DerivedPathVariableDeclarationStateObject.java

/*******************************************************************************
 * Copyright (c) 2011, 2015 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 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:
 *     Oracle - initial API and implementation
 *
 ******************************************************************************/
package org.eclipse.persistence.jpa.jpql.tools.model.query;

import org.eclipse.persistence.jpa.jpql.tools.spi.IManagedType;

/**
 * <div><b>BNF:</b> <code>subselect_identification_variable_declaration ::= derived_path_expression [AS] identification_variable {join}*</code><p></div>
 *
 * <div><b>BNF:</b> <code>derived_path_expression ::= superquery_identification_variable.{single_valued_object_field.}*collection_valued_field |
 *                                                           superquery_identification_variable.{single_valued_object_field.}*single_valued_object_field</code><p></div>
 *
 * @see org.eclipse.persistence.jpa.jpql.parser.RangeVariableDeclaration RangeVariableDeclaration
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
public class DerivedPathVariableDeclarationStateObject extends AbstractRangeVariableDeclarationStateObject {

    /**
     * Creates a new <code>DerivedPathVariableDeclarationStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public DerivedPathVariableDeclarationStateObject(DerivedPathIdentificationVariableDeclarationStateObject parent) {
        super(parent);
    }

    /**
     * Creates a new <code>DerivedPathVariableDeclarationStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param path Either the derived singled-valued object path expression or the collection-valued
     * path expression
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public DerivedPathVariableDeclarationStateObject(DerivedPathIdentificationVariableDeclarationStateObject parent,
                                                     String path) {

        super(parent, path);
    }

    /**
     * {@inheritDoc}
     */
    public void accept(StateObjectVisitor visitor) {
        visitor.visit(this);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected StateObject buildRootStateObject() {
        return new CollectionValuedPathExpressionStateObject(this);
    }

    /**
     * {@inheritDoc}
     */
    public IManagedType getManagedType(StateObject stateObject) {

        if (getIdentificationVariableStateObject().isEquivalent(stateObject)) {
            return getRootStateObject().getManagedType();
        }

        return null;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public DerivedPathIdentificationVariableDeclarationStateObject getParent() {
        return (DerivedPathIdentificationVariableDeclarationStateObject) super.getParent();
    }

    /**
     * Returns the string representation of the path expression. If the identification variable is
     * virtual, then it is not part of the result.
     *
     * @return The path expression, which is never <code>null</code>
     */
    public String getPath() {
        return getRootStateObject().getPath();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getRootPath() {
        return getPath();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public CollectionValuedPathExpressionStateObject getRootStateObject() {
        return (CollectionValuedPathExpressionStateObject) super.getRootStateObject();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setRootPath(String path) {
        getRootStateObject().setPath(path);
    }
}