001/*
002 * Units of Measurement API
003 * Copyright (c) 2014-2023, 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 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 javax.measure.test.unit;
031
032import javax.measure.Quantity;
033import javax.measure.Unit;
034import javax.measure.test.TestUnit;
035
036/**
037 * Building blocks on top of which all others units are created. Base units are always unscaled metric units.
038 *
039 * <p>
040 * When using the standard model (default), all seven base units are dimensionally independent.
041 * </p>
042 *
043 * @param <Q>
044 *            The type of the quantity measured by this unit.
045 *
046 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
047 * @author <a href="mailto:werner@uom.technology">Werner Keil</a>
048 * @version 1.1
049 * @since 1.0
050 *
051 * @see <a href="http://en.wikipedia.org/wiki/SI_base_unit">Wikipedia: SI base unit</a>
052 */
053public class BaseUnit<Q extends Quantity<Q>> extends TestUnit<Q> {
054    /**
055     * Creates a base unit having the specified symbol.
056     *
057     * @param symbol
058     *            the symbol of this base unit. 
059     * @param name the name of this base unit.
060     * @throws IllegalArgumentException
061     *             if the specified symbol is associated to a different unit.
062     */
063    public BaseUnit(String symbol, String name) {
064        super(name);
065        this.symbol = symbol;
066    }
067
068    /**
069     * Creates a base unit with name and factor
070     *
071     * @param factor
072     *            the factor
073     * @param name the name of this base unit.
074     * @throws IllegalArgumentException
075     *             if the specified symbol is associated to a different unit.
076     */
077    public BaseUnit(String name, double factor) {
078        super(name, factor);
079    }
080
081    /**
082     * Creates a base unit having the specified symbol.
083     *
084     * @param symbol
085     *            the symbol of this base unit.
086     * @throws IllegalArgumentException
087     *             if the specified symbol is associated to a different unit.
088     */
089    public BaseUnit(String symbol) {
090        this(symbol, null);
091    }
092
093    @Override
094    public String getSymbol() {
095        return symbol;
096    }
097
098    @Override
099    public boolean equals(Object obj) {
100        if (this == obj) {
101            return true;
102        }
103        if (obj instanceof BaseUnit<?>) {
104            BaseUnit<?> other = (BaseUnit<?>) obj;
105            return symbol != null && symbol.equals(other.symbol);
106        }
107        return false;
108    }
109
110    @Override
111    public int hashCode() {
112        // return Objects.hashCode(symbol);
113        return 0;
114    }
115
116    @Override
117    public Unit<Q> getSystemUnit() {
118        return this;
119    }
120}