How to use

getClassExtractionMethodName

method

in

org.eclipse.persistence.descriptors.MethodClassExtractor

/**
 * ADVANCED:
 * A class extraction method can be registered with the descriptor to override the default inheritance mechanism.
 * This allows for a user defined class indicator in place of providing an explicit class indicator field.
 * The method registered must be a static method on the class which has that descriptor. The method must take a
 * Record as an argument (for example, a DatabaseRecord), and must return the class to use for that record.
 * This method will be used to decide which class to instantiate when reading from the database.
 * It is the application's responsibility to populate any typing information in the database required
 * to determine the class from the record.
 * If this method is used, then the class indicator field and mapping cannot be used, and in addition,
 * the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly.
 *
 * @see #setWithAllSubclassesExpression(Expression)
 * @see #setOnlyInstancesExpression(Expression)
 */
public String getClassExtractionMethodName() {
  if (classExtractor instanceof MethodClassExtractor) {
    return ((MethodClassExtractor)classExtractor).getClassExtractionMethodName();
  } else {
    return null;
  }
}

/**
 * ADVANCED:
 * A class extraction method can be registered with the descriptor to override the default inheritance mechanism.
 * This allows for a user defined class indicator in place of providing an explicit class indicator field.
 * The method registered must be a static method on the class which has that descriptor. The method must take a 
 * Record as an argument (for example, a DatabaseRecord), and must return the class to use for that record. 
 * This method will be used to decide which class to instantiate when reading from the database. 
 * It is the application's responsibility to populate any typing information in the database required
 * to determine the class from the record. 
 * If this method is used, then the class indicator field and mapping cannot be used, and in addition, 
 * the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly.
 *
 * @see #setWithAllSubclassesExpression(Expression)
 * @see #setOnlyInstancesExpression(Expression)
 */
public String getClassExtractionMethodName() {
  if (classExtractor instanceof MethodClassExtractor) {
    return ((MethodClassExtractor)classExtractor).getClassExtractionMethodName();
  } else {
    return null;
  }
}

/**
 * ADVANCED:
 * A class extraction method can be registered with the descriptor to override the default inheritance mechanism.
 * This allows for a user defined class indicator in place of providing an explicit class indicator field.
 * The method registered must be a static method on the class which has that descriptor. The method must take a 
 * Record as an argument (for example, a DatabaseRecord), and must return the class to use for that record. 
 * This method will be used to decide which class to instantiate when reading from the database. 
 * It is the application's responsibility to populate any typing information in the database required
 * to determine the class from the record. 
 * If this method is used, then the class indicator field and mapping cannot be used, and in addition, 
 * the descriptor's withAllSubclasses and onlyInstances expressions must also be setup correctly.
 *
 * @see #setWithAllSubclassesExpression(Expression)
 * @see #setOnlyInstancesExpression(Expression)
 */
public String getClassExtractionMethodName() {
  if (classExtractor instanceof MethodClassExtractor) {
    return ((MethodClassExtractor)classExtractor).getClassExtractionMethodName();
  } else {
    return null;
  }
}

/**
 * INTERNAL:
 * Setup the default classExtractionMethod, or if one was specified by the user make sure it is valid.
 */
public void initialize(ClassDescriptor descriptor, Session session) throws DescriptorException {
  setDescriptor(descriptor);
  Class[] declarationParameters = new Class[1];
  declarationParameters[0] = ClassConstants.DatabaseRow_Class;
  try {
    setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters));
  } catch (NoSuchMethodException ignore) {
    declarationParameters[0] = ClassConstants.Record_Class;
    try {
      setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters));
    } catch (NoSuchMethodException exception) {
      throw DescriptorException.noSuchMethodWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
    } catch (SecurityException exception) {
      throw DescriptorException.securityWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
    }
  } catch (SecurityException exception) {
    throw DescriptorException.securityWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
  }
  // CR#2818667 Ensure the method is static.
  if (!Modifier.isStatic(getClassExtractionMethod().getModifiers())) {
    throw DescriptorException.classExtractionMethodMustBeStatic(getClassExtractionMethodName(), descriptor);
  }
}

/**
 * INTERNAL:
 * Setup the default classExtractionMethod, or if one was specified by the user make sure it is valid.
 */
public void initialize(ClassDescriptor descriptor, Session session) throws DescriptorException {
  setDescriptor(descriptor);
  Class[] declarationParameters = new Class[1];
  declarationParameters[0] = ClassConstants.DatabaseRow_Class;
  try {
    setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters));
  } catch (NoSuchMethodException ignore) {
    declarationParameters[0] = ClassConstants.Record_Class;
    try {
      setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters));
    } catch (NoSuchMethodException exception) {
      throw DescriptorException.noSuchMethodWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
    } catch (SecurityException exception) {
      throw DescriptorException.securityWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
    }
  } catch (SecurityException exception) {
    throw DescriptorException.securityWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
  }
  // CR#2818667 Ensure the method is static.
  if (!Modifier.isStatic(getClassExtractionMethod().getModifiers())) {
    throw DescriptorException.classExtractionMethodMustBeStatic(getClassExtractionMethodName(), descriptor);
  }
}

/**
 * INTERNAL:
 * Setup the default classExtractionMethod, or if one was specified by the user make sure it is valid.
 */
public void initialize(ClassDescriptor descriptor, Session session) throws DescriptorException {
  setDescriptor(descriptor);
  Class[] declarationParameters = new Class[1];
  declarationParameters[0] = ClassConstants.DatabaseRow_Class;
  try {
    setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters));
  } catch (NoSuchMethodException ignore) {
    declarationParameters[0] = ClassConstants.Record_Class;
    try {
      setClassExtractionMethod(Helper.getDeclaredMethod(descriptor.getJavaClass(), getClassExtractionMethodName(), declarationParameters));
    } catch (NoSuchMethodException exception) {
      throw DescriptorException.noSuchMethodWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
    }
  } catch (SecurityException exception) {
    throw DescriptorException.securityWhileInitializingClassExtractionMethod(getClassExtractionMethodName(), descriptor, exception);
  }
  // CR#2818667 Ensure the method is static.
  if (!Modifier.isStatic(getClassExtractionMethod().getModifiers())) {
    throw DescriptorException.classExtractionMethodMustBeStatic(getClassExtractionMethodName(), descriptor);
  }
}