001 /*
002 * Java Genetic Algorithm Library (jenetics-2.0.2).
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 2.0 — <em>$Date: 2014-03-30 $</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 private static <G extends Gene<?, G>>
066 Array<Alterer<G>> normalize(final Seq<Alterer<G>> alterers) {
067 final Deque<Alterer<G>> stack = new LinkedList<>(alterers.asList());
068
069 final List<Alterer<G>> normalized = new LinkedList<>();
070
071 while (!stack.isEmpty()) {
072 final Alterer<G> alterer = stack.pollFirst();
073
074 if (alterer instanceof CompositeAlterer<?>) {
075 final CompositeAlterer<G> calterer = (CompositeAlterer<G>)alterer;
076
077 for (int i = calterer.getAlterers().length(); --i >= 0;) {
078 stack.addFirst(calterer.getAlterers().get(i));
079 }
080 } else {
081 normalized.add(alterer);
082 }
083 }
084
085 return Array.of(normalized);
086 }
087
088 @Override
089 public <C extends Comparable<? super C>>
090 int alter(final Population<G, C> population, final int generation) {
091 final AtomicInteger alterations = new AtomicInteger(0);
092
093 _alterers.forEach(new Function<Alterer<G>, Void>() {
094 @Override public Void apply(final Alterer<G> alterer) {
095 alterations.addAndGet(alterer.alter(population, generation));
096 return null;
097 }
098 });
099
100 return alterations.get();
101 }
102
103 /**
104 * Create a new CompositeAlterer with the given alterer appended.
105 *
106 * @param alterer the alterer to append.
107 * @return a new CompositeAlterer.
108 * @throws NullPointerException if the given alterer is {@code null}.
109 */
110 public CompositeAlterer<G> append(final Alterer<G> alterer) {
111 return CompositeAlterer.of(this, requireNonNull(alterer, "Alterer"));
112 }
113
114 /**
115 * Return the alterers this alterer consists of. The returned array is sealed
116 * and cannot be changed.
117 *
118 * @return the alterers this alterer consists of.
119 */
120 public ISeq<Alterer<G>> getAlterers() {
121 return _alterers;
122 }
123
124 @Override
125 public int hashCode() {
126 return HashBuilder.of(getClass()).and(_alterers).value();
127 }
128
129 @Override
130 public boolean equals(final Object obj) {
131 if (obj == this) {
132 return true;
133 }
134 if (obj == null || obj.getClass() != getClass()) {
135 return false;
136 }
137
138 final CompositeAlterer<?> alterer = (CompositeAlterer<?>)obj;
139 return eq(_alterers, alterer._alterers);
140 }
141
142 @Override
143 public String toString() {
144 return format("%s[%s]", getClass().getSimpleName(), _alterers);
145 }
146
147 /**
148 * Combine the given alterers.
149 *
150 * @param <G> the gene type
151 * @param alterers the alterers to combine.
152 * @return a new alterer which consists of the given one
153 * @throws NullPointerException if one of the alterers is {@code null}.
154 */
155 @SafeVarargs
156 public static <G extends Gene<?, G>>
157 CompositeAlterer<G> of(final Alterer<G>... alterers) {
158 return new CompositeAlterer<>(Array.of(alterers));
159 }
160
161 /**
162 * Joins the given alterer and returns a new CompositeAlterer object. If one
163 * of the given alterers is a CompositeAlterer the sub alterers of it are
164 * unpacked and appended to the newly created CompositeAlterer.
165 *
166 * @param <T> the gene type of the alterers.
167 * @param a1 the first alterer.
168 * @param a2 the second alterer.
169 * @return a new CompositeAlterer object.
170 * @throws NullPointerException if one of the given alterer is {@code null}.
171 */
172 public static <T extends Gene<?, T>> CompositeAlterer<T> join(
173 final Alterer<T> a1,
174 final Alterer<T> a2
175 ) {
176 return CompositeAlterer.of(a1, a2);
177 }
178 }
|