Java tutorial
/* * 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.math3.genetics; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.Iterator; import java.util.List; import org.apache.commons.math3.exception.util.LocalizedFormats; import org.apache.commons.math3.exception.NotPositiveException; import org.apache.commons.math3.exception.NullArgumentException; import org.apache.commons.math3.exception.NumberIsTooLargeException; import org.apache.commons.math3.exception.NumberIsTooSmallException; /** * Population of chromosomes represented by a {@link List}. * * @since 2.0 * @version $Id: ListPopulation.java 1422195 2012-12-15 06:45:18Z psteitz $ */ public abstract class ListPopulation implements Population { /** List of chromosomes */ private List<Chromosome> chromosomes; /** maximal size of the population */ private int populationLimit; /** * Creates a new ListPopulation instance and initializes its inner chromosome list. * * @param populationLimit maximal size of the population * @throws NotPositiveException if the population limit is not a positive number (< 1) */ public ListPopulation(final int populationLimit) throws NotPositiveException { this(Collections.<Chromosome>emptyList(), populationLimit); } /** * Creates a new ListPopulation instance. * <p> * Note: the chromosomes of the specified list are added to the population. * * @param chromosomes list of chromosomes to be added to the population * @param populationLimit maximal size of the population * @throws NullArgumentException if the list of chromosomes is {@code null} * @throws NotPositiveException if the population limit is not a positive number (< 1) * @throws NumberIsTooLargeException if the list of chromosomes exceeds the population limit */ public ListPopulation(final List<Chromosome> chromosomes, final int populationLimit) throws NullArgumentException, NotPositiveException, NumberIsTooLargeException { if (chromosomes == null) { throw new NullArgumentException(); } if (populationLimit <= 0) { throw new NotPositiveException(LocalizedFormats.POPULATION_LIMIT_NOT_POSITIVE, populationLimit); } if (chromosomes.size() > populationLimit) { throw new NumberIsTooLargeException(LocalizedFormats.LIST_OF_CHROMOSOMES_BIGGER_THAN_POPULATION_SIZE, chromosomes.size(), populationLimit, false); } this.populationLimit = populationLimit; this.chromosomes = new ArrayList<Chromosome>(populationLimit); this.chromosomes.addAll(chromosomes); } /** * Sets the list of chromosomes. * <p> * Note: this method removed all existing chromosomes in the population and adds all chromosomes * of the specified list to the population. * * @param chromosomes the list of chromosomes * @throws NullArgumentException if the list of chromosomes is {@code null} * @throws NumberIsTooLargeException if the list of chromosomes exceeds the population limit * @deprecated use {@link #addChromosomes(Collection)} instead */ @Deprecated public void setChromosomes(final List<Chromosome> chromosomes) throws NullArgumentException, NumberIsTooLargeException { if (chromosomes == null) { throw new NullArgumentException(); } if (chromosomes.size() > populationLimit) { throw new NumberIsTooLargeException(LocalizedFormats.LIST_OF_CHROMOSOMES_BIGGER_THAN_POPULATION_SIZE, chromosomes.size(), populationLimit, false); } this.chromosomes.clear(); this.chromosomes.addAll(chromosomes); } /** * Add a {@link Collection} of chromosomes to this {@link Population}. * @param chromosomeColl a {@link Collection} of chromosomes * @throws NumberIsTooLargeException if the population would exceed the population limit when * adding this chromosome * @since 3.1 */ public void addChromosomes(final Collection<Chromosome> chromosomeColl) throws NumberIsTooLargeException { if (chromosomes.size() + chromosomeColl.size() > populationLimit) { throw new NumberIsTooLargeException(LocalizedFormats.LIST_OF_CHROMOSOMES_BIGGER_THAN_POPULATION_SIZE, chromosomes.size(), populationLimit, false); } this.chromosomes.addAll(chromosomeColl); } /** * Returns an unmodifiable list of the chromosomes in this population. * @return the unmodifiable list of chromosomes */ public List<Chromosome> getChromosomes() { return Collections.unmodifiableList(chromosomes); } /** * Access the list of chromosomes. * @return the list of chromosomes * @since 3.1 */ protected List<Chromosome> getChromosomeList() { return chromosomes; } /** * Add the given chromosome to the population. * * @param chromosome the chromosome to add. * @throws NumberIsTooLargeException if the population would exceed the {@code populationLimit} after * adding this chromosome */ public void addChromosome(final Chromosome chromosome) throws NumberIsTooLargeException { if (chromosomes.size() >= populationLimit) { throw new NumberIsTooLargeException(LocalizedFormats.LIST_OF_CHROMOSOMES_BIGGER_THAN_POPULATION_SIZE, chromosomes.size(), populationLimit, false); } 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. * @throws NotPositiveException if the population limit is not a positive number (< 1) * @throws NumberIsTooSmallException if the new population size is smaller than the current number * of chromosomes in the population */ public void setPopulationLimit(final int populationLimit) throws NotPositiveException, NumberIsTooSmallException { if (populationLimit <= 0) { throw new NotPositiveException(LocalizedFormats.POPULATION_LIMIT_NOT_POSITIVE, populationLimit); } if (populationLimit < chromosomes.size()) { throw new NumberIsTooSmallException(populationLimit, chromosomes.size(), true); } 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(); } /** * Returns an iterator over the unmodifiable list of chromosomes. * <p>Any call to {@link Iterator#remove()} will result in a {@link UnsupportedOperationException}.</p> * * @return chromosome iterator */ public Iterator<Chromosome> iterator() { return getChromosomes().iterator(); } }