001/*
002 * Units of Measurement Implementation for Java SE
003 * Copyright (c) 2005-2017, Jean-Marie Dautelle, Werner Keil, V2COM.
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-363 nor the names of its 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 tec.uom.se.function;
031
032import javax.measure.UnitConverter;
033
034import tec.uom.lib.common.function.DoubleFactorSupplier;
035import tec.uom.lib.common.function.ValueSupplier;
036import tec.uom.se.AbstractConverter;
037
038import java.math.BigDecimal;
039import java.math.MathContext;
040import java.util.Objects;
041
042/**
043 * <p>
044 * This class represents a converter multiplying numeric values by a constant scaling factor (<code>double</code> based).
045 * </p>
046 * 
047 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
048 * @author <a href="mailto:units@catmedia.us">Werner Keil</a>
049 * @version 1.0, Oct 11, 2016
050 * @since 1.0
051 */
052public final class MultiplyConverter extends AbstractConverter implements ValueSupplier<Double>, DoubleFactorSupplier {
053
054  /**
055   * 
056   */
057  private static final long serialVersionUID = 6588759878444545649L;
058
059  /**
060   * Holds the scale factor.
061   */
062  private double factor;
063
064  /**
065   * Creates a multiply converter with the specified scale factor.
066   * 
067   * @param factor
068   *          the scaling factor.
069   * @throws IllegalArgumentException
070   *           if coefficient is <code>1.0</code> (would result in identity converter)
071   */
072  public MultiplyConverter(double factor) {
073    if (factor == 1.0)
074      throw new IllegalArgumentException("Would result in identity converter");
075    this.factor = factor;
076  }
077
078  /**
079   * Returns the scale factor of this converter.
080   * 
081   * @return the scale factor.
082   */
083  public double getFactor() {
084    return factor;
085  }
086
087  @Override
088  public UnitConverter concatenate(UnitConverter converter) {
089    if (!(converter instanceof MultiplyConverter))
090      return super.concatenate(converter);
091    double newfactor = factor * ((MultiplyConverter) converter).factor;
092    return newfactor == 1.0 ? IDENTITY : new MultiplyConverter(newfactor);
093  }
094
095  @Override
096  public MultiplyConverter inverse() {
097    return new MultiplyConverter(1.0 / factor);
098  }
099
100  @Override
101  public double convert(double value) {
102    return value * factor;
103  }
104
105  @Override
106  public BigDecimal convert(BigDecimal value, MathContext ctx) throws ArithmeticException {
107    return value.multiply(BigDecimal.valueOf(factor), ctx);
108  }
109
110  @Override
111  public final String toString() {
112    return MultiplyConverter.class.getSimpleName() + "(" + factor + ")";
113  }
114
115  @Override
116  public boolean equals(Object obj) {
117    if (this == obj) {
118      return true;
119    }
120    if (obj instanceof MultiplyConverter) {
121      MultiplyConverter that = (MultiplyConverter) obj;
122      return Objects.equals(factor, that.factor);
123    }
124    return false;
125  }
126
127  @Override
128  public int hashCode() {
129    return Objects.hashCode(factor);
130  }
131
132  @Override
133  public boolean isLinear() {
134    return true;
135  }
136
137  @Override
138  public Double getValue() {
139    return factor;
140  }
141}