001/*
002 * Java Genetic Algorithm Library (jenetics-8.1.0).
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 */
020package io.jenetics;
021
022import io.jenetics.util.BaseSeq;
023import io.jenetics.util.Factory;
024import io.jenetics.util.ISeq;
025import io.jenetics.util.Verifiable;
026
027/**
028 * A chromosome consists of one or more genes. It also provides a factory
029 * method for creating new, random chromosome instances of the same type and the
030 * same constraint.
031 *
032 * @implSpec
033 * Implementations of the {@code Chromosome} interface must be <em>immutable</em>
034 * and guarantee efficient random access ({@code O(1)}) to the genes. A
035 * {@code Chromosome} must contains at least one {@code Gene}.
036 *
037 * @see <a href="http://en.wikipedia.org/wiki/Chromosome">Wikipedia: Chromosome</a>
038 * @see Genotype
039 * @see Gene
040 *
041 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
042 * @since 1.0
043 * @version 6.0
044 */
045public interface Chromosome<G extends Gene<?, G>>
046        extends
047                BaseSeq<G>,
048                Factory<Chromosome<G>>,
049                Verifiable
050{
051
052        /**
053         * Return the first gene of this chromosome. Each chromosome must contain
054         * at least one gene.
055         *
056         * @since 5.2
057         *
058         * @return the first gene of this chromosome.
059         */
060        default G gene() {
061                return get(0);
062        }
063
064        @Override
065        default boolean isValid() {
066                return stream().allMatch(Gene::isValid);
067        }
068
069        /**
070         * A factory method which creates a new {@link Chromosome} of specific type
071         * and the given {@code genes}.
072         *
073         * @param genes the genes of the new chromosome. The given genes array is
074         *         not copied.
075         * @return A new {@link Chromosome} of the same type with the given genes.
076         * @throws NullPointerException if the given {@code gene}s are {@code null}.
077         * @throws IllegalArgumentException if the length of the given gene sequence
078         *        is smaller than one.
079         */
080        Chromosome<G> newInstance(final ISeq<G> genes);
081
082        /**
083         * Casts this {@code Chromosome} to an instance of type {@code C}.
084         * This is a convenient method for an ordinary cast and allows seamless
085         * method-chaining. Instead of
086         * {@snippet lang="java":
087         * final Genotype<BitGene> gt = null; // @replace substring='null' replacement="..."
088         * final int count = ((BitChromosome)gt.chromosome()).bitCount();
089         * }
090         * you can write
091         * {@snippet lang="java":
092         * final Genotype<BitGene> gt = null; // @replace substring='null' replacement="..."
093         * final int count = gt.chromosome()
094         *     .as(BitChromosome.class)
095         *     .bitCount();
096         * }
097         * This may lead to a more elegant programming style in some cases.
098         *
099         * @since 3.7
100         *
101         * @param type the target type class
102         * @param <C> the target chromosome type
103         * @return this chromosome cast as {@code C}
104         * @throws NullPointerException if the target type class is {@code null}
105         * @throws ClassCastException if this chromosome can't be cast to a
106         *         chromosome of type {@code C}
107         */
108        default <C extends Chromosome<G>> C as(final Class<C> type) {
109                return type.cast(this);
110        }
111
112}