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.engine;
021
022 import static java.lang.String.format;
023 import static java.util.Objects.requireNonNull;
024 import static io.jenetics.internal.util.Hashes.hash;
025 import static io.jenetics.internal.util.SerialIO.readLong;
026 import static io.jenetics.internal.util.SerialIO.writeLong;
027
028 import java.io.IOException;
029 import java.io.InvalidObjectException;
030 import java.io.ObjectInput;
031 import java.io.ObjectInputStream;
032 import java.io.ObjectOutput;
033 import java.io.Serial;
034 import java.io.Serializable;
035 import java.util.Objects;
036
037 import io.jenetics.Gene;
038 import io.jenetics.Genotype;
039 import io.jenetics.internal.util.Requires;
040 import io.jenetics.util.ISeq;
041
042 /**
043 * Represents the initialization value of an evolution stream/iterator.
044 *
045 * @see EvolutionStart
046 * @see EvolutionStreamable#stream(EvolutionInit)
047 *
048 * @param <G> the gene type
049 *
050 * @implNote
051 * This class is immutable and thread-safe.
052 *
053 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
054 * @version 6.0
055 * @since 4.1
056 */
057 public final class EvolutionInit<G extends Gene<?, G>>
058 implements Serializable
059 {
060
061 @Serial
062 private static final long serialVersionUID = 1L;
063
064 private final ISeq<Genotype<G>> _population;
065 private final long _generation;
066
067 private EvolutionInit(
068 final ISeq<Genotype<G>> population,
069 final long generation
070 ) {
071 _population = requireNonNull(population);
072 _generation = Requires.positive(generation);
073 }
074
075 /**
076 * Return the initial population.
077 *
078 * @return the initial population
079 */
080 public ISeq<Genotype<G>> population() {
081 return _population;
082 }
083
084 /**
085 * Return the generation of the start population.
086 *
087 * @return the start generation
088 */
089 public long generation() {
090 return _generation;
091 }
092
093 @Override
094 public int hashCode() {
095 return hash(_generation, hash(_population));
096 }
097
098 @Override
099 public boolean equals(final Object obj) {
100 return obj == this ||
101 obj instanceof EvolutionInit<?> other &&
102 _generation == other._generation &&
103 Objects.equals(_population, other._population);
104 }
105
106 @Override
107 public String toString() {
108 return format(
109 "EvolutionStart[population-size=%d, generation=%d]",
110 _population.size(), _generation
111 );
112 }
113
114 /**
115 * Create a new evolution start object with the given population and for the
116 * given generation.
117 *
118 * @param <G> the gene type
119 * @param population the start population.
120 * @param generation the start generation of the population
121 * @return a new evolution start object
122 * @throws java.lang.NullPointerException if the given {@code population} is
123 * {@code null}.
124 * @throws IllegalArgumentException if the given {@code generation} is
125 * smaller then one
126 */
127 public static <G extends Gene<?, G>>
128 EvolutionInit<G> of(
129 final ISeq<Genotype<G>> population,
130 final long generation
131 ) {
132 return new EvolutionInit<>(population, generation);
133 }
134
135
136 /* *************************************************************************
137 * Java object serialization
138 * ************************************************************************/
139
140 @Serial
141 private Object writeReplace() {
142 return new SerialProxy(SerialProxy.EVOLUTION_INIT, this);
143 }
144
145 @Serial
146 private void readObject(final ObjectInputStream stream)
147 throws InvalidObjectException
148 {
149 throw new InvalidObjectException("Serialization proxy required.");
150 }
151
152 void write(final ObjectOutput out) throws IOException {
153 out.writeObject(_population);
154 writeLong(_generation, out);
155 }
156
157 @SuppressWarnings({"unchecked", "rawtypes"})
158 static Object read(final ObjectInput in)
159 throws IOException, ClassNotFoundException
160 {
161 return new EvolutionInit(
162 (ISeq)in.readObject(),
163 readLong(in)
164 );
165 }
166
167 }
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