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

/*
 * Copyright (c) 2011, 2021 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.IEntity;
import org.eclipse.persistence.jpa.jpql.tools.spi.IManagedType;

/**
 * Range variable declarations allow the developer to designate a "root" for objects which may not
 * be reachable by navigation. In order to select values by comparing more than one instance of an
 * entity abstract schema type, more than one identification variable ranging over the abstract
 * schema type is needed in the <code><b>FROM</b></code> clause.
 *
 * <div><p><b>BNF:</b> <code>range_variable_declaration ::= abstract_schema_name [AS] identification_variable</code></p></div>
 *
 * @see org.eclipse.persistence.jpa.jpql.parser.RangeVariableDeclaration RangeVariableDeclaration
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
public class RangeVariableDeclarationStateObject extends AbstractRangeVariableDeclarationStateObject {

    /**
     * Creates a new <code>RangeVariableDeclarationStateObject</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 RangeVariableDeclarationStateObject(AbstractModifyClauseStateObject parent) {
        super(parent);
        setIdentificationVariableOptional(true);
    }

    /**
     * Creates a new <code>RangeVariableDeclarationStateObject</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 RangeVariableDeclarationStateObject(IdentificationVariableDeclarationStateObject parent) {
        super(parent);
    }

    /**
     * Creates a new <code>RangeVariableDeclarationStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param entityName The name of the abstract schema, which is the name of the entity
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public RangeVariableDeclarationStateObject(IdentificationVariableDeclarationStateObject parent,
                                               String entityName) {

        super(parent, entityName);
    }

    @Override
    public void accept(StateObjectVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    public RangeVariableDeclarationStateObject addAs() {
        return (RangeVariableDeclarationStateObject) super.addAs();
    }

    @Override
    protected StateObject buildRootStateObject() {
        return new AbstractSchemaNameStateObject(this);
    }

    /**
     * Returns the actual {@link IEntity} that has the abstract schema name.
     *
     * @return The actual {@link IEntity} or <code>null</code> if no entity exists
     */
    public IEntity getEntity() {
        return getRootStateObject().getEntity();
    }

    /**
     * Returns the abstract schema name.
     *
     * @return The name of the abstract schema type for which the identification variable is ranging over
     */
    public String getEntityName() {
        return getRootStateObject().getText();
    }

    @Override
    public IManagedType getManagedType(StateObject stateObject) {

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

        return null;
    }

    @Override
    public String getRootPath() {
        return getEntityName();
    }

    @Override
    public AbstractSchemaNameStateObject getRootStateObject() {
        return (AbstractSchemaNameStateObject) super.getRootStateObject();
    }

    /**
     * Sets the abstract schema name to the given value.
     *
     * @param entity The {@link IEntity} that this clause will range over
     */
    public void setDeclaration(IEntity entity) {
        setEntity(entity);
        setIdentificationVariable(null);
    }

    /**
     * Sets the abstract schema name to the given value and the identification variable that will
     * range over it.
     *
     * @param entity The {@link IEntity} that this clause will range over
     * @param identificationVariable The new identification variable
     */
    public void setDeclaration(IEntity entity, String identificationVariable) {
        setEntity(entity);
        setIdentificationVariable(identificationVariable);
    }

    /**
     * Sets the abstract schema name to the given value and the identification variable that will
     * range over it.
     *
     * @param entityName The name of the entity name
     * @param identificationVariable The new identification variable
     */
    public void setDeclaration(String entityName, String identificationVariable) {
        setEntityName(entityName);
        setIdentificationVariable(identificationVariable);
    }

    /**
     * Sets the actual {@link IEntity} and updates the abstract schema name.
     *
     * @param entity The {@link IEntity} that the clause will range over
     */
    public void setEntity(IEntity entity) {
        getRootStateObject().setEntity(entity);
    }

    /**
     * Sets the name of the abstract schema, which is the name of the entity.
     *
     * @param abstractSchemaName The name of the abstract schema, which is the name of the entity
     */
    public void setEntityName(String abstractSchemaName) {
        getRootStateObject().setText(abstractSchemaName);
    }

    @Override
    public void setRootPath(String root) {
        setEntityName(root);
    }
}