001 /*
002 * Java Genetic Algorithm Library (jenetics-7.1.0).
003 * Copyright (c) 2007-2022 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.stream.IntStream;
035
036 /**
037 * Integer range class.
038 *
039 * @implNote
040 * This class is immutable and thread-safe.
041 *
042 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
043 * @version 6.0
044 * @since 3.2
045 */
046 public final /*record*/ class IntRange implements Serializable {
047
048 @Serial
049 private static final long serialVersionUID = 2L;
050
051 private final int _min;
052 private final int _max;
053
054 private IntRange(final int min, final int max) {
055 if (min > max) {
056 throw new IllegalArgumentException(format(
057 "Min greater than max: %s > %s", min, max
058 ));
059 }
060
061 _min = min;
062 _max = max;
063 }
064
065 /**
066 * Return the minimum value of the integer range.
067 *
068 * @return the minimum value of the integer range
069 */
070 public int min() {
071 return _min;
072 }
073
074 /**
075 * Return the maximum value of the integer range.
076 *
077 * @return the maximum value of the integer range
078 */
079 public int max() {
080 return _max;
081 }
082
083 /**
084 * Return the size of the {@code IntRange}: {@code max - min}.
085 *
086 * @since 3.9
087 *
088 * @return the size of the int range
089 */
090 public int size() {
091 return _max - _min;
092 }
093
094 /**
095 * Returns a sequential ordered {@code IntStream} from {@link #min()}
096 * (inclusive) to {@link #max()} (exclusive) by an incremental step of
097 * {@code 1}.
098 * <p>
099 * An equivalent sequence of increasing values can be produced sequentially
100 * using a {@code for} loop as follows:
101 * <pre>{@code
102 * for (int i = range.min(); i < range.max(); ++i) {
103 * ...
104 * }
105 * }</pre>
106 *
107 * @since 3.4
108 *
109 * @return a sequential {@link IntStream} for the range of {@code int}
110 * elements
111 */
112 public IntStream stream() {
113 return IntStream.range(_min, _max);
114 }
115
116 /**
117 * Create a new {@code IntRange} object with the given {@code min} and
118 * {@code max} values.
119 *
120 * @param min the lower bound of the integer range
121 * @param max the upper bound of the integer range
122 * @return a new {@code IntRange} object
123 * @throws IllegalArgumentException if {@code min > max}
124 */
125 public static IntRange of(final int min, final int max) {
126 return new IntRange(min, max);
127 }
128
129 /**
130 * Return a new (half open) range, which contains only the given value:
131 * {@code [value, value + 1)}.
132 *
133 * @since 4.0
134 *
135 * @param value the value of the created (half open) integer range
136 * @return a new (half open) range, which contains only the given value
137 */
138 public static IntRange of(final int value) {
139 return of(value, value + 1);
140 }
141
142 @Override
143 public int hashCode() {
144 return hash(_min, hash(_max));
145 }
146
147 @Override
148 public boolean equals(final Object obj) {
149 return obj == this ||
150 obj instanceof IntRange other &&
151 _min == other._min &&
152 _max == other._max;
153 }
154
155 @Override
156 public String toString() {
157 return "[" + _min + ", " + _max + "]";
158 }
159
160
161 /* *************************************************************************
162 * Java object serialization
163 * ************************************************************************/
164
165 @Serial
166 private Object writeReplace() {
167 return new SerialProxy(SerialProxy.INT_RANGE, this);
168 }
169
170 @Serial
171 private void readObject(final ObjectInputStream stream)
172 throws InvalidObjectException
173 {
174 throw new InvalidObjectException("Serialization proxy required.");
175 }
176
177 void write(final DataOutput out) throws IOException {
178 writeInt(_min, out);
179 writeInt(_max, out);
180 }
181
182 static IntRange read(final DataInput in) throws IOException {
183 return of(readInt(in), readInt(in));
184 }
185
186 }
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