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/*
 * Copyright (c) 2008, 2023 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Linda DeMichiel - 2.1
//     Linda DeMichiel - 2.0

package jakarta.persistence.criteria;

import jakarta.persistence.metamodel.Attribute;

/**
 * A join to an entity, embeddable, or basic type.
 *
 * @param  the source type of the join
 * @param  the target type of the join
 *
 * @since 2.0
 */
public interface Join extends From {

    /**
     * Modify the join to restrict the result according to the
     * specified ON condition and return the join object.  
     * Replaces the previous ON condition, if any.
     * @param restriction  a simple or compound boolean expression
     * @return the modified join object
     * @since 2.1
     */
    Join on(Expression restriction);

    /**
     * Modify the join to restrict the result according to the
     * specified ON condition and return the join object.  
     * Replaces the previous ON condition, if any.
     * @param restrictions  zero or more restriction predicates
     * @return the modified join object
     * @since 2.1
     */
    Join on(Predicate... restrictions);

    /** 
     * Return the predicate that corresponds to the ON 
     * restriction(s) on the join, or null if no ON condition 
     * has been specified.
     * @return the ON restriction predicate
     * @since 2.1
     */
    Predicate getOn();

    /**
     * Return the metamodel attribute representing the join
     * target, if any, or null if the target of the join is an
     * entity type.
     * @return metamodel attribute or null
     */
    Attribute getAttribute();

    /**
     * Return the parent of the join.
     * @return join parent
     */
    From getParent();

    /**
     * Return the join type.
     * @return join type
     */
    JoinType getJoinType();
}