KeywordExpressionFactory.java

/*******************************************************************************
 * Copyright (c) 2006, 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.parser;

import org.eclipse.persistence.jpa.jpql.WordParser;

/**
 * This <code>KeywordExpressionFactory</code> creates a new {@link KeywordExpression} when the
 * portion of the JPQL query to parse is <code><b>FALSE</b></code>, <code><b>TRUE</b></code> or
 * <code><b>NULL</b></code>.
 * <p>
 * EclipseLink 2.5 added two new identifiers: <code><b>MINVALUE</b></code> and <code><b>MAXVALUE</b></code>.
 *
 * @see KeywordExpression
 *
 * @version 2.5
 * @since 2.3
 * @author Pascal Filion
 */
@SuppressWarnings("nls")
public final class KeywordExpressionFactory extends ExpressionFactory {

    /**
     * The unique identifier of this {@link KeywordExpressionFactory}.
     */
    public static final String ID = "keyword";

    /**
     * Creates a new <code>KeywordExpressionFactory</code>.
     */
    public KeywordExpressionFactory() {
        super(ID, Expression.FALSE,
                  Expression.NULL,
                  Expression.TRUE);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected AbstractExpression buildExpression(AbstractExpression parent,
                                                 WordParser wordParser,
                                                 String word,
                                                 JPQLQueryBNF queryBNF,
                                                 AbstractExpression expression,
                                                 boolean tolerant) {

        for (String identifier : identifiers()) {
            if (identifier.equalsIgnoreCase(word)) {
                expression = new KeywordExpression(parent, identifier);
                expression.parse(wordParser, tolerant);
                return expression;
            }
        }

        return null;
    }
}