/*
 * Units of Measurement API
 * Copyright (c) 2014-2015, Jean-Marie Dautelle, Werner Keil, V2COM.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions
 *    and the following disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of JSR-363 nor the names of its contributors may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package javax.measure.spi;

import java.util.Set;

import javax.measure.Dimension;
import javax.measure.Quantity;
import javax.measure.Unit;

/**
 * A system of units grouped together for historical or cultural reasons.<br>
 * Common system of units are "SI" (System International), "Imperial" (British),
 * "US" (US Customary).
 * Nothing prevents a unit from belonging to several systems of units at the
 * same time (for example an {@code Imperial} system would have many of the
 * units held by the {@code US} Customary system).
 *
 * @author <a href="mailto:[email protected]">Jean-Marie Dautelle</a>
 * @author <a href="mailto:[email protected]">Werner Keil</a>
 * @version 0.8.1, 2015-10-26
 * @see <a href="http://en.wikipedia.org/wiki/International_System_of_Units">
 *      Wikipedia: International System of Units</a>
 * @see <a href="http://en.wikipedia.org/wiki/Systems_of_measurement">
 *      Wikipedia: System of measurement</a>
 *
 */
public interface SystemOfUnits {

        /**
         * @return a name
         */
        String getName();

        /**
         * Returns the default unit for the specified quantity.
         *
         * @param <Q>
         *            the compile-time quantity type.
         * @param quantityType
         *            the quantity type.
         * @return the unit for the specified quantity.
         */
        <Q extends Quantity<Q>> Unit<Q> getUnit(Class<Q> quantityType);

        /**
         * Returns a read only view over the units explicitly defined by this system. 
         * This include the base and derived units which are assigned a special name and symbol. 
         * This set does not include new units created by arithmetic or other operations.
         *
         * @return the defined collection of units.
         */
        Set<? extends Unit<?>> getUnits();

        /**
         * Returns the units defined in this system having the specified dimension
         * (convenience method).
         *
         * @param dimension
         *            the dimension of the units to be returned.
         * @return the collection of units of specified dimension.
         */
        Set<? extends Unit<?>> getUnits(Dimension dimension);
}