jpa/org.eclipse.persistence.jpa.jpql/src/main/java/org/eclipse/persistence/jpa/jpql/tools/model/query/VariableDeclarationStateObject.java

/*
 * Copyright (c) 2011, 2020 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:
//     Oracle - initial API and implementation
//
package org.eclipse.persistence.jpa.jpql.tools.model.query;

import org.eclipse.persistence.jpa.jpql.tools.spi.IManagedType;
import org.eclipse.persistence.jpa.jpql.utility.iterable.ListIterable;

/**
 * This defines a variable declaration, which has a "root" object and an identification variable.
 *
 * @see CollectionMemberDeclarationStateObject
 * @see DerivedPathIdentificationVariableDeclarationStateObject
 * @see DerivedPathVariableDeclarationStateObject
 * @see IdentificationVariableDeclarationStateObject
 * @see RangeVariableDeclarationStateObject
 *
 * @version 2.5
 * @since 2.4
 * @author Pascal Filion
 */
public interface VariableDeclarationStateObject extends StateObject {

    /**
     * Returns the {@link IManagedType} for the given identification variable. The search does not
     * traverse up the query hierarchy if this declaration is for a subquery.
     *
     * <pre><code>SELECT e FROM Department d JOIN KEY(d.employees).addresses a</code></pre>
     * In the above query, the managed type associated with the identification variable:
     * <ul>
     * <li>d is "Department"
     * <li>a is "Address"
     * </ul>
     *
     * @param stateObject The {@link StateObject} that should be an simple identification variable or
     * an encapsulated identification variable with the identifier <code><b>KEY</b></code> or
     * <code><b>VALUE</b></code>
     * @return The {@link IManagedType} representing the domain object declared by the given
     * identification variable
     */
    IManagedType getManagedType(StateObject stateObject);

    /**
     * Returns the {@link IdentificationVariableStateObject} that are used by this state object. It
     * is possible more than one declaration exists, like a range variable declaration has also joins
     * and join fetches.
     *
     * @return The list of {@link IdentificationVariableStateObject}
     */
    ListIterable<IdentificationVariableStateObject> identificationVariables();
}