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 * Defines mapping for composite foreign keys. This annotation
020 * groups <code>JoinColumn</code> annotations for the same relationship.
021 * <p>
022 * <p> When the <code>JoinColumns</code> annotation is used,
023 * both the <code>name</code> and the <code>referencedColumnName</code> elements
024 * must be specified in each such <code>JoinColumn</code> annotation.
025 * <p>
026 * <pre>
027 *
028 *    Example:
029 *    &#064;ManyToOne
030 *    &#064;JoinColumns({
031 *        &#064;JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
032 *        &#064;JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
033 *    })
034 *    public Address getAddress() { return address; }
035 * </pre>
036 *
037 * @see JoinColumn
038 * @since Java Persistence 1.0
039 */
040@Target({FIELD})
041@Retention(RUNTIME)
042public @interface JoinColumns {
043  JoinColumn[] value();
044
045  /**
046   * (Optional) The foreign key constraint specification for the join columns. This is used only if table
047   * generation is in effect.  Default is provider defined.
048   *
049   * @return The foreign key specification
050   */
051  ForeignKey foreignKey() default @ForeignKey();
052}