001    /*
002     * Copyright 2011 Christian Kumpe http://kumpe.de/christian/java
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *     http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package de.kumpe.hadooptimizer.impl;
017    
018    import java.util.Collection;
019    
020    import de.kumpe.hadooptimizer.PopulationWriter;
021    
022    /**
023     * A {@link PopulationWriter} which stores the given population in memory.
024     * 
025     * @param <I>
026     *            the individuals' type
027     * 
028     * @author <a href="http://kumpe.de/christian/java">Christian Kumpe</a>
029     */
030    public class MemoryPopulationWriter<I> implements PopulationWriter<I> {
031            private static final long serialVersionUID = 1L;
032    
033            private Collection<I> population = null;
034    
035            @Override
036            public void write(final Collection<I> population) {
037                    this.population = population;
038            }
039    
040            public Collection<I> getPopulation() {
041                    return population;
042            }
043    
044            public I getWinner() {
045                    if (null == population) {
046                            return null;
047                    }
048                    return population.iterator().next();
049            }
050    }