001/*
002 * Units of Measurement Reference Implementation
003 * Copyright (c) 2005-2018, Jean-Marie Dautelle, Werner Keil, Otavio Santana.
004 *
005 * All rights reserved.
006 *
007 * Redistribution and use in source and binary forms, with or without modification,
008 * are permitted provided that the following conditions are met:
009 *
010 * 1. Redistributions of source code must retain the above copyright notice,
011 *    this list of conditions and the following disclaimer.
012 *
013 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions
014 *    and the following disclaimer in the documentation and/or other materials provided with the distribution.
015 *
016 * 3. Neither the name of JSR-385, Indriya nor the names of their contributors may be used to endorse or promote products
017 *    derived from this software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
020 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
021 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
022 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
023 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
026 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
028 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package tech.units.indriya.function;
031
032import java.math.BigDecimal;
033import java.math.MathContext;
034import java.util.Objects;
035
036import javax.measure.UnitConverter;
037
038import tech.units.indriya.AbstractConverter;
039import tech.uom.lib.common.function.DoubleFactorSupplier;
040import tech.uom.lib.common.function.ValueSupplier;
041
042/**
043 * <p>
044 * This class represents a converter multiplying numeric values by a constant
045 * scaling factor (<code>double</code> based).
046 * </p>
047 * 
048 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
049 * @author <a href="mailto:units@catmedia.us">Werner Keil</a>
050 * @version 1.1, Apr 18, 2018
051 * @since 1.0
052 */
053public final class MultiplyConverter extends AbstractConverter implements ValueSupplier<Double>, DoubleFactorSupplier {
054
055        /**
056         * 
057         */
058        private static final long serialVersionUID = 6588759878444545649L;
059
060        /**
061         * Holds the scale factor.
062         */
063        private final double factor;
064
065        /**
066         * Creates a multiply converter with the specified scale factor.
067         * 
068         * @param factor
069         *            the scaling factor.
070         */
071        public MultiplyConverter(double factor) {
072                this.factor = factor;
073        }
074
075        /**
076         * Creates a multiply converter with the specified scale factor.
077         * 
078         * @param factor
079         *            the scaling factor.
080         */
081        public static MultiplyConverter of(double factor) {
082                return new MultiplyConverter(factor);
083        }
084
085        /**
086         * Returns the scale factor of this converter.
087         * 
088         * @return the scale factor.
089         */
090        public double getFactor() {
091                return factor;
092        }
093
094        @Override
095        public boolean isIdentity() {
096                return factor == 1.0;
097        }
098
099        @Override
100        protected boolean isSimpleCompositionWith(AbstractConverter that) {
101                return that instanceof MultiplyConverter;
102        }
103
104        @Override
105        protected AbstractConverter simpleCompose(AbstractConverter that) {
106                return new MultiplyConverter(factor * ((MultiplyConverter) that).factor);
107        }
108
109        @Override
110        public MultiplyConverter inverseWhenNotIdentity() {
111                return new MultiplyConverter(1.0 / factor);
112        }
113
114        @Override
115        public double convertWhenNotIdentity(double value) {
116                return value * factor;
117        }
118
119        @Override
120        public BigDecimal convertWhenNotIdentity(BigDecimal value, MathContext ctx) throws ArithmeticException {
121                return value.multiply(BigDecimal.valueOf(factor), ctx);
122        }
123
124        @Override
125        public final String transformationLiteral() {
126                return String.format("x -> x * %s", factor);
127        }
128
129        @Override
130        public boolean equals(Object obj) {
131                if (this == obj) {
132                        return true;
133                }
134                if (obj instanceof MultiplyConverter) {
135                        MultiplyConverter that = (MultiplyConverter) obj;
136                        return Objects.equals(factor, that.factor);
137                }
138                return false;
139        }
140
141        @Override
142        public int hashCode() {
143                return Objects.hashCode(factor);
144        }
145
146        @Override
147        public boolean isLinear() {
148                return true;
149        }
150
151        @Override
152        public Double getValue() {
153                return factor;
154        }
155
156        @Override
157        public int compareTo(UnitConverter o) {
158                if (this == o) {
159                        return 0;
160                }
161                if (o instanceof MultiplyConverter) {
162                        return getValue().compareTo(((MultiplyConverter) o).getValue());
163                }
164                return -1;
165        }
166}