SubExpressionStateObject.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.Assert;
import org.eclipse.persistence.jpa.jpql.ExpressionTools;
import org.eclipse.persistence.jpa.jpql.parser.SubExpression;

/**
 * This expression wraps a sub-expression within parenthesis.
 *
 * <div><b>BNF:</b> <code>expression ::= (sub_expression)</code><p></div>
 *
 * @see SubExpression
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
@SuppressWarnings("nls")
public class SubExpressionStateObject extends AbstractSingleEncapsulatedExpressionStateObject {

    /**
     * The unique identifier of the {@link org.eclipse.persistence.jpa.jpql.parser.JPQLQueryBNF
     * JPQLQueryBNF} that is used to parse the encapsulated expression.
     */
    private String queryBNFId;

    /**
     * Creates a new <code>SubExpressionStateObject</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 SubExpressionStateObject(StateObject parent) {
        super(parent);
    }

    /**
     * Creates a new <code>SubExpressionStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param stateObject The {@link StateObject} representing the encapsulated expression
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public SubExpressionStateObject(StateObject parent, StateObject stateObject) {
        super(parent, stateObject);
    }

    /**
     * Creates a new <code>SubExpressionStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @param jpqlFragment The portion of the query representing the encapsulated expression
     * @param queryBNFId  The unique identifier of the {@link org.eclipse.persistence.jpa.jpql.parser
     * .JPQLQueryBNF JPQLQueryBNF} that is used to parse the encapsulated expression
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    public SubExpressionStateObject(StateObject parent, String jpqlFragment, String queryBNFId) {
        super(parent);
        this.queryBNFId = queryBNFId;
        parse(jpqlFragment);
    }

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

    /**
     * {@inheritDoc}
     */
    @Override
    public SubExpression getExpression() {
        return (SubExpression) super.getExpression();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getIdentifier() {
        return ExpressionTools.EMPTY_STRING;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected String getQueryBNFId() {
        return queryBNFId;
    }

    /**
     * Keeps a reference of the {@link SubExpression parsed object} object, which should only be
     * done when this object is instantiated during the conversion of a parsed JPQL query into
     * {@link StateObject StateObjects}.
     *
     * @param expression The {@link SubExpression parsed object} representing an encapsulated
     * expression
     */
    public void setExpression(SubExpression expression) {
        super.setExpression(expression);
    }

    /**
     * Sets the unique identifier of the {@link org.eclipse.persistence.jpa.jpql.parser.JPQLQueryBNF
     * JPQLQueryBNF} that is used to parse the encapsulated expression.
     *
     * @param queryBNFId The non-<code>null</code> ID of the BNF
     * @exception NullPointerException The query BNF ID cannot be <code>null</code>
     */
    public void setQueryBNFId(String queryBNFId) {
        Assert.isNotNull(queryBNFId, "The query BNF ID cannot be null");
        this.queryBNFId = queryBNFId;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setStateObject(StateObject stateObject) {
        super.setStateObject(stateObject);
    }
}