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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.*;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * 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).
 * 
 * 
 *    Example 1:
 *
 *    @Entity public class Employee {
 *        ...
 *        @TableGenerator(
 *            name="empGen",
 *            table="ID_GEN",
 *            pkColumnName="GEN_KEY",
 *            valueColumnName="GEN_VALUE",
 *            pkColumnValue="EMP_ID",
 *            allocationSize=1)
 *        @Id
 *        @GeneratedValue(strategy=TABLE, generator="empGen")
 *        int id;
 *        ...
 *    }
 *
 *    Example 2:
 *
 *    @Entity public class Address {
 *        ...
 *        @TableGenerator(
 *            name="addressGen",
 *            table="ID_GEN",
 *            pkColumnName="GEN_KEY",
 *            valueColumnName="GEN_VALUE",
 *            pkColumnValue="ADDR_ID")
 *        @Id
 *        @GeneratedValue(strategy=TABLE, generator="addressGen")
 *        int id;
 *        ...
 *    }
 * 
 *
 * @see GeneratedValue
 * @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.
   *
   * @return name
   */
  String name();

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

  /**
   * (Optional) The catalog of the table. Defaults to the default catalog.
   *
   * @return catalog
   */
  String catalog() default "";

  /**
   * (Optional) The schema of the table. Defaults to the default schema for user.
   *
   * @return schema
   */
  String schema() default "";

  /**
   * (Optional) Name of the primary key column in the table. Defaults to a provider-chosen name.
   *
   * @return pk col name
   */
  String pkColumnName() default "";

  /**
   * (Optional) Name of the column that stores the last value generated. Defaults to a provider-chosen name.
   *
   * @return value column 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. Defaults to a provider-chosen value to store in the
   * primary key column of the generator table
   *
   * @return pk col val
   */
  String pkColumnValue() default "";

  /**
   * (Optional) The initial value to be used to initialize the column that stores the last value generated.
   *
   * @return init val
   */
  int initialValue() default 0;

  /**
   * (Optional) The amount to increment by when allocating id numbers from the generator.
   *
   * @return alloc size
   */
  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. Defaults to no
   * additional constraints.
   *
   * @return unique constraints
   */
  UniqueConstraint[] uniqueConstraints() default {};

  /**
   * (Optional) Indexes for the table. These are only used if table generation is in effect.
   *
   * @return The indexes
   */
  Index[] indexes() default {};
}