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Jenetics - Java Genetic Algorithm Library
There is a newer version: 3.6.0
/*
 * Java Genetic Algorithm Library (jenetics-3.2.0).
 * Copyright (c) 2007-2015 Franz Wilhelmstötter
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Author:
 *    Franz Wilhelmstötter ([email protected])
 */
package org.jenetics;

import static java.util.Objects.requireNonNull;
import static org.jenetics.internal.util.Equality.eq;

import java.io.Serializable;
import java.util.Iterator;
import java.util.Objects;
import java.util.RandomAccess;

import org.jenetics.internal.util.Equality;
import org.jenetics.internal.util.Hash;
import org.jenetics.internal.util.reflect;

import org.jenetics.util.ISeq;
import org.jenetics.util.Verifiable;

/**
 * The abstract base implementation of the Chromosome interface. The implementors
 * of this class must assure that the protected member {@code _genes} is not
 * {@code null} and the length of the {@code genes} > 0.
 *
 * @param  the gene type.
 *
 * @author Franz Wilhelmstötter
 * @since 1.0
 * @version 2.0
 */
public abstract class AbstractChromosome>
	implements
		Chromosome,
		RandomAccess,
		Serializable
{
	private static final long serialVersionUID = 1L;

	/**
	 * Array of genes which forms the chromosome. This array must
	 * be initialized by the derived classes.
	 */
	protected transient ISeq _genes = null;

	/**
	 * Indicates whether this chromosome is valid or not. If the variable is
	 * {@code null} the validation state hasn't been calculated yet.
	 */
	protected transient Boolean _valid = null;

	/**
	 * Create a new {@code AbstractChromosome} from the given {@code genes}
	 * array. The genes array is not copied, but sealed, so changes to the given
	 * genes array doesn't effect the genes of this chromosome.
	 *
	 * @param genes the genes that form the chromosome.
	 * @throws NullPointerException if the given gene array is {@code null}.
	 * @throws IllegalArgumentException if the length of the gene array is
	 *          smaller than one.
	 */
	protected AbstractChromosome(final ISeq genes) {
		requireNonNull(genes, "Gene array");
		assert genes.forAll(Objects::nonNull) : "Found at least on null gene.";

		if (genes.length() == 0) {
			throw new IllegalArgumentException(
				"The genes sequence must contain at least one gene."
			);
		}

		_genes = reflect.cast(genes);
	}

	@Override
	public G getGene(final int index) {
		return _genes.get(index);
	}

	@Override
	public ISeq toSeq() {
		return _genes;
	}

	@Override
	public boolean isValid() {
		if (_valid == null) {
			_valid = _genes.forAll(Verifiable::isValid);
		}

		return _valid;
	}

	@Override
	public Iterator iterator() {
		return _genes.iterator();
	}

	@Override
	public int length() {
		return _genes.length();
	}

	@Override
	public int hashCode() {
		return Hash.of(getClass()).and(_genes).value();
	}

	@Override
	public boolean equals(final Object obj) {
		return Equality.of(this, obj).test(ch -> eq(_genes, ch._genes));
	}

	@Override
	public String toString() {
		return _genes.toString();
	}

}