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/*
 * Copyright (c) 2006, 2018 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.parser;

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

/**
 * The AND logical operator chains multiple criteria together. A valid operand of an
 * AND operator must be one of: TRUE, FALSE, and NULL. The
 * AND operator has a higher precedence than the OR operator.
 * 
 * NULL represents unknown. Therefore, if one operand is NULL and the other operand
 * is FALSE the result is FALSE, because one FALSE operand is sufficient for
 * a FALSE result. If one operand is NULL and the other operand is either
 * TRUE or NULL, the result is NULL (unknown).
 * 

 * The following table shows how the AND operator is evaluated based on its two operands:
 *
 * 
 * 
 * 
 * 
 * 
 *             TRUE FALSE NULL
TRUE    TRUE       FALSE       NULL    
FALSE    FALSE      FALSE       FALSE   
NULL    NULL       FALSE       NULL    
 *
 * BNF: conditional_term ::= conditional_term AND conditional_factor
 *
 * @version 2.5
 * @since 2.3
 * @author Pascal Filion
 */
public final class AndExpression extends LogicalExpression {

    /**
     * Creates a new AndExpression.
     *
     * @param parent The parent of this expression
     */
    public AndExpression(AbstractExpression parent) {
        super(parent, AND);
    }

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

    /**
     * {@inheritDoc}
     */
    @Override
    public String getLeftExpressionQueryBNFId() {
        return ConditionalTermBNF.ID;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getRightExpressionQueryBNFId() {
        return ConditionalFactorBNF.ID;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
        return word.equalsIgnoreCase(AND) ||
               word.equalsIgnoreCase(OR)  ||
               super.isParsingComplete(wordParser, word, expression);
    }
}

	TRUE	FALSE	NULL
TRUE	TRUE	FALSE	NULL
FALSE	FALSE	FALSE	FALSE
NULL	NULL	FALSE	NULL