001 /*
002 * Java Genetic Algorithm Library (jenetics-4.1.0).
003 * Copyright (c) 2007-2018 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;
021
022 import static java.lang.String.format;
023 import static java.util.Objects.requireNonNull;
024
025 import java.io.Serializable;
026 import java.util.Objects;
027 import java.util.Random;
028 import java.util.function.Function;
029
030 /**
031 * Represents the result pair of one of the four {@code Mutator.mutate} calls.
032 *
033 * @see Mutator#mutate(Phenotype, long, double, Random)
034 * @see Mutator#mutate(Genotype, double, Random)
035 * @see Mutator#mutate(Chromosome, double, Random)
036 * @see Mutator#mutate(Gene, Random)
037 *
038 * @implSpec
039 * This class is immutable and thread-safe.
040 *
041 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
042 * @version 4.0
043 * @since 4.0
044 */
045 public final class MutatorResult<T> implements Serializable {
046
047 private static final long serialVersionUID = 1L;
048
049 private final T _result;
050 private final int _mutations;
051
052 private MutatorResult(final T result, final int mutations) {
053 if (mutations < 0) {
054 throw new IllegalArgumentException(
055 "Mutations must not be negative: " + mutations
056 );
057 }
058
059 _result = requireNonNull(result);
060 _mutations = mutations;
061 }
062
063 /**
064 * Maps this mutation result to type {@code B} using the given {@code mapper}.
065 *
066 * @param mapper the mutation result mapper
067 * @param <B> the new mutation result type
068 * @return a new mapped mutation result
069 * @throws NullPointerException if the given {@code mapper} is {@code null}
070 */
071 <B> MutatorResult<B> map(final Function<? super T, ? extends B> mapper) {
072 requireNonNull(mapper);
073 return of(mapper.apply(_result), _mutations);
074 }
075
076 /**
077 * Return the mutation result.
078 *
079 * @return the mutation result
080 */
081 public T getResult() {
082 return _result;
083 }
084
085 /**
086 * Return the number of mutations for this mutation result.
087 *
088 * @return the number of mutations
089 */
090 public int getMutations() {
091 return _mutations;
092 }
093
094 /**
095 * Create a new mutation result with the given values.
096 *
097 * @param result the mutation result
098 * @param mutations the number of mutations
099 * @param <T> the mutation result type
100 * @return a new mutation result
101 * @throws IllegalArgumentException if the given {@code mutations} is
102 * negative
103 * @throws NullPointerException if the given mutation result is {@code null}
104 */
105 public static <T> MutatorResult<T> of(final T result, final int mutations) {
106 return new MutatorResult<>(result, mutations);
107 }
108
109 /**
110 * Create a new mutation result with the given result. The number of
111 * mutations is set to zero.
112 *
113 * @param result the mutation result
114 * @param <T> the mutation result type
115 * @return a new mutation result
116 * @throws NullPointerException if the given mutation result is {@code null}
117 */
118 public static <T> MutatorResult<T> of(final T result) {
119 return new MutatorResult<>(result, 0);
120 }
121
122 @Override
123 public int hashCode() {
124 int hash = 17;
125 hash += 37*Objects.hashCode(_result) + 31;
126 hash += 37*_mutations + 31;
127 return hash;
128 }
129
130 @Override
131 public boolean equals(final Object obj) {
132 return obj == this ||
133 obj instanceof MutatorResult<?> &&
134 Objects.equals(((MutatorResult)obj)._result, _result) &&
135 ((MutatorResult)obj)._mutations == _mutations;
136 }
137
138 @Override
139 public String toString() {
140 return format("MutatorResult[%s, %s]", _result, _mutations);
141 }
142
143 }
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