001 /*
002 * Java Genetic Algorithm Library (jenetics-1.5.0).
003 * Copyright (c) 2007-2013 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@gmx.at)
019 */
020 package org.jenetics;
021
022 import static java.lang.String.format;
023 import static java.util.Objects.requireNonNull;
024 import static org.jenetics.util.object.NonNull;
025 import static org.jenetics.util.object.eq;
026 import static org.jenetics.util.object.hashCodeOf;
027
028 import java.util.Deque;
029 import java.util.LinkedList;
030 import java.util.List;
031 import java.util.concurrent.atomic.AtomicInteger;
032
033 import org.jenetics.util.Array;
034 import org.jenetics.util.Function;
035 import org.jenetics.util.ISeq;
036 import org.jenetics.util.Seq;
037
038 /**
039 * Combines several alterers to one.
040 *
041 * @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
042 * @since 1.0
043 * @version 1.2 — <em>$Date: 2013-09-02 $</em>
044 */
045 public final class CompositeAlterer<G extends Gene<?, G>>
046 extends AbstractAlterer<G>
047 {
048
049 private final ISeq<Alterer<G>> _alterers;
050
051 /**
052 * Combine the given alterers.
053 *
054 * @param alterers the alterers to combine.
055 * @throws NullPointerException if one of the alterers is {@code null}.
056 */
057 public CompositeAlterer(final Seq<Alterer<G>> alterers) {
058 super(1.0);
059
060 alterers.forAll(NonNull("Alterer"));
061 _alterers = normalize(alterers).toISeq();
062 }
063
064 /**
065 * Combine the given alterers.
066 *
067 * @param alterers the alterers to combine.
068 * @throws NullPointerException if one of the alterers is {@code null}.
069 *
070 * @deprecated Use {@link #valueOf(Alterer...)} instead.
071 */
072 @Deprecated
073 @SafeVarargs
074 public CompositeAlterer(final Alterer<G>... alterers) {
075 this(Array.valueOf(alterers));
076 }
077
078 private static <G extends Gene<?, G>>
079 Array<Alterer<G>> normalize(final Seq<Alterer<G>> alterers) {
080 final Deque<Alterer<G>> stack = new LinkedList<>(alterers.asList());
081
082 final List<Alterer<G>> normalized = new LinkedList<>();
083
084 while (!stack.isEmpty()) {
085 final Alterer<G> alterer = stack.pollFirst();
086
087 if (alterer instanceof CompositeAlterer<?>) {
088 final CompositeAlterer<G> calterer = (CompositeAlterer<G>)alterer;
089
090 for (int i = calterer.getAlterers().length(); --i >= 0;) {
091 stack.addFirst(calterer.getAlterers().get(i));
092 }
093 } else {
094 normalized.add(alterer);
095 }
096 }
097
098 return Array.valueOf(normalized);
099 }
100
101 @Override
102 public <C extends Comparable<? super C>>
103 int alter(final Population<G, C> population, final int generation) {
104 final AtomicInteger alterations = new AtomicInteger(0);
105
106 _alterers.forEach(new Function<Alterer<G>, Void>() {
107 @Override public Void apply(final Alterer<G> alterer) {
108 alterations.addAndGet(alterer.alter(population, generation));
109 return null;
110 }
111 });
112
113 return alterations.get();
114 }
115
116 /**
117 * Create a new CompositeAlterer with the given alterer appended.
118 *
119 * @param alterer the alterer to append.
120 * @return a new CompositeAlterer.
121 * @throws NullPointerException if the given alterer is {@code null}.
122 */
123 public CompositeAlterer<G> append(final Alterer<G> alterer) {
124 return CompositeAlterer.valueOf(this, requireNonNull(alterer, "Alterer"));
125 }
126
127 /**
128 * Return the alterers this alterer consists of. The returned array is sealed
129 * and cannot be changed.
130 *
131 * @return the alterers this alterer consists of.
132 */
133 public ISeq<Alterer<G>> getAlterers() {
134 return _alterers;
135 }
136
137 @Override
138 public int hashCode() {
139 return hashCodeOf(getClass()).and(_alterers).value();
140 }
141
142 @Override
143 public boolean equals(final Object obj) {
144 if (obj == this) {
145 return true;
146 }
147 if (obj == null || obj.getClass() != getClass()) {
148 return false;
149 }
150
151 final CompositeAlterer<?> alterer = (CompositeAlterer<?>)obj;
152 return eq(_alterers, alterer._alterers);
153 }
154
155 @Override
156 public String toString() {
157 return format("%s[%s]", getClass().getSimpleName(), _alterers);
158 }
159
160 /**
161 * Combine the given alterers.
162 *
163 * @param alterers the alterers to combine.
164 * @throws NullPointerException if one of the alterers is {@code null}.
165 */
166 @SafeVarargs
167 public static <G extends Gene<?, G>>
168 CompositeAlterer<G> valueOf(final Alterer<G>... alterers) {
169 return new CompositeAlterer<>(Array.valueOf(alterers));
170 }
171
172 /**
173 * Joins the given alterer and returns a new CompositeAlterer object. If one
174 * of the given alterers is a CompositeAlterer the sub alterers of it are
175 * unpacked and appended to the newly created CompositeAlterer.
176 *
177 * @param <T> the gene type of the alterers.
178 * @param a1 the first alterer.
179 * @param a2 the second alterer.
180 * @return a new CompositeAlterer object.
181 * @throws NullPointerException if one of the given alterer is {@code null}.
182 */
183 public static <T extends Gene<?, T>> CompositeAlterer<T> join(
184 final Alterer<T> a1,
185 final Alterer<T> a2
186 ) {
187 return CompositeAlterer.valueOf(a1, a2);
188 }
189 }
190
191
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193
194
195
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