/*

     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.select;

 import java.util.Collection;

 import org.dishevelled.weighted.WeightedMap;

 import org.dishevelled.evolve.Selection;

 /**

  * Null selection function.

  *

  * @param <I> individual type

  * @author  Michael Heuer

  */

 public final class NullSelection<I>

     implements Selection<I>

 {

     /** {@inheritDoc} */

     public Collection<I> select(final Collection<I> population,

                                 final WeightedMap<I> scores)

     {

         if (scores.totalWeight() == 0.0d)

         {

             throw new IllegalStateException("scores total weight must be greater than zero");

         }

         return population;

     }

 }