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.prog.op;
021
022 import static java.lang.Double.doubleToLongBits;
023 import static java.lang.Float.floatToIntBits;
024
025 import java.math.BigDecimal;
026 import java.math.BigInteger;
027 import java.util.Objects;
028
029 /**
030 * This is the <em>sealed</em> base class for unmodifiable values. The only
031 * subclasses of this type are {@link Const} and {@link EphemeralConst}.
032 *
033 * @see Const
034 * @see EphemeralConst
035 *
036 * @param <T> the type of the constant value
037 *
038 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
039 * @version 7.0
040 * @since 5.0
041 */
042 public abstract sealed class Val<T>
043 implements Op<T>
044 permits Const, EphemeralConst
045 {
046
047 private final String _name;
048
049 Val(final String name) {
050 _name = name;
051 }
052
053 @Override
054 public final String name() {
055 return _name;
056 }
057
058 /**
059 * Return the constant value.
060 *
061 * @return the constant value
062 */
063 public abstract T value();
064
065 /**
066 * The apply method will always return the {@link #value()}.
067 *
068 * @param value the input parameters will be ignored
069 * @return always {@link #value()}
070 */
071 @Override
072 public final T apply(final T[] value) {
073 return value();
074 }
075
076 /**
077 * The arity of {@code Val} objects is always zero.
078 *
079 * @return always zero
080 */
081 @Override
082 public final int arity() {
083 return 0;
084 }
085
086 @Override
087 public final int hashCode() {
088 return Objects.hashCode(value());
089 }
090
091 @Override
092 public final boolean equals(final Object obj) {
093 return obj == this ||
094 obj instanceof Val<?> other &&
095 equals(other.value(), value());
096 }
097
098 private static boolean equals(final Object a, final Object b) {
099 if (a instanceof Double aa && b instanceof Double bb) {
100 return doubleToLongBits(aa) == doubleToLongBits(bb);
101 } else if (a instanceof Float aa && b instanceof Float bb) {
102 return floatToIntBits(aa) == floatToIntBits(bb);
103 } else if (a instanceof BigDecimal aa && b instanceof BigDecimal bb) {
104 return aa.compareTo(bb) == 0;
105 } else if (a instanceof BigInteger aa && b instanceof BigInteger bb) {
106 return aa.compareTo(bb) == 0;
107 }
108
109 return Objects.equals(a, b);
110 }
111
112 }
|