001 /*
002 * Java Genetic Algorithm Library (jenetics-8.0.0).
003 * Copyright (c) 2007-2024 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 */
020 package io.jenetics;
021
022 import static java.util.Objects.requireNonNull;
023 import static io.jenetics.internal.util.Hashes.hash;
024
025 import java.util.Objects;
026
027 import io.jenetics.util.ISeq;
028 import 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 */
041 public 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 }
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