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

Supports composite map keys that reference entities.

The MapKeyJoinColumns annotation groups MapKeyJoinColumn annotations. When the
MapKeyJoinColumns annotation is used, both the name and the
referencedColumnName elements must be specified in each of the grouped
MapKeyJoinColumn annotations.
See Also:
MapKeyJoinColumn
Since:
Java Persistence 2.0/**
 * Supports composite map keys that reference entities.
 * <p>
 * The <code>MapKeyJoinColumns</code> annotation groups <code>MapKeyJoinColumn</code> annotations. When the
 * <code>MapKeyJoinColumns</code> annotation is used, both the <code>name</code> and the
 * <code>referencedColumnName</code> elements must be specified in each of the grouped
 * <code>MapKeyJoinColumn</code> annotations.
 *
 * @see MapKeyJoinColumn
 * @since Java Persistence 2.0
 */
@Target({FIELD})
@Retention(RUNTIME)
public @interface MapKeyJoinColumns {
  
(Required) The map key join columns that are used to map to the entity that is the map key.
Returns:
The join cols/**
   * (Required) The map key join columns that are used to map to the entity that is the map key.
   *
   * @return The join cols
   */
  MapKeyJoinColumn[] value();

  
(Optional) The foreign key constraint specification for the join columns. This is used only if table
generation is in effect. Default is provider defined.
Returns:
The foreign key specification/**
   * (Optional) The foreign key constraint specification for the join columns. This is used only if table
   * generation is in effect. Default is provider defined.
   *
   * @return The foreign key specification
   */
  ForeignKey foreignKey() default @ForeignKey();
}