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 io.jenetics.util.RandomRegistry.getRandom;
024
025 import java.io.Serializable;
026 import java.util.Random;
027
028 import io.jenetics.internal.math.random;
029 import io.jenetics.util.ISeq;
030 import io.jenetics.util.IntRange;
031 import io.jenetics.util.MSeq;
032 import io.jenetics.util.Mean;
033
034 /**
035 * NumericGene implementation which holds a 32 bit integer number.
036 *
037 * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html">
038 * value-based</a> class; use of identity-sensitive operations (including
039 * reference equality ({@code ==}), identity hash code, or synchronization) on
040 * instances of {@code IntegerGene} may have unpredictable results and should
041 * be avoided.
042 *
043 * @see IntegerChromosome
044 *
045 * @implSpec
046 * This class is immutable and thread-safe.
047 *
048 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
049 * @since 2.0
050 * @version 4.0
051 */
052 public final class IntegerGene
053 extends AbstractNumericGene<Integer, IntegerGene>
054 implements
055 NumericGene<Integer, IntegerGene>,
056 Mean<IntegerGene>,
057 Comparable<IntegerGene>,
058 Serializable
059 {
060
061 private static final long serialVersionUID = 1L;
062
063 /**
064 * Create a new random {@code IntegerGene} with the given value and the
065 * given range. If the {@code value} isn't within the interval [min, max],
066 * no exception is thrown. In this case the method
067 * {@link IntegerGene#isValid()} returns {@code false}.
068 *
069 * @param value the value of the gene.
070 * @param min the minimal valid value of this gene (inclusively).
071 * @param max the maximal valid value of this gene (inclusively).
072 * @throws NullPointerException if one of the arguments is {@code null}.
073 */
074 IntegerGene(final Integer value, final Integer min, final Integer max) {
075 super(value, min, max);
076 }
077
078 @Override
079 public int compareTo(final IntegerGene other) {
080 return _value.compareTo(other._value);
081 }
082
083 /**
084 * Create a new random {@code IntegerGene} with the given value and the
085 * given range. If the {@code value} isn't within the interval [min, max],
086 * no exception is thrown. In this case the method
087 * {@link IntegerGene#isValid()} returns {@code false}.
088 *
089 * @param value the value of the gene.
090 * @param min the minimal valid value of this gene (inclusively).
091 * @param max the maximal valid value of this gene (inclusively).
092 * @return a new {@code IntegerGene} with the given {@code value}
093 */
094 public static IntegerGene of(final int value, final int min, final int max) {
095 return new IntegerGene(value, min, max);
096 }
097
098 /**
099 * Create a new random {@code IntegerGene} with the given value and the
100 * given range. If the {@code value} isn't within the interval [min, max],
101 * no exception is thrown. In this case the method
102 * {@link IntegerGene#isValid()} returns {@code false}.
103 *
104 * @since 3.2
105 *
106 * @param value the value of the gene.
107 * @param range the integer range to use
108 * @return a new {@code IntegerGene} with the give {@code value}
109 * @throws NullPointerException if the given {@code range} is {@code null}.
110 */
111 public static IntegerGene of(final int value, final IntRange range) {
112 return new IntegerGene(value, range.getMin(), range.getMax());
113 }
114
115 /**
116 * Create a new random {@code IntegerGene}. It is guaranteed that the value of
117 * the {@code IntegerGene} lies in the interval [min, max].
118 *
119 * @param min the minimal valid value of this gene (inclusively).
120 * @param max the maximal valid value of this gene (inclusively).
121 * @return a new random {@code IntegerGene}
122 */
123 public static IntegerGene of(final int min, final int max) {
124 return of(nextInt(getRandom(), min, max), min, max);
125 }
126
127 /**
128 * Create a new random {@code IntegerGene}. It is guaranteed that the value of
129 * the {@code IntegerGene} lies in the interval [min, max].
130 *
131 * @since 3.2
132 *
133 * @param range the integer range to use
134 * @return a new random {@code IntegerGene}
135 * @throws NullPointerException if the given {@code range} is {@code null}.
136 */
137 public static IntegerGene of(final IntRange range) {
138 return of(nextInt(getRandom(), range.getMin(), range.getMax()), range);
139 }
140
141 static ISeq<IntegerGene> seq(
142 final Integer minimum,
143 final Integer maximum,
144 final IntRange lengthRange
145 ) {
146 final int min = minimum;
147 final int max = maximum;
148 final Random r = getRandom();
149
150 return MSeq.<IntegerGene>ofLength(random.nextInt(lengthRange, r))
151 .fill(() -> new IntegerGene(nextInt(r, min, max), minimum, maximum))
152 .toISeq();
153 }
154
155 @Override
156 public IntegerGene newInstance(final Number number) {
157 return new IntegerGene(number.intValue(), _min, _max);
158 }
159
160 @Override
161 public IntegerGene newInstance() {
162 return new IntegerGene(
163 nextInt(getRandom(), _min, _max), _min, _max
164 );
165 }
166
167 @Override
168 public IntegerGene mean(final IntegerGene that) {
169 return new IntegerGene(_value + (that._value - _value)/2, _min, _max);
170 }
171
172 /**
173 * Returns a pseudo-random, uniformly distributed int value between min and
174 * max (min and max included).
175 *
176 * @param random the random engine to use for calculating the random int
177 * value
178 * @param min lower bound for generated integer
179 * @param max upper bound for generated integer
180 * @return a random integer greater than or equal to {@code min} and
181 * less than or equal to {@code max}
182 * @throws IllegalArgumentException if {@code min > max}
183 * @throws NullPointerException if the given {@code random}
184 * engine is {@code null}.
185 */
186 static int nextInt(
187 final Random random,
188 final int min, final int max
189 ) {
190 if (min > max) {
191 throw new IllegalArgumentException(format(
192 "Min >= max: %d >= %d", min, max
193 ));
194 }
195
196 final int diff = max - min + 1;
197 int result = 0;
198
199 if (diff <= 0) {
200 do {
201 result = random.nextInt();
202 } while (result < min || result > max);
203 } else {
204 result = random.nextInt(diff) + min;
205 }
206
207 return result;
208 }
209
210 }
|