001/*
002 * Units of Measurement Reference Implementation
003 * Copyright (c) 2005-2023, 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.unit;
031
032import java.util.Map;
033import java.util.Objects;
034
035import javax.measure.Dimension;
036import javax.measure.Quantity;
037import javax.measure.Unit;
038import javax.measure.UnitConverter;
039
040import tech.units.indriya.AbstractUnit;
041import tech.uom.lib.common.function.UnitConverterSupplier;
042
043/**
044 * <p>
045 * This class represents the units derived from other units using {@linkplain UnitConverter converters}.
046 * </p>
047 *
048 * <p>
049 * Examples of transformed units:<code>
050 *         CELSIUS = KELVIN.shift(273.15);
051 *         FOOT = METRE.multiply(3048).divide(10000);
052 *         MILLISECOND = MILLI(SECOND);
053 *     </code>
054 * </p>
055 *
056 * <p>
057 * Transformed units have no symbol. But like any other units, they may have labels attached to them (see
058 * {@link javax.measure.format.UnitFormat#label(Unit, String) UnitFormat.label}
059 * </p>
060 *
061 * <p>
062 * Instances of this class are created through the {@link AbstractUnit#transform} method.
063 * </p>
064 *
065 * @param <Q>
066 *          The type of the quantity measured by this unit.
067 *
068 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
069 * @author <a href="mailto:werner@units.tech">Werner Keil</a>
070 * @version 2.0, March 1, 2020
071 * @since 1.0
072 */
073public final class TransformedUnit<Q extends Quantity<Q>> extends AbstractUnit<Q> implements UnitConverterSupplier {
074
075  /**
076     *
077     */
078  private static final long serialVersionUID = 1L;
079
080  /**
081   * Holds the parent unit.
082   */
083  private final AbstractUnit<Q> parentUnit;
084
085  /**
086   * Holds the system unit.
087   */
088  private final Unit<Q> systemUnit;
089
090  /**
091   * Holds the converter to the parent unit.
092   */
093  private final UnitConverter converter;
094
095  /**
096   * Creates a transformed unit from the specified system unit. using the parent as symbol
097   * 
098   * @param parentUnit
099   *          the system unit from which this unit is derived.
100   * @param converter
101   *          the converter to the parent units.
102   */
103  public TransformedUnit(Unit<Q> parentUnit, UnitConverter unitConverter) {
104    this(null, parentUnit, unitConverter);
105  }
106
107  /**
108   * Creates a transformed unit from the specified parent unit.
109   *
110   * @param symbol
111   *          the symbol to use with this transformed unit.
112   * @param name
113   *          the name to use with this transformed unit.
114   * @param parentUnit
115   *          the parent unit from which this unit is derived.
116   * @param unitConverter
117   *          the converter to the parent units.
118   * @since 2.0
119   */
120  public TransformedUnit(String symbol, String name, Unit<Q> parentUnit, UnitConverter unitConverter) {
121    this(symbol, name, parentUnit, parentUnit.getSystemUnit(), unitConverter);
122  }
123  
124  /**
125   * Creates a transformed unit from the specified parent unit.
126   *
127   * @param symbol
128   *          the symbol to use with this transformed unit.
129   * @param parentUnit
130   *          the parent unit from which this unit is derived.
131   * @param unitConverter
132   *          the converter to the parent units.
133   */
134  public TransformedUnit(String symbol, Unit<Q> parentUnit, UnitConverter unitConverter) {
135    this(symbol, parentUnit, parentUnit.getSystemUnit(), unitConverter);
136  }
137
138  /**
139   * Creates a transformed unit from the specified parent and system unit. using a specific symbol and name.
140   * 
141   * @param symbol
142   *          the symbol for this unit.
143   * @param name
144   *          the name for this unit.
145   * @param parentUnit
146   *          the parent unit from which this unit is derived.
147   * @param sysUnit
148   *          the system unit which this unit is based on.
149   * @param converter
150   *          the converter to the parent units.
151   * @since 2.0
152   */
153  public TransformedUnit(String symbol, String name, Unit<Q> parentUnit, Unit<Q> sysUnit, UnitConverter unitConverter) {
154    if (parentUnit instanceof AbstractUnit) {
155      final AbstractUnit<Q> abParent = (AbstractUnit<Q>) parentUnit;
156
157      this.systemUnit = sysUnit;
158      // if (!abParent.isSystemUnit()) {
159      // throw new IllegalArgumentException("The parent unit: " + abParent
160      // + " is not a system unit");
161      // }
162      this.parentUnit = abParent;
163      this.converter = unitConverter;
164      setSymbol(symbol);
165      // see https://github.com/unitsofmeasurement/uom-se/issues/54
166      setName(name);
167    } else {
168      throw new IllegalArgumentException("The parent unit: " + parentUnit + " is not an abstract unit.");
169    }
170  }
171  
172  /**
173   * Creates a transformed unit from the specified parent and system unit. using a specific symbol.
174   * 
175   * @param symbol
176   *          the symbol for this unit.
177   * @param parentUnit
178   *          the parent unit from which this unit is derived.
179   * @param sysUnit
180   *          the system unit which this unit is based on.
181   * @param converter
182   *          the converter to the parent units.
183   */
184  public TransformedUnit(String symbol, Unit<Q> parentUnit, Unit<Q> sysUnit, UnitConverter unitConverter) {
185          this(symbol, null, parentUnit, sysUnit, unitConverter);
186  }
187
188  @Override
189  public Dimension getDimension() {
190    return parentUnit.getDimension();
191  }
192
193  @Override
194  public UnitConverter getSystemConverter() {
195    return parentUnit.getSystemConverter().concatenate(converter);
196  }
197
198  /**
199   * Returns the converter to the parent unit.
200   *
201   * @return the converter to the parent unit.
202   */
203  @Override
204  public UnitConverter getConverter() {
205    return converter;
206  }
207
208  @Override
209  protected Unit<Q> toSystemUnit() {
210    return (systemUnit != null ? systemUnit : parentUnit.getSystemUnit());
211  }
212
213  @Override
214  public Map<? extends Unit<?>, Integer> getBaseUnits() {
215    return parentUnit.getBaseUnits();
216  }
217
218  @Override
219  public int hashCode() {
220    return Objects.hash(parentUnit, converter);
221  }
222
223  @Override
224  public boolean equals(Object obj) {
225    if (this == obj) {
226      return true;
227    }
228    if (obj instanceof TransformedUnit) {
229      TransformedUnit<?> other = (TransformedUnit<?>) obj;
230      return Objects.equals(parentUnit, other.parentUnit) 
231                  && Objects.equals(converter, other.converter);
232    } 
233    return false;
234  }
235
236  /**
237   * Returns the parent unit for this unit. The parent unit is the untransformed unit from which this unit is derived.
238   *
239   * @return the untransformed unit from which this unit is derived.
240   */
241  public Unit<Q> getParentUnit() {
242    return parentUnit;
243  }
244}