001 /*
002 * Java Genetic Algorithm Library (jenetics-1.6.0).
003 * Copyright (c) 2007-2014 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.internal.util.object.NonNull;
025 import static org.jenetics.internal.util.object.eq;
026
027 import java.util.Deque;
028 import java.util.LinkedList;
029 import java.util.List;
030 import java.util.concurrent.atomic.AtomicInteger;
031
032 import org.jenetics.internal.util.HashBuilder;
033
034 import org.jenetics.util.Array;
035 import org.jenetics.util.Function;
036 import org.jenetics.util.ISeq;
037 import org.jenetics.util.Seq;
038
039 /**
040 * Combines several alterers to one.
041 *
042 * @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
043 * @since 1.0
044 * @version 1.2 — <em>$Date: 2014-03-01 $</em>
045 */
046 public final class CompositeAlterer<G extends Gene<?, G>>
047 extends AbstractAlterer<G>
048 {
049
050 private final ISeq<Alterer<G>> _alterers;
051
052 /**
053 * Combine the given alterers.
054 *
055 * @param alterers the alterers to combine.
056 * @throws NullPointerException if one of the alterers is {@code null}.
057 */
058 public CompositeAlterer(final Seq<Alterer<G>> alterers) {
059 super(1.0);
060
061 alterers.forAll(NonNull("Alterer"));
062 _alterers = normalize(alterers).toISeq();
063 }
064
065 /**
066 * Combine the given alterers.
067 *
068 * @param alterers the alterers to combine.
069 * @throws NullPointerException if one of the alterers is {@code null}.
070 *
071 * @deprecated Use {@link #of(Alterer...)} instead.
072 */
073 @Deprecated
074 @SafeVarargs
075 public CompositeAlterer(final Alterer<G>... alterers) {
076 this(Array.of(alterers));
077 }
078
079 private static <G extends Gene<?, G>>
080 Array<Alterer<G>> normalize(final Seq<Alterer<G>> alterers) {
081 final Deque<Alterer<G>> stack = new LinkedList<>(alterers.asList());
082
083 final List<Alterer<G>> normalized = new LinkedList<>();
084
085 while (!stack.isEmpty()) {
086 final Alterer<G> alterer = stack.pollFirst();
087
088 if (alterer instanceof CompositeAlterer<?>) {
089 final CompositeAlterer<G> calterer = (CompositeAlterer<G>)alterer;
090
091 for (int i = calterer.getAlterers().length(); --i >= 0;) {
092 stack.addFirst(calterer.getAlterers().get(i));
093 }
094 } else {
095 normalized.add(alterer);
096 }
097 }
098
099 return Array.of(normalized);
100 }
101
102 @Override
103 public <C extends Comparable<? super C>>
104 int alter(final Population<G, C> population, final int generation) {
105 final AtomicInteger alterations = new AtomicInteger(0);
106
107 _alterers.forEach(new Function<Alterer<G>, Void>() {
108 @Override public Void apply(final Alterer<G> alterer) {
109 alterations.addAndGet(alterer.alter(population, generation));
110 return null;
111 }
112 });
113
114 return alterations.get();
115 }
116
117 /**
118 * Create a new CompositeAlterer with the given alterer appended.
119 *
120 * @param alterer the alterer to append.
121 * @return a new CompositeAlterer.
122 * @throws NullPointerException if the given alterer is {@code null}.
123 */
124 public CompositeAlterer<G> append(final Alterer<G> alterer) {
125 return CompositeAlterer.valueOf(this, requireNonNull(alterer, "Alterer"));
126 }
127
128 /**
129 * Return the alterers this alterer consists of. The returned array is sealed
130 * and cannot be changed.
131 *
132 * @return the alterers this alterer consists of.
133 */
134 public ISeq<Alterer<G>> getAlterers() {
135 return _alterers;
136 }
137
138 @Override
139 public int hashCode() {
140 return HashBuilder.of(getClass()).and(_alterers).value();
141 }
142
143 @Override
144 public boolean equals(final Object obj) {
145 if (obj == this) {
146 return true;
147 }
148 if (obj == null || obj.getClass() != getClass()) {
149 return false;
150 }
151
152 final CompositeAlterer<?> alterer = (CompositeAlterer<?>)obj;
153 return eq(_alterers, alterer._alterers);
154 }
155
156 @Override
157 public String toString() {
158 return format("%s[%s]", getClass().getSimpleName(), _alterers);
159 }
160
161 /**
162 * Combine the given alterers.
163 *
164 * @param alterers the alterers to combine.
165 * @throws NullPointerException if one of the alterers is {@code null}.
166 *
167 * @deprecated Use {@link #of(Alterer[])} instead.
168 */
169 @Deprecated
170 @SafeVarargs
171 public static <G extends Gene<?, G>>
172 CompositeAlterer<G> valueOf(final Alterer<G>... alterers) {
173 return new CompositeAlterer<>(Array.of(alterers));
174 }
175
176 /**
177 * Combine the given alterers.
178 *
179 * @param alterers the alterers to combine.
180 * @throws NullPointerException if one of the alterers is {@code null}.
181 */
182 @SafeVarargs
183 public static <G extends Gene<?, G>>
184 CompositeAlterer<G> of(final Alterer<G>... alterers) {
185 return new CompositeAlterer<>(Array.of(alterers));
186 }
187
188 /**
189 * Joins the given alterer and returns a new CompositeAlterer object. If one
190 * of the given alterers is a CompositeAlterer the sub alterers of it are
191 * unpacked and appended to the newly created CompositeAlterer.
192 *
193 * @param <T> the gene type of the alterers.
194 * @param a1 the first alterer.
195 * @param a2 the second alterer.
196 * @return a new CompositeAlterer object.
197 * @throws NullPointerException if one of the given alterer is {@code null}.
198 */
199 public static <T extends Gene<?, T>> CompositeAlterer<T> join(
200 final Alterer<T> a1,
201 final Alterer<T> a2
202 ) {
203 return CompositeAlterer.valueOf(a1, a2);
204 }
205 }
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