/*

     dsh-evolve  Framework for evolutionary algorithms.

     Copyright (c) 2005-2013 held jointly by the individual authors.

     This library is free software; you can redistribute it and/or modify it

     under the terms of the GNU Lesser General Public License as published

     by the Free Software Foundation; either version 3 of the License, or (at

     your option) any later version.

     This library is distributed in the hope that it will be useful, but WITHOUT

     ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY or

     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public

     License for more details.

     You should have received a copy of the GNU Lesser General Public License

     along with this library;  if not, write to the Free Software Foundation,

     Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA.

     > http://www.fsf.org/licensing/licenses/lgpl.html

     > http://www.opensource.org/licenses/lgpl-license.php

 */

 package org.dishevelled.evolve.fitness;

 import java.util.ArrayList;

 import java.util.List;

 import org.dishevelled.evolve.Fitness;

 import org.dishevelled.functor.BinaryFunction;

 //import cern.colt...functions.DoubleDoubleFunction;

 /**

  * Composite fitness function.

  *

  * @param <I> individual type

  * @author  Michael Heuer

  * @version $Revision$ $Date$

  */

 public final class CompositeFitness<I>

     implements Fitness<I>

 {

     /** List of child fitness functions. */

     private final List<Fitness<? super I>> children;

     /** Aggregate function. */

     private final BinaryFunction<Double, Double, Double> aggregate;

     //private final DoubleDoubleFunction aggregate;

     /**

      * Create a new composite fitness function with the specified list

      * of child fitness functions and the specified aggregate function.

      *

      * @param children list of child fitness functions, must not be

      *    null and must contain at least one fitness function

      * @param aggregate aggregate function, must not be null

      */

     public CompositeFitness(final List<Fitness<? super I>> children,

                                final BinaryFunction<Double, Double, Double> aggregate)

     //                               final DoubleDoubleFunction aggregate)

     {

         if (children == null)

         {

             throw new IllegalArgumentException("children must not be null");

         }

         if (children.isEmpty())

         {

             throw new IllegalArgumentException("children must contain at least one fitness function");

         }

         if (aggregate == null)

         {

             throw new IllegalArgumentException("aggregate must not be null");

         }

         this.children = new ArrayList<Fitness<? super I>>(children);

         this.aggregate = aggregate;

     }

     /** {@inheritDoc} */

     public Double score(final I individual)

     {

         int last = children.size() - 1;

         double rv = children.get(last).score(individual);

         for (int i = last; --i >= 0;)

         {

             rv = aggregate.evaluate(rv, children.get(i).score(individual));

         }

         return rv;

     }

 }