/*
 * 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.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

Defines mapping for composite foreign keys. This annotation
groups JoinColumn annotations for the same relationship.

 When the JoinColumns annotation is used,
both the name and the referencedColumnName elements
must be specified in each such JoinColumn annotation.

   Example:
   @ManyToOne
   @JoinColumns({
       @JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
       @JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
   })
   public Address getAddress() { return address; }

See Also:
JoinColumn
Since:
Java Persistence 1.0/**
 * Defines mapping for composite foreign keys. This annotation
 * groups <code>JoinColumn</code> annotations for the same relationship.
 * <p>
 * <p> When the <code>JoinColumns</code> annotation is used,
 * both the <code>name</code> and the <code>referencedColumnName</code> elements
 * must be specified in each such <code>JoinColumn</code> annotation.
 * <p>
 * <pre>
 *
 *    Example:
 *    &#064;ManyToOne
 *    &#064;JoinColumns({
 *        &#064;JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
 *        &#064;JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
 *    })
 *    public Address getAddress() { return address; }
 * </pre>
 *
 * @see JoinColumn
 * @since Java Persistence 1.0
 */
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface JoinColumns {
  JoinColumn[] 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();
}