Java tutorial
/******************************************************************************* * Copyright (c) 2008 - 2013 Oracle Corporation. 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 2.1 * Linda DeMichiel - Java Persistence 2.0 * ******************************************************************************/ 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; import static javax.persistence.GenerationType.AUTO; /** * Provides for the specification of generation strategies for the * values of primary keys. * * <p> The <code>GeneratedValue</code> annotation * may be applied to a primary key property or field of an entity or * mapped superclass in conjunction with the {@link Id} annotation. * The use of the <code>GeneratedValue</code> annotation is only * required to be supported for simple primary keys. Use of the * <code>GeneratedValue</code> annotation is not supported for derived * primary keys. * * <pre> * * Example 1: * * @Id * @GeneratedValue(strategy=SEQUENCE, generator="CUST_SEQ") * @Column(name="CUST_ID") * public Long getId() { return id; } * * Example 2: * * @Id * @GeneratedValue(strategy=TABLE, generator="CUST_GEN") * @Column(name="CUST_ID") * Long id; * </pre> * * @see Id * @see TableGenerator * @see SequenceGenerator * * @since Java Persistence 1.0 */ @Target({ METHOD, FIELD }) @Retention(RUNTIME) public @interface GeneratedValue { /** * (Optional) The primary key generation strategy * that the persistence provider must use to * generate the annotated entity primary key. */ GenerationType strategy() default AUTO; /** * (Optional) The name of the primary key generator * to use as specified in the {@link SequenceGenerator} * or {@link TableGenerator} annotation. * <p> Defaults to the id generator supplied by persistence provider. */ String generator() default ""; }