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;
031
032import java.io.Serializable;
033
034import javax.measure.Quantity;
035import javax.measure.Unit;
036
037/**
038 * Unit specialized for the Java SE platform. It extends {@link Unit} with {@linkplain Comparable} and {@linkplain Serializable }
039 * 
040 * @see {@link Unit}
041 * @author werner
042 * @param <Q>
043 * @since 1.0.9
044 */
045public interface ComparableUnit<Q extends Quantity<Q>> extends Unit<Q>, Comparable<Unit<Q>>, Serializable {
046
047  /**
048   * Compares two instances of {@link Unit <Q>}, doing the conversion of unit if necessary.
049   *
050   * @param that
051   *          the {@code Unit<Q>} to be compared with this instance.
052   * @return {@code true} if {@code that < this}.
053   * @throws NullPointerException
054   *           if the unit is null
055   */
056  boolean isEquivalentOf(Unit<Q> that);
057
058  /**
059   * Indicates if this unit belongs to the set of coherent SI units (unscaled SI units).
060   * 
061   * The base and coherent derived units of the SI form a coherent set, designated the set of coherent SI units. The word coherent is used here in the
062   * following sense: when coherent units are used, equations between the numerical values of quantities take exactly the same form as the equations
063   * between the quantities themselves. Thus if only units from a coherent set are used, conversion factors between units are never required.
064   * 
065   * @return <code>equals(toSystemUnit())</code>
066   */
067  boolean isSystemUnit();
068}