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.math.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 $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $
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         */
040        public AbstractListChromosome(final List<T> representation) {
041            try {
042                checkValidity(representation);
043            } catch (InvalidRepresentationException e) {
044                throw new IllegalArgumentException(String.format("Invalid representation for %s", getClass().getSimpleName()), e);
045            }
046            this.representation = Collections.unmodifiableList(new ArrayList<T> (representation));
047        }
048    
049        /**
050         * Constructor.
051         * @param representation inner representation of the chromosome
052         */
053        public AbstractListChromosome(final T[] representation) {
054            this(Arrays.asList(representation));
055        }
056    
057        /**
058         *
059         * Asserts that <code>representation</code> can represent a valid chromosome.
060         * @param chromosomeRepresentation representation of the chromosome
061         * @throws InvalidRepresentationException iff the <code>representation</code> can not represent
062         *         a valid chromosome
063         */
064        protected abstract void checkValidity(List<T> chromosomeRepresentation) throws InvalidRepresentationException;
065    
066        /**
067         * Returns the (immutable) inner representation of the chromosome.
068         * @return the representation of the chromosome
069         */
070        protected List<T> getRepresentation() {
071            return representation;
072        }
073    
074        /**
075         * Returns the length of the chromosome.
076         * @return the length of the chromosome
077         */
078        public int getLength() {
079            return getRepresentation().size();
080        }
081    
082        /**
083         * Creates a new instance of the same class as <code>this</code> is, with a
084         * given <code>arrayRepresentation</code>. This is needed in crossover and
085         * mutation operators, where we need a new instance of the same class, but
086         * with different array representation.
087         *
088         * Usually, this method just calls a constructor of the class.
089         *
090         * @param chromosomeRepresentation
091         *            the inner array representation of the new chromosome.
092         * @return new instance extended from FixedLengthChromosome with the given
093         *         arrayRepresentation
094         */
095        public abstract AbstractListChromosome<T> newFixedLengthChromosome(final List<T> chromosomeRepresentation);
096    
097        /**
098         * {@inheritDoc}
099         */
100        @Override
101        public String toString() {
102            return String.format("(f=%s %s)", getFitness(), getRepresentation());
103        }
104    }