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 */
020package io.jenetics.util;
021
022import static java.lang.String.format;
023import static io.jenetics.internal.util.Hashes.hash;
024import static io.jenetics.internal.util.SerialIO.readLong;
025import static io.jenetics.internal.util.SerialIO.writeLong;
026
027import java.io.DataInput;
028import java.io.DataOutput;
029import java.io.IOException;
030import java.io.InvalidObjectException;
031import java.io.ObjectInputStream;
032import java.io.Serial;
033import java.io.Serializable;
034import java.util.Optional;
035import java.util.stream.LongStream;
036
037/**
038 * Long 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 */
047public final /*record*/ class LongRange implements Serializable {
048
049        @Serial
050        private static final long serialVersionUID = 2L;
051
052        private final long _min;
053        private final long _max;
054
055        private LongRange(final long min, final long 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 long range.
068         *
069         * @return the minimum value of the long range
070         */
071        public long min() {
072                return _min;
073        }
074
075        /**
076         * Return the maximum value of the long range.
077         *
078         * @return the maximum value of the long range
079         */
080        public long 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 long 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<LongRange> intersect(final LongRange other) {
108                if (_max <= other._min || _min >= other._max) {
109                        return Optional.empty();
110                } else {
111                        return Optional.of(
112                                LongRange.of(
113                                        Math.max(_min, other._min),
114                                        Math.min(_max, other._max)
115                                )
116                        );
117                }
118        }
119
120        /**
121         * Returns a sequential ordered {@code LongStream} from {@link #min()}
122         * (inclusive) to {@link #max()} (exclusive) by an incremental step of
123         * {@code 1}.
124         * <p>
125         * An equivalent sequence of increasing values can be produced sequentially
126         * using a {@code for} loop as follows:
127         * {@snippet lang="java":
128         * for (long i = range.min(); i < range.max(); ++i) {
129         *     // ...
130         * }
131         * }
132         *
133         * @since 3.4
134         *
135         * @return a sequential {@link LongStream} for the range of {@code long}
136         *         elements
137         */
138        public LongStream stream() {
139                return LongStream.range(_min, _max);
140        }
141
142        /**
143         * Create a new {@code LongRange} object with the given {@code min} and
144         * {@code max} values.
145         *
146         * @param min the lower bound of the long range
147         * @param max the upper bound of the long range
148         * @return a new {@code LongRange} object
149         * @throws IllegalArgumentException if {@code min > max}
150         */
151        public static LongRange of(final long min, final long max) {
152                return new LongRange(min, max);
153        }
154
155        /**
156         * Return a new (half-open) range, which contains only the given value:
157         * {@code [value, value + 1)}.
158         *
159         * @since 4.0
160         *
161         * @param value the value of the created (half-open) integer range
162         * @return a new (half-open) range, which contains only the given value
163         */
164        public static LongRange of(final long value) {
165                return of(value, value + 1);
166        }
167
168        @Override
169        public int hashCode() {
170                return hash(_min, hash(_max, hash(getClass())));
171        }
172
173        @Override
174        public boolean equals(final Object obj) {
175                return obj == this ||
176                        obj instanceof LongRange other &&
177                        _min == other._min &&
178                        _max == other._max;
179        }
180
181        @Override
182        public String toString() {
183                return "[" + _min + ", " + _max + "]";
184        }
185
186
187        /* *************************************************************************
188         *  Java object serialization
189         * ************************************************************************/
190
191        @Serial
192        private Object writeReplace() {
193                return new SerialProxy(SerialProxy.LONG_RANGE, this);
194        }
195
196        @Serial
197        private void readObject(final ObjectInputStream stream)
198                throws InvalidObjectException
199        {
200                throw new InvalidObjectException("Serialization proxy required.");
201        }
202
203        void write(final DataOutput out) throws IOException {
204                writeLong(_min, out);
205                writeLong(_max, out);
206        }
207
208        static LongRange read(final DataInput in) throws IOException {
209                return of(readLong(in), readLong(in));
210        }
211
212}