com.raynigon.unit_api.jpa.annotation.JpaUnitHelper Maven / Gradle / Ivy

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package com.raynigon.unit_api.jpa.annotation;

import com.raynigon.unit_api.core.annotation.QuantityShape;
import com.raynigon.unit_api.core.units.general.IUnit;

import javax.measure.Quantity;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

/** Support a simple usage of the @JpaUnit properties */
public class JpaUnitHelper {

  /**
   * Determine the value of the shape property
   *
   * @param jpaUnit the annotation which should be processed
   * @return the specified Shape or QuantityShape.NUMBER if no shape was specified
   */
  public static QuantityShape getShape(JpaUnit jpaUnit) {
    if (jpaUnit == null) return QuantityShape.NUMBER;
    return jpaUnit.shape();
  }

  /**
   * Determine the value of the unit property
   *
   * @param jpaUnit the annotation which should be processed
   * @return the name of the specified unit or null if no unit was specified
   */
  public static IUnit getUnitInstance(JpaUnit jpaUnit) {
    if (jpaUnit == null) return null;
    if (!jpaUnit.value().equals(JpaUnit.NoneUnit.class)) return createUnit(jpaUnit.value());
    if (!jpaUnit.unit().equals(JpaUnit.NoneUnit.class)) return createUnit(jpaUnit.unit());
    return null;
  }

  /**
   * Determine the value of the unit property
   *
   * @param jpaUnit the annotation which should be processed
   * @return the name of the specified unit or null if no unit was specified
   */
  public static Class> getQuantityType(JpaUnit jpaUnit) {
    if (jpaUnit == null) return null;
    Class> quantityType = jpaUnit.quantityType();
    if (quantityType.equals(NoneQuantity.class)) return null;
    if (!Quantity.class.isAssignableFrom(quantityType)) return null;
    return quantityType;
  }

  private static IUnit createUnit(Class> unitType) {
    try {
      Constructor> ctor = unitType.getConstructor();
      return ctor.newInstance();
    } catch (NoSuchMethodException | InstantiationException | IllegalAccessException | InvocationTargetException e) {
      // TODO log error("Unable to create Unit " + unitType, e);
      return null;
    }
  }
}