001 /*
002 * Java Genetic Algorithm Library (jenetics-4.2.0).
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.util;
021
022 import static java.lang.String.format;
023
024 import java.io.Serializable;
025 import java.util.stream.IntStream;
026
027 /**
028 * Integer range class.
029 *
030 * @implNote
031 * This class is immutable and thread-safe.
032 *
033 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
034 * @version 3.2
035 * @since 3.2
036 */
037 public final class IntRange implements Serializable {
038
039 private static final long serialVersionUID = 1L;
040
041 private final int _min;
042 private final int _max;
043
044 private IntRange(final int min, final int max) {
045 if (min > max) {
046 throw new IllegalArgumentException(format(
047 "Min greater than max: %s > %s", min, max
048 ));
049 }
050
051 _min = min;
052 _max = max;
053 }
054
055 /**
056 * Return the minimum value of the integer range.
057 *
058 * @return the minimum value of the integer range
059 */
060 public int getMin() {
061 return _min;
062 }
063
064 /**
065 * Return the maximum value of the integer range.
066 *
067 * @return the maximum value of the integer range
068 */
069 public int getMax() {
070 return _max;
071 }
072
073 /**
074 * Return the size of the {@code IntRange}: {@code max - min}.
075 *
076 * @since 3.9
077 *
078 * @return the size of the int range
079 */
080 public int size() {
081 return _max - _min;
082 }
083
084 /**
085 * Returns a sequential ordered {@code IntStream} from {@link #getMin()}
086 * (inclusive) to {@link #getMax()} (exclusive) by an incremental step of
087 * {@code 1}.
088 * <p>
089 * An equivalent sequence of increasing values can be produced sequentially
090 * using a {@code for} loop as follows:
091 * <pre>{@code
092 * for (int i = range.getMin(); i < range.getMax(); ++i) {
093 * ...
094 * }
095 * }</pre>
096 *
097 * @since 3.4
098 *
099 * @return a sequential {@link IntStream} for the range of {@code int}
100 * elements
101 */
102 public IntStream stream() {
103 return IntStream.range(_min, _max);
104 }
105
106 /**
107 * Create a new {@code IntRange} object with the given {@code min} and
108 * {@code max} values.
109 *
110 * @param min the lower bound of the integer range
111 * @param max the upper bound of the integer range
112 * @return a new {@code IntRange} object
113 * @throws IllegalArgumentException if {@code min > max}
114 */
115 public static IntRange of(final int min, final int max) {
116 return new IntRange(min, max);
117 }
118
119 /**
120 * Return a new (half open) range, which contains only the given value:
121 * {@code [value, value + 1)}.
122 *
123 * @since 4.0
124 *
125 * @param value the value of the created (half open) integer range
126 * @return a new (half open) range, which contains only the given value
127 */
128 public static IntRange of(final int value) {
129 return of(value, value + 1);
130 }
131
132 @Override
133 public int hashCode() {
134 return _min + 31*_max;
135 }
136
137 @Override
138 public boolean equals(final Object obj) {
139 return obj == this ||
140 obj instanceof IntRange &&
141 _min == ((IntRange)obj)._min &&
142 _max == ((IntRange)obj)._max;
143 }
144
145 @Override
146 public String toString() {
147 return "[" + _min + ", " + _max + "]";
148 }
149
150 }
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