001/*
002 * Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
003 *
004 * This program and the accompanying materials are made available under the
005 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
006 * which accompanies this distribution.  The Eclipse Public License is available
007 * at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
008 * is available at http://www.eclipse.org/org/documents/edl-v10.php.
009 */
010package javax.persistence;
011
012import java.lang.annotation.Retention;
013import java.lang.annotation.Target;
014
015import static java.lang.annotation.ElementType.FIELD;
016import static java.lang.annotation.RetentionPolicy.RUNTIME;
017
018/**
019 * Supports composite map keys that reference entities.
020 * <p>
021 * The <code>MapKeyJoinColumns</code> annotation groups <code>MapKeyJoinColumn</code> annotations. When the
022 * <code>MapKeyJoinColumns</code> annotation is used, both the <code>name</code> and the
023 * <code>referencedColumnName</code> elements must be specified in each of the grouped
024 * <code>MapKeyJoinColumn</code> annotations.
025 *
026 * @see MapKeyJoinColumn
027 * @since Java Persistence 2.0
028 */
029@Target({FIELD})
030@Retention(RUNTIME)
031public @interface MapKeyJoinColumns {
032  /**
033   * (Required) The map key join columns that are used to map to the entity that is the map key.
034   *
035   * @return The join cols
036   */
037  MapKeyJoinColumn[] value();
038
039  /**
040   * (Optional) The foreign key constraint specification for the join columns. This is used only if table
041   * generation is in effect. Default is provider defined.
042   *
043   * @return The foreign key specification
044   */
045  ForeignKey foreignKey() default @ForeignKey();
046}