/*******************************************************************************
* 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 java.io.IOException;
import org.eclipse.persistence.jpa.jpql.parser.AggregateFunction;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;
import static org.eclipse.persistence.jpa.jpql.parser.Expression.*;
/**
* In the <code><b>SELECT</b></code> clause the result of a query may be the result of an aggregate
* function applied to a path expression.
*
* <pre><code>BNF: aggregate_expression ::= {AVG|MAX|MIN|SUM}([DISTINCT] state_field_path_expression) |
* COUNT([DISTINCT] identification_variable | state_field_path_expression | single_valued_association_path_expression)</code></pre>
*
* @see org.eclipse.persistence.jpa.jpql.parser.AggregateFunction AggregateFunction
*
* @version 2.4
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings({"nls", "unused"}) // unused used for the import statement: see bug 330740
public abstract class AggregateFunctionStateObject extends AbstractSingleEncapsulatedExpressionStateObject {
/**
* Determines whether the <code><b>DISTINCT</b></code> keyword is part of the query, which is
* used to return only distinct (different) values.
*/
private boolean distinct;
/**
* Notifies the visibility of the <code><b>DISTINCT</b></code> identifier has changed.
*/
public static final String DISTINCT_PROPERTY = "distinct";
/**
* Creates a new <code>AggregateFunctionStateObject</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>
*/
protected AggregateFunctionStateObject(StateObject parent) {
super(parent);
}
/**
* Creates a new <code>AggregateStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param distinct <code>true</code> to add <code><b>DISTINCT</b></code> to the query in order to
* have distinct values; <code>false</code> if it is not required
* @param stateObject The {@link StateObject} representing the encapsulated expression
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
protected AggregateFunctionStateObject(StateObject parent,
boolean distinct,
StateObject stateObject) {
super(parent, stateObject);
this.distinct = distinct;
}
/**
* Creates a new <code>AggregateFunctionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param distinct <code>true</code> to add <code><b>DISTINCT</b></code> to the query in order to
* have distinct values; <code>false</code> if it is not required
* @param path Either the identification variable or the state field path expression
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
protected AggregateFunctionStateObject(StateObject parent, boolean distinct, String path) {
super(parent, path);
this.distinct = distinct;
}
/**
* Creates a new <code>AggregateStateObject</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>
*/
protected AggregateFunctionStateObject(StateObject parent, StateObject stateObject) {
this(parent, false, stateObject);
}
/**
* Creates a new <code>AggregateFunctionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param path Either the identification variable or the state field path expression
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
protected AggregateFunctionStateObject(StateObject parent, String path) {
super(parent, path);
}
/**
* {@inheritDoc}
*/
@Override
public AggregateFunction getExpression() {
return (AggregateFunction) super.getExpression();
}
/**
* Sets whether the <code><b>DISTINCT</b></code> keyword should be part of the query, which is
* used to return only distinct (different) values.
*
* @return <code>true</code> to add <code><b>DISTINCT</b></code> to the query in order to have
* distinct values; <code>false</code> if it is not required
*/
public boolean hasDistinct() {
return distinct;
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEquivalent(StateObject stateObject) {
if (super.isEquivalent(stateObject)) {
AggregateFunctionStateObject function = (AggregateFunctionStateObject) stateObject;
return distinct == function.distinct;
}
return false;
}
/**
* Sets whether the <code><b>DISTINCT</b></code> keyword should be part of the query, which is
* used to return only distinct (different) values
*
* @param distinct <code>true</code> to add <code><b>DISTINCT</b></code> to the query in order to
* have distinct values; <code>false</code> if it is not required
*/
public void setDistinct(boolean distinct) {
boolean oldDistinct = this.distinct;
this.distinct = distinct;
firePropertyChanged(DISTINCT_PROPERTY, oldDistinct, distinct);
}
/**
* {@inheritDoc}
*/
@Override
public void setStateObject(StateObject stateObject) {
super.setStateObject(stateObject);
}
/**
* Reverses the visibility of the <code><b>DISTINCT</b></code> identifier.
*/
public void toggleDistinct() {
setDistinct(!hasDistinct());
}
/**
* {@inheritDoc}
*/
@Override
protected void toTextEncapsulatedExpression(Appendable writer) throws IOException {
if (hasDistinct()) {
writer.append(DISTINCT);
writer.append(SPACE);
}
super.toTextEncapsulatedExpression(writer);
}
}