CompositeAlterer.java
/*
* Java Genetic Algorithm Library (@__identifier__@).
* Copyright (c) @__year__@ 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 (franz.wilhelmstoetter@gmx.at)
*/
package org.jenetics;
import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
import static org.jenetics.internal.util.object.NonNull;
import static org.jenetics.internal.util.object.eq;
import java.util.Deque;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import org.jenetics.internal.util.HashBuilder;
import org.jenetics.util.Array;
import org.jenetics.util.Function;
import org.jenetics.util.ISeq;
import org.jenetics.util.Seq;
/**
* Combines several alterers to one.
*
* @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
* @since 1.0
* @version 1.2 — <em>$Date: 2014-03-01 $</em>
*/
public final class CompositeAlterer<G extends Gene<?, G>>
extends AbstractAlterer<G>
{
private final ISeq<Alterer<G>> _alterers;
/**
* Combine the given alterers.
*
* @param alterers the alterers to combine.
* @throws NullPointerException if one of the alterers is {@code null}.
*/
public CompositeAlterer(final Seq<Alterer<G>> alterers) {
super(1.0);
alterers.forAll(NonNull("Alterer"));
_alterers = normalize(alterers).toISeq();
}
/**
* Combine the given alterers.
*
* @param alterers the alterers to combine.
* @throws NullPointerException if one of the alterers is {@code null}.
*
* @deprecated Use {@link #of(Alterer...)} instead.
*/
@Deprecated
@SafeVarargs
public CompositeAlterer(final Alterer<G>... alterers) {
this(Array.of(alterers));
}
private static <G extends Gene<?, G>>
Array<Alterer<G>> normalize(final Seq<Alterer<G>> alterers) {
final Deque<Alterer<G>> stack = new LinkedList<>(alterers.asList());
final List<Alterer<G>> normalized = new LinkedList<>();
while (!stack.isEmpty()) {
final Alterer<G> alterer = stack.pollFirst();
if (alterer instanceof CompositeAlterer<?>) {
final CompositeAlterer<G> calterer = (CompositeAlterer<G>)alterer;
for (int i = calterer.getAlterers().length(); --i >= 0;) {
stack.addFirst(calterer.getAlterers().get(i));
}
} else {
normalized.add(alterer);
}
}
return Array.of(normalized);
}
@Override
public <C extends Comparable<? super C>>
int alter(final Population<G, C> population, final int generation) {
final AtomicInteger alterations = new AtomicInteger(0);
_alterers.forEach(new Function<Alterer<G>, Void>() {
@Override public Void apply(final Alterer<G> alterer) {
alterations.addAndGet(alterer.alter(population, generation));
return null;
}
});
return alterations.get();
}
/**
* Create a new CompositeAlterer with the given alterer appended.
*
* @param alterer the alterer to append.
* @return a new CompositeAlterer.
* @throws NullPointerException if the given alterer is {@code null}.
*/
public CompositeAlterer<G> append(final Alterer<G> alterer) {
return CompositeAlterer.valueOf(this, requireNonNull(alterer, "Alterer"));
}
/**
* Return the alterers this alterer consists of. The returned array is sealed
* and cannot be changed.
*
* @return the alterers this alterer consists of.
*/
public ISeq<Alterer<G>> getAlterers() {
return _alterers;
}
@Override
public int hashCode() {
return HashBuilder.of(getClass()).and(_alterers).value();
}
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (obj == null || obj.getClass() != getClass()) {
return false;
}
final CompositeAlterer<?> alterer = (CompositeAlterer<?>)obj;
return eq(_alterers, alterer._alterers);
}
@Override
public String toString() {
return format("%s[%s]", getClass().getSimpleName(), _alterers);
}
/**
* Combine the given alterers.
*
* @param alterers the alterers to combine.
* @throws NullPointerException if one of the alterers is {@code null}.
*
* @deprecated Use {@link #of(Alterer[])} instead.
*/
@Deprecated
@SafeVarargs
public static <G extends Gene<?, G>>
CompositeAlterer<G> valueOf(final Alterer<G>... alterers) {
return new CompositeAlterer<>(Array.of(alterers));
}
/**
* Combine the given alterers.
*
* @param alterers the alterers to combine.
* @throws NullPointerException if one of the alterers is {@code null}.
*/
@SafeVarargs
public static <G extends Gene<?, G>>
CompositeAlterer<G> of(final Alterer<G>... alterers) {
return new CompositeAlterer<>(Array.of(alterers));
}
/**
* Joins the given alterer and returns a new CompositeAlterer object. If one
* of the given alterers is a CompositeAlterer the sub alterers of it are
* unpacked and appended to the newly created CompositeAlterer.
*
* @param <T> the gene type of the alterers.
* @param a1 the first alterer.
* @param a2 the second alterer.
* @return a new CompositeAlterer object.
* @throws NullPointerException if one of the given alterer is {@code null}.
*/
public static <T extends Gene<?, T>> CompositeAlterer<T> join(
final Alterer<T> a1,
final Alterer<T> a2
) {
return CompositeAlterer.valueOf(a1, a2);
}
}