com.github.drinkjava2.jdialects.annotation.jpa.GeneratedValue Maven / Gradle / Ivy

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/*
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later. See
 * the lgpl.txt file in the root directory or
 * .
 */
package com.github.drinkjava2.jdialects.annotation.jpa;

import static com.github.drinkjava2.jdialects.annotation.jpa.GenerationType.AUTO;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * Provides for the specification of generation strategies for the
 * values of primary keys. 
 *
 *  The GeneratedValue 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 GeneratedValue annotation is only
 * required to be supported for simple primary keys.  Use of the
 * GeneratedValue annotation is not supported for derived
 * primary keys.
 *
 * 
 *
 *     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;
 * 
 *
 * @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.
     *  Defaults to the id generator supplied by persistence provider.
     */
    String generator() default "";
}