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/*******************************************************************************
* Copyright (c) 2006, 2013 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;
import static org.eclipse.persistence.jpa.jpql.parser.Expression.*;
/**
* This {@link IsExpressionFactory} creates a new expression when the portion of the query to parse
* starts with IS.
*
* @see EmptyCollectionComparisonExpression
* @see NullComparisonExpression
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
public final class IsExpressionFactory extends ExpressionFactory {
/**
* The unique identifier of this {@link IsExpressionFactory}.
*/
public static final String ID = IS;
/**
* Creates a new IsExpressionFactory
.
*/
public IsExpressionFactory() {
super(ID, IS,
IS_EMPTY,
IS_NOT_EMPTY,
IS_NOT_NULL,
IS_NULL);
}
/**
* {@inheritDoc}
*/
@Override
protected AbstractExpression buildExpression(AbstractExpression parent,
WordParser wordParser,
String word,
JPQLQueryBNF queryBNF,
AbstractExpression expression,
boolean tolerant) {
int position = wordParser.position();
int index = position + 2;
int count = wordParser.whitespaceCount(index);
index += count;
// IS NOT EMPTY or IS NOT NULL
if (wordParser.startsWithIdentifier(NOT, index)) {
index += 3;
count = wordParser.whitespaceCount(index);
index += count;
// IS NOT EMPTY
if (wordParser.startsWithIdentifier(EMPTY, index)) {
expression = new EmptyCollectionComparisonExpression(parent, IS_NOT_EMPTY, expression);
}
// IS NOT NULL
else if (wordParser.startsWithIdentifier(NULL, index)) {
expression = new NullComparisonExpression(parent, IS_NOT_NULL, expression);
}
// IS NOT
else {
word = wordParser.substring(position, index - count);
expression = new UnknownExpression(parent, word);
}
}
// IS EMPTY
else if (wordParser.startsWithIdentifier(EMPTY, index)) {
expression = new EmptyCollectionComparisonExpression(parent, IS_EMPTY, expression);
}
// IS NULL
else if (wordParser.startsWithIdentifier(NULL, index)) {
expression = new NullComparisonExpression(parent, IS_NULL, expression);
}
// IS
else {
word = wordParser.substring(position, index - count);
expression = new UnknownExpression(parent, word);
}
expression.parse(wordParser, tolerant);
return expression;
}
}