Source code

001/*
002 * Units of Measurement Reference Implementation
003 * Copyright (c) 2005-2018, 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, 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.quantity;
031
032import static tech.units.indriya.unit.Units.*;
033
034import java.lang.reflect.InvocationHandler;
035import java.lang.reflect.Method;
036import java.lang.reflect.Proxy;
037import java.util.HashMap;
038import java.util.Map;
039import java.util.concurrent.ConcurrentHashMap;
040import java.util.logging.Level;
041import java.util.logging.Logger;
042
043import javax.measure.Quantity;
044import javax.measure.Unit;
045import javax.measure.quantity.*;
046import javax.measure.spi.QuantityFactory;
047
048import tech.units.indriya.AbstractQuantity;
049import tech.units.indriya.AbstractUnit;
050
051/**
052 * A factory producing simple quantities instances (tuples {@link Number}/{@link Unit}). This implementation of {@link QuantityFactory} uses the
053 * DynamicProxy features of Java reflection API.<br>
054 * <br>
055 *
056 * For example:<br>
057 * <code>
058 *      Quantity<Mass> m = ProxyQuantityFactory.getInstance(Mass.class).create(23.0, KILOGRAM); // 23.0 kg<br/>
059 *      Quantity<Time> t = ProxyQuantityFactory.getInstance(Time.class).create(124, MILLI(SECOND)); // 124 ms
060 * </code>
061 * 
062 * @param <Q>
063 *          The type of the quantity.
064 *
065 * @author <a href="mailto:martin.desruisseaux@geomatys.com">Martin Desruisseaux</a>
066 * @author <a href="mailto:units@catmedia.us">Werner Keil</a>
067 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
068 * @version 1.1, $Date: 2018-03-04 $
069 * @since 1.0
070 */
071public abstract class ProxyQuantityFactory<Q extends Quantity<Q>> implements QuantityFactory<Q> {
072
073  /**
074   * Holds the current instances.
075   */
076  @SuppressWarnings("rawtypes")
077  private static final Map<Class, ProxyQuantityFactory> INSTANCES = new ConcurrentHashMap<>();
078
079  private static final Logger logger = Logger.getLogger(ProxyQuantityFactory.class.getName());
080
081  private static final Level LOG_LEVEL = Level.FINE;
082
083  /**
084   * Returns the default instance for the specified quantity type.
085   *
086   * @param <Q>
087   *          The type of the quantity
088   * @param type
089   *          the quantity type
090   * @return the quantity factory for the specified type
091   */
092  @SuppressWarnings("unchecked")
093  public static <Q extends Quantity<Q>> ProxyQuantityFactory<Q> getInstance(final Class<Q> type) {
094
095    logger.log(LOG_LEVEL, "Type: " + type + ": " + type.isInterface());
096    ProxyQuantityFactory<Q> factory;
097    if (!type.isInterface()) {
098      if (type != null && type.getInterfaces() != null & type.getInterfaces().length > 0) {
099        logger.log(LOG_LEVEL, "Type0: " + type.getInterfaces()[0]);
100        Class<?> type2 = type.getInterfaces()[0];
101
102        factory = INSTANCES.get(type2);
103        if (factory != null)
104          return factory;
105        if (!AbstractQuantity.class.isAssignableFrom(type2))
106          // This exception is not documented because it should never happen if the
107          // user don't try to trick the Java generic types system with unsafe cast.
108          throw new ClassCastException();
109        factory = new Default<>((Class<Q>) type2);
110        INSTANCES.put(type2, factory);
111      } else {
112        factory = INSTANCES.get(type);
113        if (factory != null)
114          return factory;
115        if (!AbstractQuantity.class.isAssignableFrom(type))
116          // This exception is not documented because it should never happen if the
117          // user don't try to trick the Java generic types system with unsafe cast.
118          throw new ClassCastException();
119        factory = new Default<>(type);
120        INSTANCES.put(type, factory);
121      }
122    } else {
123      factory = INSTANCES.get(type);
124      if (factory != null)
125        return factory;
126      if (!Quantity.class.isAssignableFrom(type))
127        // This exception is not documented because it should never happen if the
128        // user don't try to trick the Java generic types system with unsafe cast.
129        throw new ClassCastException();
130      factory = new Default<>(type);
131      INSTANCES.put(type, factory);
132    }
133    return factory;
134  }
135
136  /**
137   * Overrides the default implementation of the factory for the specified quantity type.
138   *
139   * @param <Q>
140   *          The type of the quantity
141   * @param type
142   *          the quantity type
143   * @param factory
144   *          the quantity factory
145   */
146  protected static <Q extends Quantity<Q>> void setInstance(final Class<Q> type, ProxyQuantityFactory<Q> factory) {
147    if (!AbstractQuantity.class.isAssignableFrom(type))
148      // This exception is not documented because it should never happen if the
149      // user don't try to trick the Java generic types system with unsafe cast.
150      throw new ClassCastException();
151    INSTANCES.put(type, factory);
152  }
153
154  /**
155   * Returns the metric unit for quantities produced by this factory or <code>null</code> if unknown.
156   *
157   * @return the metric units for this factory quantities.
158   */
159  public abstract Unit<Q> getSystemUnit();
160
161  /**
162   * The default factory implementation. This factory uses reflection for providing a default implementation for every {@link AbstractMeasurement}
163   * sub-types.
164   *
165   * @param <Q>
166   *          The type of the quantity
167   */
168  private static final class Default<Q extends Quantity<Q>> extends ProxyQuantityFactory<Q> {
169
170    /**
171     * The type of the quantities created by this factory.
172     */
173    private final Class<Q> type;
174
175    /**
176     * The metric unit for quantities created by this factory.
177     */
178    private final Unit<Q> metricUnit;
179
180    /**
181     * Creates a new factory for quantities of the given type.
182     *
183     * @param type
184     *          The type of the quantities created by this factory.
185     */
186    @SuppressWarnings("unchecked")
187    Default(final Class<Q> type) {
188      this.type = type;
189      metricUnit = CLASS_TO_METRIC_UNIT.get(type);
190    }
191
192    @SuppressWarnings("rawtypes")
193    static final HashMap<Class, Unit> CLASS_TO_METRIC_UNIT = new HashMap<>();
194    static {
195      CLASS_TO_METRIC_UNIT.put(Dimensionless.class, AbstractUnit.ONE);
196      CLASS_TO_METRIC_UNIT.put(ElectricCurrent.class, AMPERE);
197      CLASS_TO_METRIC_UNIT.put(LuminousIntensity.class, CANDELA);
198      CLASS_TO_METRIC_UNIT.put(Temperature.class, KELVIN);
199      CLASS_TO_METRIC_UNIT.put(Mass.class, KILOGRAM);
200      CLASS_TO_METRIC_UNIT.put(Length.class, METRE);
201      CLASS_TO_METRIC_UNIT.put(AmountOfSubstance.class, MOLE);
202      CLASS_TO_METRIC_UNIT.put(Time.class, SECOND);
203      // CLASS_TO_METRIC_UNIT.put(MagnetomotiveForce.class, AMPERE_TURN);
204      CLASS_TO_METRIC_UNIT.put(Angle.class, RADIAN);
205      CLASS_TO_METRIC_UNIT.put(SolidAngle.class, STERADIAN);
206      // CLASS_TO_METRIC_UNIT.put(Information.class, BIT);
207      CLASS_TO_METRIC_UNIT.put(Frequency.class, HERTZ);
208      CLASS_TO_METRIC_UNIT.put(Force.class, NEWTON);
209      CLASS_TO_METRIC_UNIT.put(Pressure.class, PASCAL);
210      CLASS_TO_METRIC_UNIT.put(Energy.class, JOULE);
211      CLASS_TO_METRIC_UNIT.put(Power.class, WATT);
212      CLASS_TO_METRIC_UNIT.put(ElectricCharge.class, COULOMB);
213      CLASS_TO_METRIC_UNIT.put(ElectricPotential.class, VOLT);
214      CLASS_TO_METRIC_UNIT.put(ElectricCapacitance.class, FARAD);
215      CLASS_TO_METRIC_UNIT.put(ElectricResistance.class, OHM);
216      CLASS_TO_METRIC_UNIT.put(ElectricConductance.class, SIEMENS);
217      CLASS_TO_METRIC_UNIT.put(MagneticFlux.class, WEBER);
218      CLASS_TO_METRIC_UNIT.put(MagneticFluxDensity.class, TESLA);
219      CLASS_TO_METRIC_UNIT.put(ElectricInductance.class, HENRY);
220      CLASS_TO_METRIC_UNIT.put(LuminousFlux.class, LUMEN);
221      CLASS_TO_METRIC_UNIT.put(Illuminance.class, LUX);
222      CLASS_TO_METRIC_UNIT.put(Radioactivity.class, BECQUEREL);
223      CLASS_TO_METRIC_UNIT.put(RadiationDoseAbsorbed.class, GRAY);
224      CLASS_TO_METRIC_UNIT.put(RadiationDoseEffective.class, SIEVERT);
225      CLASS_TO_METRIC_UNIT.put(CatalyticActivity.class, KATAL);
226      CLASS_TO_METRIC_UNIT.put(Speed.class, METRE_PER_SECOND);
227      CLASS_TO_METRIC_UNIT.put(Acceleration.class, METRE_PER_SQUARE_SECOND);
228      CLASS_TO_METRIC_UNIT.put(Area.class, SQUARE_METRE);
229      CLASS_TO_METRIC_UNIT.put(Volume.class, CUBIC_METRE);
230    }
231
232    @Override
233    public Unit<Q> getSystemUnit() {
234      return metricUnit;
235    }
236
237    @SuppressWarnings("unchecked")
238    @Override
239    public Quantity<Q> create(Number value, Unit<Q> unit) {
240      // System.out.println("Type: " + type);
241      return (Q) Proxy.newProxyInstance(type.getClassLoader(), new Class<?>[] { type }, new GenericHandler<>(value, unit));
242    }
243  }
244
245  /**
246   * The method invocation handler for implementation backed by any kind of {@link Number}. This is a fall back used when no specialized handler is
247   * available for the number type.
248   */
249  private static final class GenericHandler<Q extends Quantity<Q>> implements InvocationHandler {
250    final Unit<Q> unit;
251    final Number value;
252
253    GenericHandler(final Number value, final Unit<Q> unit) {
254      this.unit = unit;
255      this.value = value;
256    }
257
258    @SuppressWarnings("unchecked")
259    @Override
260    public Object invoke(final Object proxy, final Method method, final Object[] args) {
261      final String name = method.getName();
262      switch (name) {
263        case "doubleValue": { // Most frequent.
264          final Unit<Q> toUnit = (Unit<Q>) args[0];
265          if ((toUnit == unit) || (toUnit.equals(unit)))
266            return value.doubleValue(); // Returns value directly.
267          return unit.getConverterTo(toUnit).convert(value.doubleValue());
268        }
269        case "longValue": {
270          final Unit<Q> toUnit = (Unit<Q>) args[0];
271          if ((toUnit == unit) || (toUnit.equals(unit)))
272            return value.longValue(); // Returns value directly.
273          double doubleValue = unit.getConverterTo(toUnit).convert(value.doubleValue());
274          if ((doubleValue < Long.MIN_VALUE) || (doubleValue > Long.MAX_VALUE))
275            throw new ArithmeticException("Overflow: " + doubleValue + " cannot be represented as a long");
276          return (long) doubleValue;
277        }
278        case "getValue":
279          return value;
280        case "getUnit":
281          return unit;
282        case "toString":
283          return String.valueOf(value) + ' ' + unit;
284        case "hashCode":
285          return value.hashCode() * 31 + unit.hashCode();
286        case "equals": {
287          final Object obj = args[0];
288          if (!(obj instanceof AbstractQuantity))
289            return false;
290          final AbstractQuantity<Q> that = (AbstractQuantity<Q>) obj;
291          return unit.isCompatible((AbstractUnit<?>) that.getUnit()) && value.doubleValue() == (that).doubleValue(unit);
292        }
293        case "compareTo": {
294          final AbstractQuantity<Q> that = (AbstractQuantity<Q>) args[0];
295          return Double.compare(value.doubleValue(), that.doubleValue(unit));
296        }
297        default:
298          throw new UnsupportedOperationException(name);
299      }
300    }
301  }
302}