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/*
* 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
*/
public abstract class ListPopulation implements Population {
/** List of chromosomes */
private List 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. emptyList(), populationLimit);
}
/**
* Creates a new ListPopulation instance.
*
* 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 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(populationLimit);
this.chromosomes.addAll(chromosomes);
}
/**
* Sets the list of chromosomes.
*
* Note: this method removes 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 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 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 getChromosomes() {
return Collections.unmodifiableList(chromosomes);
}
/**
* Access the list of chromosomes.
* @return the list of chromosomes
* @since 3.1
*/
protected List 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.
* Any call to {@link Iterator#remove()} will result in a {@link UnsupportedOperationException}.
*
* @return chromosome iterator
*/
public Iterator iterator() {
return getChromosomes().iterator();
}
}