/******************************************************************************* | |
* Copyright (c) 2008, 2009 Sun Microsystems. 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. | |
* | |
* Contributors: | |
* Linda DeMichiel -Java Persistence 2.0 - Proposed Final Draft, Version 2.0 (August 31, 2009) | |
* Specification available from http://jcp.org/en/jsr/detail?id=317 | |
******************************************************************************/ | |
package javax.persistence; | |
import java.lang.annotation.Target; | |
import java.lang.annotation.Retention; | |
import static java.lang.annotation.ElementType.FIELD; | |
import static java.lang.annotation.ElementType.METHOD; | |
import static java.lang.annotation.RetentionPolicy.RUNTIME; | |
/** | |
* Designates a <code>ManyToOne</code> or | |
* <code>OneToOne</code> relationship attribute that provides the | |
* mapping for an {@link EmbeddedId} primary key, an attribute within | |
* an <code>EmbeddedId</code> primary key, or a simple primary key of | |
* the parent entity. The <code>value</code> element specifies the | |
* attribute within a composite key to which the relationship | |
* attribute corresponds. If the entity's primary key is of the same | |
* Java type as the primary key of the entity referenced by the | |
* relationship, the value attribute is not specified. | |
* | |
* <pre> | |
* Example: | |
* | |
* // parent entity has simple primary key | |
* | |
* @Entity | |
* public class Employee { | |
* @Id long empId; | |
* String name; | |
* ... | |
* } | |
* | |
* // dependent entity uses EmbeddedId for composite key | |
* | |
* @Embeddable | |
* public class DependentId { | |
* String name; | |
* long empid; // corresponds to primary key type of Employee | |
* } | |
* | |
* @Entity | |
* public class Dependent { | |
* @EmbeddedId DependentId id; | |
* ... | |
* @MapsId("empid") // maps the empid attribute of embedded id | |
* @ManyToOne Employee emp; | |
* } | |
* </pre> | |
* | |
* @since Java Persistence 2.0 | |
*/ | |
@Target( { METHOD, FIELD }) | |
@Retention(RUNTIME) | |
public @interface MapsId { | |
/** | |
* (Optional) The name of the attribute within the composite key | |
* to which the relationship attribute corresponds. If not | |
* supplied, the relationship maps the entity's primary | |
* key. | |
*/ | |
String value() default ""; } |