001/*
002 * Units of Measurement API
003 * Copyright (c) 2014-2021, 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.spi;
031
032import javax.measure.Quantity;
033import javax.measure.Quantity.Scale;
034import javax.measure.Unit;
035
036/**
037 * Represents a factory that accepts {@link Number} and {@link Unit} arguments to create {@link Quantity} results.
038 *
039 * @param <Q>
040 *          the type of the {@link Quantity} result
041 *
042 * @author <a href="mailto:werner@uom.technology">Werner Keil</a>
043 * @author <a href="mailto:otaviopolianasantana@gmail.com">Otavio Santana</a>
044 * @version 1.4, December 18, 2018
045 * @since 1.0
046 *
047 * @see <a href="https://en.wikipedia.org/wiki/Factory_method_pattern"> Wikipedia: Factory method pattern</a>
048 * @see Quantity
049 * @see Unit
050 */
051public interface QuantityFactory<Q extends Quantity<Q>> {
052
053    /**
054     * Returns the quantity for the specified number stated in the specified unit and scale.
055     *
056     * @param value
057     *          the numeric value stated in the specified unit
058     * @param unit
059     *          the unit
060     * @param scale
061     *          The {@code ABSOLUTE} / {@code RELATIVE} {@code scale} of this quantity
062     * @return the corresponding quantity
063     * @since 2.0
064     */
065    Quantity<Q> create(Number value, Unit<Q> unit, Scale scale);
066    
067    /**
068     * Returns the quantity for the specified number stated in the specified unit.
069     *
070     * @param value
071     *          the numeric value stated in the specified unit
072     * @param unit
073     *          the unit
074     * @return the corresponding quantity
075     */
076    Quantity<Q> create(Number value, Unit<Q> unit);
077
078    /**
079     * Returns the system unit for quantities produced by this factory or {@code null} if unknown.
080     *
081     * <p>
082     * Because the system unit is unique by quantity type, it can be be used to identify the quantity given the unit. For example:
083     * </p>
084     *
085     * <pre>
086     *     static boolean isAngularSpeed({@literal Unit<?>} unit) {
087     *         return unit.getSystemUnit().equals(RADIAN.divide(SECOND));
088     *     }
089     *     assert isAngularSpeed(REVOLUTION.divide(MINUTE)); // Returns true.
090     * </pre>
091     *
092     * @return the system unit for this factory.
093     * @see Unit#getSystemUnit()
094     */
095    Unit<Q> getSystemUnit();
096}