001/* 002 * Units of Measurement Reference Implementation 003 * Copyright (c) 2005-2020, Units of Measurement project. 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; 036import javax.measure.UnitConverter; 037 038/** 039 * Unit specialized for the Java SE platform. It extends {@link Unit} with 040 * {@linkplain Comparable} and {@linkplain Serializable } 041 * 042 * @see {@link Unit} 043 * @author werner 044 * @param <Q> 045 * @version 1.4, July 2, 2019 046 * @since 1.0.9 047 */ 048public interface ComparableUnit<Q extends Quantity<Q>> extends Unit<Q>, Comparable<Unit<Q>>, Serializable { 049 050 /** 051 * Compares two instances of {@code Unit<Q>}, doing the conversion of unit if necessary. 052 * 053 * @param that the {@code Unit<Q>} to be compared with this instance. 054 * @return {@code true} if {@code that < this}. 055 * @throws NullPointerException if the unit is null 056 * 057 * @see <a href= "https://dictionary.cambridge.org/dictionary/english/equivalent">Cambridge Dictionary: equivalent</a> 058 * @see <a href= "https://www.lexico.com/en/definition/equivalent">LEXICO: equivalent</a> 059 */ 060 boolean isEquivalentTo(Unit<Q> that); 061 062 /** 063 * Indicates if this unit belongs to the set of coherent SI units (unscaled SI 064 * units). 065 * 066 * The base and coherent derived units of the SI form a coherent set, designated 067 * the set of coherent SI units. The word coherent is used here in the following 068 * sense: when coherent units are used, equations between the numerical values 069 * of quantities take exactly the same form as the equations between the 070 * quantities themselves. Thus if only units from a coherent set are used, 071 * conversion factors between units are never required. 072 * 073 * @return <code>equals(toSystemUnit())</code> 074 */ 075 boolean isSystemUnit(); 076 077 /** 078 * Returns the system unit (unscaled SI unit) from which this unit is derived. 079 * They can be be used to identify a quantity given the unit. For example:<br> 080 * <code> static boolean isAngularVelocity(AbstractUnit<?> unit) {<br> return unit.getSystemUnit().equals(RADIAN.divide(SECOND));<br>} 081 * <br>assert(REVOLUTION.divide(MINUTE).isAngularVelocity()); // Returns true. </code> 082 * 083 * @return the unscaled metric unit from which this unit is derived. 084 */ 085 Unit<Q> getSystemUnit(); 086 087 /** 088 * Returns the converter from this unit to its unscaled {@link #toSystemUnit 089 * System Unit} unit. 090 * 091 * @return <code>getConverterTo(this.toSystemUnit())</code> 092 * @see #toSystemUnit 093 */ 094 UnitConverter getSystemConverter(); 095}