001/*
002 * Java Genetic Algorithm Library (jenetics-7.1.0).
003 * Copyright (c) 2007-2022 Franz Wilhelmstötter
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * 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 * Author:
018 *    Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com)
019 */
020package io.jenetics;
021
022import static java.util.Objects.requireNonNull;
023import static io.jenetics.internal.util.Hashes.hash;
024
025import java.util.Objects;
026
027import io.jenetics.util.ISeq;
028import io.jenetics.util.Verifiable;
029
030/**
031 * The abstract base implementation of the Chromosome interface. The implementors
032 * of this class must assure that the protected member {@code _genes} is not
033 * {@code null} and the length of the {@code genes} > 0.
034 *
035 * @param <G> the gene type.
036 *
037 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
038 * @since 1.0
039 * @version 5.2
040 */
041public abstract class AbstractChromosome<G extends Gene<?, G>>
042        implements Chromosome<G>
043{
044
045        /**
046         * Array of genes which forms the chromosome. This array must
047         * be initialized by the derived classes.
048         */
049        protected final transient ISeq<G> _genes;
050
051        /**
052         * Indicates whether this chromosome is valid or not. If the variable is
053         * {@code null} the validation state hasn't been calculated yet.
054         */
055        protected transient Boolean _valid = null;
056
057        /**
058         * Create a new {@code AbstractChromosome} from the given {@code genes}
059         * array.
060         *
061         * @param genes the genes that form the chromosome.
062         * @throws NullPointerException if the given gene array is {@code null}.
063         * @throws IllegalArgumentException if the length of the gene sequence is
064         *         empty.
065         */
066        protected AbstractChromosome(final ISeq<? extends G> genes) {
067                requireNonNull(genes, "Gene array");
068                assert genes.forAll(Objects::nonNull) : "Found at least on null gene.";
069
070                if (genes.isEmpty()) {
071                        throw new IllegalArgumentException(
072                                "The genes sequence must contain at least one gene."
073                        );
074                }
075
076                _genes = ISeq.upcast(genes);
077        }
078
079        @Override
080        public G get(final int index) {
081                return _genes.get(index);
082        }
083
084        @Override
085        public int length() {
086                return _genes.length();
087        }
088
089        @Override
090        public boolean isValid() {
091                if (_valid == null) {
092                        _valid = _genes.forAll(Verifiable::isValid);
093                }
094                return _valid;
095        }
096
097        @Override
098        public int hashCode() {
099                return hash(_genes, hash(getClass()));
100        }
101
102        @Override
103        public boolean equals(final Object obj) {
104                return obj == this ||
105                        obj != null &&
106                        getClass() == obj.getClass() &&
107                        Objects.equals(_genes, ((AbstractChromosome<?>)obj)._genes);
108        }
109
110        @Override
111        public String toString() {
112                return Objects.toString(_genes);
113        }
114
115}