// AID-GENERATED
// =========================================================================
// This class was generated by AID - Abstract Interface Definition          
// DO NOT MODIFY, but use the org.freehep.aid.Aid utility to regenerate it. 
// =========================================================================

//  This file is part of the AIDA library
//  Copyright (C) 2002 by the AIDA team.  All rights reserved.
//  This library is free software and under the terms of the
//  GNU Library General Public License described in the LGPL.txt 
package hep.aida;


/**
 * User's level interface of an IEvaluator.
 *
 * @author The AIDA team (http://aida.freehep.org/)
 *
 */
 
public interface IEvaluator {

  /**
   * Initialize the IEvaluator and associate it to an ITuple.
   * @param ituple The ITuple to which the IEvaluator is associated.
   * @throws       IllegalArgumentException If the IEvaluator and 
   *               the ITuple are not compatible.
   *
   */ 
    public void initialize(ITuple ituple) throws IllegalArgumentException;

  /**
   * Evaluate the IEvaluator from the data in the 
   * current row of the ITuple it is associated to.
   * @return The current value of the Evaluator.
   * @throws RuntimeException if the IEvaluator has not been initialized.
   *
   */ 
    public double evaluateDouble() throws RuntimeException;

   /**
    * Get the expression that defined the IEvaluator.
    * @return The expression.
    *
    */
    public String expression();
} // class or interface