001/*
002 * Java Genetic Algorithm Library (jenetics-9.1.0).
003 * Copyright (c) 2007-2026 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;
023
024import java.util.Objects;
025
026import io.jenetics.util.ISeq;
027import io.jenetics.util.Verifiable;
028
029/**
030 * The abstract base implementation of the Chromosome interface. The implementors
031 * of this class must assure that the protected member {@code _genes} is not
032 * {@code null} and the length of the {@code genes} > 0.
033 *
034 * @param <G> the gene type.
035 *
036 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
037 * @since 1.0
038 * @version 5.2
039 */
040public abstract class AbstractChromosome<G extends Gene<?, G>>
041        implements Chromosome<G>
042{
043
044        /**
045         * Array of genes which forms the chromosome. This array must
046         * be initialized by the derived classes.
047         */
048        protected final transient ISeq<G> _genes;
049
050        /**
051         * Indicates whether this chromosome is valid or not. If the variable is
052         * {@code null} the validation state hasn't been calculated yet.
053         */
054        protected transient Boolean _valid = null;
055
056        /**
057         * Create a new {@code AbstractChromosome} from the given {@code genes}
058         * array.
059         *
060         * @param genes the genes that form the chromosome.
061         * @throws NullPointerException if the given gene array is {@code null}.
062         * @throws IllegalArgumentException if the length of the gene sequence is
063         *         empty.
064         */
065        protected AbstractChromosome(final ISeq<? extends G> genes) {
066                requireNonNull(genes, "Gene array");
067                assert genes.forAll(Objects::nonNull) : "Found at least on null gene.";
068
069                if (genes.isEmpty()) {
070                        throw new IllegalArgumentException(
071                                "The genes sequence must contain at least one gene."
072                        );
073                }
074
075                _genes = ISeq.upcast(genes);
076        }
077
078        @Override
079        public G get(final int index) {
080                return _genes.get(index);
081        }
082
083        @Override
084        public int length() {
085                return _genes.length();
086        }
087
088        @Override
089        public boolean isValid() {
090                if (_valid == null) {
091                        _valid = _genes.forAll(Verifiable::isValid);
092                }
093                return _valid;
094        }
095
096        @Override
097        public int hashCode() {
098                return _genes.hashCode();
099        }
100
101        @Override
102        public boolean equals(final Object obj) {
103                return obj != null &&
104                        getClass() == obj.getClass() &&
105                        Objects.equals(_genes, ((AbstractChromosome<?>)obj)._genes);
106        }
107
108        @Override
109        public String toString() {
110                return Objects.toString(_genes);
111        }
112
113}