001/*
002 * Units of Measurement API
003 * Copyright (c) 2014-2015, 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 a {@link Quantity} result.
037 *
038 * <p>This is a <a href="http://docs.oracle.com/javase/8/docs/api/java/util/function/package-summary.html#package.description">functional interface</a>
039 * whose functional method is {@link #create(Number, Unit)}.
040 *
041 * @param <Q> the type of the {@link Quantity} result
042 *
043 * @author <a href="mailto:[email protected]">Werner Keil</a>
044 * @author <a href="mailto:[email protected]">Otavio Santana</a>
045 * @version 0.7, $Date: 2015-09-27 $
046 */
047public interface QuantityFactory <Q extends Quantity<Q>> {
048
049    /**
050     * Returns the quantity for the specified number stated in the specified unit.
051     *
052     * @param number the numeric value stated in the specified unit
053     * @param unit the unit
054     * @return the corresponding quantity
055     */
056        Quantity<Q> create(Number value, Unit<Q> unit);
057        
058    /**
059     * Returns the system unit for quantities produced by this factory
060     * or <code>null</code> if unknown.
061     *
062     * <p>Because the system unit is unique by quantity type, it can be
063     * be used to identify the quantity given the unit. For example:</p>
064     *
065     * <code>
066     *     static boolean isAngularSpeed(Unit<?> unit) {
067     *         return unit.getSystemUnit().equals(RADIAN.divide(SECOND));
068     *     }
069     *     assert isAngularSpeed(REVOLUTION.divide(MINUTE)); // Returns true.
070     * </code>
071     *
072     * @return the system unit for this factory.
073     * @see Unit#getSystemUnit()
074     */
075    Unit<Q> getSystemUnit();
076}