/*******************************************************************************
 * Copyright (c) 2008 - 2012 Oracle Corporation. 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.
 *
 * Contributors:
 *     Linda DeMichiel - Java Persistence 2.1
 *     Linda DeMichiel - Java Persistence 2.0
 *
 ******************************************************************************/ 
package javax.persistence;

import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Groups {@link PrimaryKeyJoinColumn} annotations.
 * It is used to map composite foreign keys.
 *
 * <pre>
 *    Example: ValuedCustomer subclass
 *
 *    &#064;Entity
 *    &#064;Table(name="VCUST")
 *    &#064;DiscriminatorValue("VCUST")
 *    &#064;PrimaryKeyJoinColumns({
 *        &#064;PrimaryKeyJoinColumn(name="CUST_ID", 
 *            referencedColumnName="ID"),
 *        &#064;PrimaryKeyJoinColumn(name="CUST_TYPE",
 *            referencedColumnName="TYPE")
 *    })
 *    public class ValuedCustomer extends Customer { ... }
 * </pre>
 *
 * @see ForeignKey
 *
 * @since Java Persistence 1.0
 */
@Target({TYPE, METHOD, FIELD})
@Retention(RUNTIME)

public @interface PrimaryKeyJoinColumns {

    /** One or more <code>PrimaryKeyJoinColumn</code> annotations. */
    PrimaryKeyJoinColumn[] value();

    /**
     *  (Optional)  Used to specify or disable a foreign key constraint when
     *  table generation is in effect.  If this element is not specified,
     *  the persistence provider's default foreign key strategy will apply.
     *
     *  @since Java Persistence 2.1
     */
    ForeignKey foreignKey() default @ForeignKey();

}