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/*******************************************************************************
* Copyright (c) 2006, 2014 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;
/**
* One of the aggregate functions. The return type of this function is a Long
.
*
* BNF: expression ::= COUNT ([DISTINCT] identification_variable |
* state_field_path_expression |
* single_valued_object_path_expression)
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
public final class CountFunction extends AggregateFunction {
/**
* Creates a new CountFunction
.
*
* @param parent The parent of this expression
*/
public CountFunction(AbstractExpression parent) {
super(parent, COUNT);
}
/**
* {@inheritDoc}
*/
public void accept(ExpressionVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
@Override
protected AbstractExpression buildEncapsulatedExpression(WordParser wordParser, String word) {
if (KEY.equalsIgnoreCase(word)) {
ExpressionFactory factory = getExpressionFactory(KeyExpressionFactory.ID);
return factory.buildExpression(this, wordParser, word, getQueryBNF(), null, false);
}
if (VALUE.equalsIgnoreCase(word)) {
ExpressionFactory factory = getExpressionFactory(ValueExpressionFactory.ID);
return factory.buildExpression(this, wordParser, word, getQueryBNF(), null, false);
}
if (word.indexOf(DOT) == -1) {
return new IdentificationVariable(this, word);
}
return super.buildEncapsulatedExpression(wordParser, word);
}
/**
* {@inheritDoc}
*/
@Override
public String getEncapsulatedExpressionQueryBNFId() {
return InternalCountBNF.ID;
}
}