(X first, Y second)
  	{
  		this.first = first;
  		this.second = second;
  	}
  
  	@Override
  	public X getKey() {
  		return first;
  	}
  
  	@Override
  	public Y getValue() {
  		return second;
  	}
  
  	@Override
  	public Y setValue(Y value) {
  		second = value;
  		return second;
  	}
  	
  	@Override
  	public String toString()
  	{
  		return "(" + first + "," + second + ")"; 
  	}
  }
  