src/javax/persistence/criteria/MapJoin.java

/*******************************************************************************
 * Copyright (c) 2008, 2009 Sun Microsystems. 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 2.0 - Proposed Final Draft, Version 2.0 (August 31, 2009)
 *     Specification available from http://jcp.org/en/jsr/detail?id=317
 *
 * Java(TM) Persistence API, Version 2.0 - EARLY ACCESS
 * This is an implementation of an early-draft specification developed under the 
 * Java Community Process (JCP).  The code is untested and presumed not to be a  
 * compatible implementation of JSR 317: Java(TM) Persistence API, Version 2.0.   
 * We encourage you to migrate to an implementation of the Java(TM) Persistence 
 * API, Version 2.0 Specification that has been tested and verified to be compatible 
 * as soon as such an implementation is available, and we encourage you to retain 
 * this notice in any implementation of Java(TM) Persistence API, Version 2.0 
 * Specification that you distribute.
 ******************************************************************************/
package javax.persistence.criteria;

import java.util.Map;
import javax.persistence.metamodel.MapAttribute;

/**
 * The <code>MapJoin</code> interface is the type of the result of
 * joining to a collection over an association or element 
 * collection that has been specified as a <code>java.util.Map</code>.
 *
 * @param <Z> the source type of the join
 * @param <K> the type of the target Map key
 * @param <V> the type of the target Map value
 *
 * @since Java Persistence 2.0
 */
public interface MapJoin<Z, K, V> 
		extends PluralJoin<Z, Map<K, V>, V> {

    /**
     * Return the metamodel representation for the map attribute.
     * @return metamodel type representing the <code>Map</code> that is
     *         the target of the join
     */
    MapAttribute<? super Z, K, V> getModel();
    
    /**
     * Create a path expression that corresponds to the map key.
     * @return path corresponding to map key
     */
    Path<K> key();
    
    /**
     * Create a path expression that corresponds to the map value.
     * This method is for stylistic use only: it just returns this.
     * @return path corresponding to the map value
     */
    Path<V> value(); 
    
    /**
     * Create an expression that corresponds to the map entry.
     * @return expression corresponding to the map entry
     */
    Expression<Map.Entry<K, V>> entry();
}