001/*
002 * Units of Measurement API
003 * Copyright (c) 2014-2016, 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 javax.measure.spi;
031
032import javax.measure.Quantity;
033import javax.measure.Unit;
034
035/**
036 * Represents a factory that accepts {@linkplain Number} and {@link Unit} arguments to create {@link Quantity} results.
037 *
038 * @param <Q>
039 *          the type of the {@link Quantity} result
040 *
041 * @author <a href="mailto:[email protected]">Werner Keil</a>
042 * @author <a href="mailto:[email protected]">Otavio Santana</a>
043 * @version 1.0, August 8, 2016
044 * @since 1.0
045 * 
046 * @see Quantity
047 */
048public interface QuantityFactory<Q extends Quantity<Q>> {
049
050  /**
051   * Returns the quantity for the specified number stated in the specified unit.
052   *
053   * @param value
054   *          the numeric value stated in the specified unit
055   * @param unit
056   *          the unit
057   * @return the corresponding quantity
058   */
059  Quantity<Q> create(Number value, Unit<Q> unit);
060
061  /**
062   * Returns the system unit for quantities produced by this factory or <code>null</code> if unknown.
063   *
064   * <p>
065   * Because the system unit is unique by quantity type, it can be be used to identify the quantity given the unit. For example:
066   * </p>
067   *
068   * <pre>
069   *     static boolean isAngularSpeed({@literal Unit<?>} unit) {
070   *         return unit.getSystemUnit().equals(RADIAN.divide(SECOND));
071   *     }
072   *     assert isAngularSpeed(REVOLUTION.divide(MINUTE)); // Returns true.
073   * </pre>
074   *
075   * @return the system unit for this factory.
076   * @see Unit#getSystemUnit()
077   */
078  Unit<Q> getSystemUnit();
079}