/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.isis.applib.annotation;
/**
* Whether the property or parameter is optional or is required (aka mandatory).
*/
public enum Optionality {
/**
* Default, usually meaning mandatory for properties and always meaning mandatory for parameters.
*
* <p>
* For properties, will be false unless JDO {@link javax.jdo.annotations.Column} has also specified with
* {@link javax.jdo.annotations.Column#allowsNull()} set to <code>true</code>.
* </p>
*/
DEFAULT,
/**
* Indicates that the property or parameter is not required.
*/
OPTIONAL,
/**
* Indicates that the property is required (even if the JDO {@link javax.jdo.annotations.Column} annotation
* says otherwise).
*
* <p>
* When using the JDO/DataNucleus objectstore, it is sometimes necessary to annotate a property as optional
* (using {@link javax.jdo.annotations.Column#allowsNull()} set to <code>true</code>), even if the property is
* logically mandatory. For example, this can occur when the property is in a subtype class that has been
* "rolled up" to the superclass table using {@link javax.jdo.annotations.Inheritance} with the
* {@link javax.jdo.annotations.InheritanceStrategy#SUPERCLASS_TABLE superclass}<tt> strategy.
* </p>
*
* <p>
* This annotation, therefore, is intended to override any objectstore-specific
* annotation, so that Isis can apply the constraint even though the objectstore
* is unable to do so.
* </p>
*/
MANDATORY
}