javax.persistence.AssociationOverride Maven / Gradle / Ivy
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/*
* Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution. The Eclipse Public License is available
* at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
* is available at http://www.eclipse.org/org/documents/edl-v10.php.
*/
package javax.persistence;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Repeatable;
/**
* Used to override a mapping for an entity relationship.
*
* May be applied to an entity that extends a mapped superclass to override a relationship mapping defined by
* the mapped superclass. If not specified, the association is mapped the same as in the original mapping.
* When used to override a mapping defined by a mapped superclass, AssociationOverride is applied
* to the entity class.
*
* May be used to override a relationship mapping from an embeddable within an entity to another entity when
* the embeddable is on the owning side of the relationship. When used to override a relationship mapping
* defined by an embeddable class (including an embeddable class embedded within another embeddable class),
* AssociationOverride is applied to the field or property containing the embeddable.
*
* When AssociationOverride is used to override a relationship mapping from an embeddable class,
* the name element specifies the referencing relationship field or property within the
* embeddable class. To override mappings at multiple levels of embedding, a dot (".") notation syntax must be
* used in the name element to indicate an attribute within an embedded attribute. The value of
* each identifier used with the dot notation is the name of the respective embedded field or property.
*
* When AssociationOverride is applied to override the mappings of an embeddable class used as a
* map value, "value." must be used to prefix the name of the attribute within the embeddable
* class that is being overridden in order to specify it as part of the map value.
*
* If the relationship mapping is a foreign key mapping, the joinColumns element is used. If the
* relationship mapping uses a join table, the joinTable element must be specified to override
* the mapping of the join table and/or its join columns.
*
* Example 1: Overriding the mapping of a relationship defined by a mapped superclass
*
* @MappedSuperclass
* public class Employee {
* ...
* @ManyToOne
* protected Address address;
* ...
* }
*
* @Entity
* @AssociationOverride(name="address",
* joinColumns=@JoinColumn(name="ADDR_ID"))
* // address field mapping overridden to ADDR_ID foreign key
* public class PartTimeEmployee extends Employee {
* ...
* }
*
*
*
* Example 2: Overriding the mapping for phoneNumbers defined in the ContactInfo class
*
* @Entity
* public class Employee {
* @Id int id;
* @AssociationOverride(
* name="phoneNumbers",
* joinTable=@JoinTable(
* name="EMPPHONES",
* joinColumns=@JoinColumn(name="EMP"),
* inverseJoinColumns=@JoinColumn(name="PHONE")
* )
* )
* @Embedded ContactInfo contactInfo;
* ...
* }
*
* @Embeddable
* public class ContactInfo {
* @ManyToOne Address address; // Unidirectional
* @ManyToMany(targetEntity=PhoneNumber.class) List phoneNumbers;
* }
*
* @Entity
* public class PhoneNumber {
* @Id int number;
* @ManyToMany(mappedBy="contactInfo.phoneNumbers")
* Collection<Employee> employees;
* }
*
* @see Embedded
* @see Embeddable
* @see MappedSuperclass
* @see AttributeOverride
* @since Java Persistence 1.0
*/
@Target({TYPE, METHOD, FIELD})
@Retention(RUNTIME)
@Repeatable(AssociationOverrides.class)
public @interface AssociationOverride
{
/**
* (Required) The name of the relationship property whose mapping is being overridden if property-based
* access is being used, or the name of the relationship field if field-based access is used.
* @return name
*/
String name();
/**
* The join column(s) being mapped to the persistent attribute(s). The joinColumns elements
* must be specified if a foreign key mapping is used in the overriding of the mapping of the
* relationship. The joinColumns element must not be specified if a join table is used in the
* overriding of the mapping of the relationship.
* @return join cols
*/
JoinColumn[] joinColumns() default {};
/**
* The join table that maps the relationship. The joinTable element must be specified if a
* join table is used in the overriding of the mapping of the relationship. The joinTable
* element must not be specified if a foreign key mapping is used in the overriding of the relationship.
* @since Java Persistence 2.0
* @return join table
*/
JoinTable joinTable() default @JoinTable;
/**
* (Optional) Used to specify or control the generation of a foreign key constraint for the columns
* corresponding to the joinColumns element when table generation is in effect.
* @since Java Persistence 2.1
* @return FK
*/
ForeignKey foreignKey() default @ForeignKey(ConstraintMode.PROVIDER_DEFAULT);
}