org.hibernate.annotations.Any Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.annotations;
import java.lang.annotation.Retention;
import javax.persistence.Column;
import javax.persistence.FetchType;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Defines a ToOne-style association pointing to one of several entity types depending on a local discriminator,
* as opposed to discriminated inheritance where the discriminator is kept as part of the entity hierarchy.
*
* For example, if you consider an Order entity containing Payment information where Payment might be of type
* CashPayment or CreditCardPayment the @Any approach would be to keep that discriminator and matching value on the
* Order itself. Thought of another way, the "foreign-key" really is made up of the value and discriminator
* (there is no physical foreign key here as databases do not support this):
*
* @Entity
* class Order {
* ...
* @Any( metaColumn = @Column( name="payment_type" ) )
* @AnyMetDef(
* idType = "long"
* metaValues = {
* @MetaValue( value="C", targetEntity=CashPayment.class ),
* @MetaValue( value="CC", targetEntity=CreditCardPayment.class ),
* }
* )
* pubic Payment getPayment() { ... }
* }
* }
*
*
* @author Emmanuel Bernard
* @author Steve Ebersole
*
* @see AnyMetaDef
*/
@java.lang.annotation.Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface Any {
/**
* Metadata definition used.
* If defined, should point to a @AnyMetaDef name
* If not defined, the local (ie in the same field or property) @AnyMetaDef is used
*/
String metaDef() default "";
/**
* Identifies the discriminator column. This column will hold the value that identifies the targeted entity.
*/
Column metaColumn();
/**
* Defines whether the value of the field or property should be lazily loaded or must be
* eagerly fetched. The EAGER strategy is a requirement on the persistence provider runtime
* that the value must be eagerly fetched. The LAZY strategy is applied when bytecode
* enhancement is used. If not specified, defaults to EAGER.
*/
FetchType fetch() default FetchType.EAGER;
/**
* Whether the association is optional. If set to false then a non-null relationship must always exist.
*/
boolean optional() default true;
}