Commons Math example source code file (ListPopulation.java)

This example Commons Math source code file (ListPopulation.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Math tags/keywords

arraylist, chromosome, illegalargumentexception, illegalargumentexception, iterator, list, list, listpopulation, listpopulation, override, population, population, string, util

The Commons Math ListPopulation.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math.genetics;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Population of chromosomes represented by a {@link List}.
 *
 * @since 2.0
 * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
 */
public abstract class ListPopulation implements Population {

    /** List of chromosomes */
    private List<Chromosome> chromosomes;

    /** maximial size of the population */
    private int populationLimit;


    /**
     * Creates a new ListPopulation instance.
     *
     * @param chromosomes list of chromosomes in the population
     * @param populationLimit maximal size of the population
     */
    public ListPopulation (List<Chromosome> chromosomes, int populationLimit) {
        if (chromosomes.size() > populationLimit) {
            throw new IllegalArgumentException("List of chromosomes bigger than maxPopulationSize.");
        }
        if (populationLimit < 0) {
            throw new IllegalArgumentException("Population limit has to be >= 0");
        }

        this.chromosomes = chromosomes;
        this.populationLimit = populationLimit;
    }

    /**
     * Creates a new ListPopulation instance and initializes its inner
     * chromosome list.
     *
     * @param populationLimit maximal size of the population
     */
    public ListPopulation (int populationLimit) {
        if (populationLimit < 0) {
            throw new IllegalArgumentException("Population limit has to be >= 0");
        }
        this.populationLimit = populationLimit;
        this.chromosomes = new ArrayList<Chromosome>(populationLimit);
    }

    /**
     * Sets the list of chromosomes.
     * @param chromosomes the list of chromosomes
     */
    public void setChromosomes(List<Chromosome> chromosomes) {
        this.chromosomes = chromosomes;
    }

    /**
     * Access the list of chromosomes.
     * @return the list of chromosomes
     */
    public List<Chromosome> getChromosomes() {
        return chromosomes;
    }

    /**
     * Add the given chromosome to the population.
     * @param chromosome the chromosome to add.
     */
    public void addChromosome(Chromosome chromosome) {
        this.chromosomes.add(chromosome);
    }

    /**
     * Access the fittest chromosome in this population.
     * @return the fittest chromosome.
     */
    public Chromosome getFittestChromosome() {
        // best so far
        Chromosome bestChromosome = this.chromosomes.get(0);
        for (Chromosome chromosome : this.chromosomes) {
            if (chromosome.compareTo(bestChromosome) > 0) {
                // better chromosome found
                bestChromosome = chromosome;
            }
        }
        return bestChromosome;
    }

    /**
     * Access the maximum population size.
     * @return the maximum population size.
     */
    public int getPopulationLimit() {
        return this.populationLimit;
    }

    /**
     * Sets the maximal population size.
     * @param populationLimit maximal population size.
     */
    public void setPopulationLimit(int populationLimit) {
        this.populationLimit = populationLimit;
    }

    /**
     * Access the current population size.
     * @return the current population size.
     */
    public int getPopulationSize() {
        return this.chromosomes.size();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        return this.chromosomes.toString();
    }

    /**
     * Chromosome list iterator
     *
     * @return chromosome iterator
     */
    public Iterator<Chromosome> iterator() {
        return chromosomes.iterator();
    }
}