    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017    package org.apache.commons.math3.genetics;
    018
    019    import java.util.ArrayList;
    020    import java.util.Arrays;
    021    import java.util.Collections;
    022    import java.util.List;
    023
    024    /**
    025     * Chromosome represented by an immutable list of a fixed length.
    026     *
    027     * @param <T> type of the representation list
    028     * @version $Id: AbstractListChromosome.java 1416643 2012-12-03 19:37:14Z tn $
    029     * @since 2.0
    030     */
    031    public abstract class AbstractListChromosome<T> extends Chromosome {
    032
    033        /** List representing the chromosome */
    034        private final List<T> representation;
    035
    036        /**
    037         * Constructor.
    038         * @param representation inner representation of the chromosome
    039         * @throws InvalidRepresentationException iff the <code>representation</code> can not represent a valid chromosome
    040         */
    041        public AbstractListChromosome(final List<T> representation) throws InvalidRepresentationException {
    042            checkValidity(representation);
    043            this.representation = Collections.unmodifiableList(new ArrayList<T> (representation));
    044        }
    045
    046        /**
    047         * Constructor.
    048         * @param representation inner representation of the chromosome
    049         * @throws InvalidRepresentationException iff the <code>representation</code> can not represent a valid chromosome
    050         */
    051        public AbstractListChromosome(final T[] representation) throws InvalidRepresentationException {
    052            this(Arrays.asList(representation));
    053        }
    054
    055        /**
    056         * Asserts that <code>representation</code> can represent a valid chromosome.
    057         *
    058         * @param chromosomeRepresentation representation of the chromosome
    059         * @throws InvalidRepresentationException iff the <code>representation</code> can not represent a valid chromosome
    060         */
    061        protected abstract void checkValidity(List<T> chromosomeRepresentation) throws InvalidRepresentationException;
    062
    063        /**
    064         * Returns the (immutable) inner representation of the chromosome.
    065         * @return the representation of the chromosome
    066         */
    067        protected List<T> getRepresentation() {
    068            return representation;
    069        }
    070
    071        /**
    072         * Returns the length of the chromosome.
    073         * @return the length of the chromosome
    074         */
    075        public int getLength() {
    076            return getRepresentation().size();
    077        }
    078
    079        /**
    080         * Creates a new instance of the same class as <code>this</code> is, with a given <code>arrayRepresentation</code>.
    081         * This is needed in crossover and mutation operators, where we need a new instance of the same class, but with
    082         * different array representation.
    083         * <p>
    084         * Usually, this method just calls a constructor of the class.
    085         *
    086         * @param chromosomeRepresentation the inner array representation of the new chromosome.
    087         * @return new instance extended from FixedLengthChromosome with the given arrayRepresentation
    088         */
    089        public abstract AbstractListChromosome<T> newFixedLengthChromosome(final List<T> chromosomeRepresentation);
    090
    091        @Override
    092        public String toString() {
    093            return String.format("(f=%s %s)", getFitness(), getRepresentation());
    094        }
    095    }