001 /*
002 * Java Genetic Algorithm Library (jenetics-8.0.0).
003 * Copyright (c) 2007-2024 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.util;
021
022 import static java.lang.String.format;
023 import static io.jenetics.internal.util.Hashes.hash;
024 import static io.jenetics.internal.util.SerialIO.readInt;
025 import static io.jenetics.internal.util.SerialIO.writeInt;
026
027 import java.io.DataInput;
028 import java.io.DataOutput;
029 import java.io.IOException;
030 import java.io.InvalidObjectException;
031 import java.io.ObjectInputStream;
032 import java.io.Serial;
033 import java.io.Serializable;
034 import java.util.Optional;
035 import java.util.stream.IntStream;
036
037 /**
038 * Integer range class.
039 *
040 * @implNote
041 * This class is immutable and thread-safe.
042 *
043 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
044 * @version 6.0
045 * @since 3.2
046 */
047 public final /*record*/ class IntRange implements Serializable {
048
049 @Serial
050 private static final long serialVersionUID = 2L;
051
052 private final int _min;
053 private final int _max;
054
055 private IntRange(final int min, final int max) {
056 if (min > max) {
057 throw new IllegalArgumentException(format(
058 "Min greater than max: %s > %s", min, max
059 ));
060 }
061
062 _min = min;
063 _max = max;
064 }
065
066 /**
067 * Return the minimum value of the integer range.
068 *
069 * @return the minimum value of the integer range
070 */
071 public int min() {
072 return _min;
073 }
074
075 /**
076 * Return the maximum value of the integer range.
077 *
078 * @return the maximum value of the integer range
079 */
080 public int max() {
081 return _max;
082 }
083
084 /**
085 * Checks whether the given {@code value} is within the range
086 * {@code [min, max)}.
087 *
088 * @since 8.0
089 *
090 * @param value the value to check
091 * @return {@code true} if the {@code value} is with the range
092 * {@code [min, max)}, {@code false} otherwise
093 */
094 public boolean contains(final int value) {
095 return value >= _min && value < _max;
096 }
097
098 /**
099 * Return the intersection of {@code this} range with the {@code other}.
100 *
101 * @since 8.0
102 *
103 * @param other the intersection range or {@link Optional#empty()} if there
104 * is none
105 * @return the range intersection
106 */
107 public Optional<IntRange> intersect(final IntRange other) {
108 if (_max <= other._min || _min >= other._max) {
109 return Optional.empty();
110 } else {
111 return Optional.of(
112 IntRange.of(
113 Math.max(_min, other._min),
114 Math.min(_max, other._max)
115 )
116 );
117 }
118 }
119
120 /**
121 * Return the size of the {@code IntRange}: {@code max - min}.
122 *
123 * @since 3.9
124 *
125 * @return the size of the int range
126 */
127 public int size() {
128 return _max - _min;
129 }
130
131 /**
132 * Returns a sequential ordered {@code IntStream} from {@link #min()}
133 * (inclusive) to {@link #max()} (exclusive) by an incremental step of
134 * {@code 1}.
135 * <p>
136 * An equivalent sequence of increasing values can be produced sequentially
137 * using a {@code for} loop as follows:
138 * {@snippet lang="java":
139 * for (int i = range.min(); i < range.max(); ++i) {
140 * // ...
141 * }
142 * }
143 *
144 * @since 3.4
145 *
146 * @return a sequential {@link IntStream} for the range of {@code int}
147 * elements
148 */
149 public IntStream stream() {
150 return IntStream.range(_min, _max);
151 }
152
153 /**
154 * Create a new {@code IntRange} object with the given {@code min} and
155 * {@code max} values.
156 *
157 * @param min the lower bound of the integer range
158 * @param max the upper bound of the integer range
159 * @return a new {@code IntRange} object
160 * @throws IllegalArgumentException if {@code min > max}
161 */
162 public static IntRange of(final int min, final int max) {
163 return new IntRange(min, max);
164 }
165
166 /**
167 * Return a new (half-open) range, which contains only the given value:
168 * {@code [value, value + 1)}.
169 *
170 * @since 4.0
171 *
172 * @param value the value of the created (half-open) integer range
173 * @return a new (half-open) range, which contains only the given value
174 */
175 public static IntRange of(final int value) {
176 return of(value, value + 1);
177 }
178
179 @Override
180 public int hashCode() {
181 return hash(_min, hash(_max));
182 }
183
184 @Override
185 public boolean equals(final Object obj) {
186 return obj == this ||
187 obj instanceof IntRange other &&
188 _min == other._min &&
189 _max == other._max;
190 }
191
192 @Override
193 public String toString() {
194 return "[" + _min + ", " + _max + "]";
195 }
196
197
198 /* *************************************************************************
199 * Java object serialization
200 * ************************************************************************/
201
202 @Serial
203 private Object writeReplace() {
204 return new SerialProxy(SerialProxy.INT_RANGE, this);
205 }
206
207 @Serial
208 private void readObject(final ObjectInputStream stream)
209 throws InvalidObjectException
210 {
211 throw new InvalidObjectException("Serialization proxy required.");
212 }
213
214 void write(final DataOutput out) throws IOException {
215 writeInt(_min, out);
216 writeInt(_max, out);
217 }
218
219 static IntRange read(final DataInput in) throws IOException {
220 return of(readInt(in), readInt(in));
221 }
222
223 }
|