/*******************************************************************************
 * Copyright (c) 1998, 2009 Oracle. 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:
 *     dclarke - Java Persistence 2.0 - Proposed Final Draft (March 13, 2009)
 *     		     Specification available from http://jcp.org/en/jsr/detail?id=317
 *
 * Java(TM) Persistence API, Version 2.0 - EARLY ACCESS
 * This is an implementation of an early-draft specification developed under the 
 * Java Community Process (JCP).  The code is untested and presumed not to be a  
 * compatible implementation of JSR 317: Java(TM) Persistence API, Version 2.0.   
 * We encourage you to migrate to an implementation of the Java(TM) Persistence 
 * API, Version 2.0 Specification that has been tested and verified to be compatible 
 * as soon as such an implementation is available, and we encourage you to retain 
 * this notice in any implementation of Java(TM) Persistence API, Version 2.0 
 * Specification that you distribute.
 ******************************************************************************/
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.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * This annotation defines a primary key generator that may be 
 * referenced by name when a generator element is specified for 
 * the {@link GeneratedValue} annotation. A table generator 
 * may be specified on the entity class or on the primary key 
 * field or property. The scope of the generator name is global 
 * to the persistence unit (across all generator types).
 *
 * <pre>
 *    Example 1:
 *    
 *    &#064;Entity public class Employee {
 *        ...
 *        &#064;TableGenerator(
 *            name="empGen", 
 *            table="ID_GEN", 
 *            pkColumnName="GEN_KEY", 
 *            valueColumnName="GEN_VALUE", 
 *            pkColumnValue="EMP_ID", 
 *            allocationSize=1)
 *        &#064;Id
 *        &#064;GeneratedValue(strategy=TABLE, generator="empGen")
 *        public int id;
 *        ...
 *    }
 *    
 *    Example 2:
 *    
 *    &#064;Entity public class Address {
 *        ...
 *        &#064;TableGenerator(
 *            name="addressGen", 
 *            table="ID_GEN", 
 *            pkColumnName="GEN_KEY", 
 *            valueColumnName="GEN_VALUE", 
 *            pkColumnValue="ADDR_ID")
 *        &#064;Id
 *        &#064;GeneratedValue(strategy=TABLE, generator="addressGen")
 *        public int id;
 *        ...
 *    }
 * </pre>
 *
 * @since Java Persistence 1.0
 */
@Target({TYPE, METHOD, FIELD}) 
@Retention(RUNTIME)
public @interface TableGenerator {

    /** 
     * (Required) A unique generator name that can be referenced 
     * by one or more classes to be the generator for id values.
     */
    String name();

    /** 
     * (Optional) Name of table that stores the generated id values. 
     * <p> Defaults to a name chosen by persistence provider.
     */
    String table() default "";

    /** (Optional) The catalog of the table. 
     * <p> Defaults to the default catalog.
     */
    String catalog() default "";

    /** (Optional) The schema of the table. 
     * <p> Defaults to the default schema for user.
     */
    String schema() default "";

    /** 
     * (Optional) Name of the primary key column in the table.
     * <p> Defaults to a provider-chosen name.
     */
    String pkColumnName() default "";

    /** 
     * (Optional) Name of the column that stores the last value generated.
     * <p> Defaults to a provider-chosen name.
     */
    String valueColumnName() default "";

    /**
     * (Optional) The primary key value in the generator table 
     * that distinguishes this set of generated values from others 
     * that may be stored in the table.
     * <p> Defaults to a provider-chosen value to store in the 
     * primary key column of the generator table
     */
    String pkColumnValue() default "";

    /** 
     * (Optional) The initial value to be used when allocating id 
     * numbers from the generator. 
     */
    int initialValue() default 0;

    /**
     * (Optional) The amount to increment by when allocating id 
     * numbers from the generator.
     */
    int allocationSize() default 50;

    /**
     * (Optional) Unique constraints that are to be placed on the 
     * table. These are only used if table generation is in effect. 
     * These constraints apply in addition to primary key constraints.
     * <p> Defaults to no additional constraints.
     */
    UniqueConstraint[] uniqueConstraints() default {};
}