/*******************************************************************************
* 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 java.util.List;
import org.eclipse.persistence.jpa.jpql.parser.EmptyCollectionComparisonExpression;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;
import static org.eclipse.persistence.jpa.jpql.parser.Expression.*;
/**
* This expression tests whether or not the collection designated by the collection-valued path
* expression is empty (i.e, has no elements).
*
* <div><b>BNF:</b> <code>empty_collection_comparison_expression ::= collection_valued_path_expression IS [NOT] EMPTY</code><p></div>
*
* @see EmptyCollectionComparisonExpression
*
* @version 2.4
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings({"nls", "unused"}) // unused used for the import statement: see bug 330740
public class EmptyCollectionComparisonExpressionStateObject extends AbstractStateObject {
/**
* Determines whether the <code><b>NOT</b></code> identifier is part of the expression or not.
*/
private boolean not;
/**
* The {@link StateObject} representing the collection-valued path expression.
*/
private CollectionValuedPathExpressionStateObject stateObject;
/**
* Notifies the visibility of the <code><b>NOT</b></code> identifier has changed.
*/
public static final String NOT_PROPERTY = "not";
/**
* Creates a new <code>EmptyCollectionComparisonExpressionStateObject</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>
*/
public EmptyCollectionComparisonExpressionStateObject(StateObject parent) {
super(parent);
}
/**
* Creates a new <code>EmptyCollectionComparisonExpressionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param not Determines whether the <code><b>NOT</b></code> identifier is part of the expression
* or not
* @param path The collection-valued path expression
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public EmptyCollectionComparisonExpressionStateObject(StateObject parent,
boolean not,
String path) {
super(parent);
this.not = not;
this.stateObject.setPath(path);
}
/**
* Creates a new <code>EmptyCollectionComparisonExpressionStateObject</code>.
*
* @param parent The parent of this state object, which cannot be <code>null</code>
* @param path The collection-valued path expression
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public EmptyCollectionComparisonExpressionStateObject(StateObject parent, String path) {
this(parent, false, path);
}
/**
* {@inheritDoc}
*/
public void accept(StateObjectVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildren(List<StateObject> children) {
super.addChildren(children);
children.add(stateObject);
}
/**
* Makes sure the <code><b>NOT</b></code> identifier is specified.
*
* @return This object
*/
public EmptyCollectionComparisonExpressionStateObject addNot() {
if (!not) {
setNot(true);
}
return this;
}
/**
* {@inheritDoc}
*/
@Override
public EmptyCollectionComparisonExpression getExpression() {
return (EmptyCollectionComparisonExpression) super.getExpression();
}
/**
* Returns the {@link CollectionValuedPathExpressionStateObject} representing the collection-
* valued path expression.
*
* @return The {@link CollectionValuedPathExpressionStateObject} representing the collection-
* valued path expression, which is never <code>null</code>
*/
public CollectionValuedPathExpressionStateObject getStateObject() {
return stateObject;
}
/**
* Determines whether the <code><b>NOT</b></code> identifier is used or not.
*
* @return <code>true</code> if the <code><b>NOT</b></code> identifier is part of the expression;
* <code>false</code> otherwise
*/
public boolean hasNot() {
return not;
}
/**
* {@inheritDoc}
*/
@Override
protected void initialize() {
super.initialize();
stateObject = new CollectionValuedPathExpressionStateObject(this);
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEquivalent(StateObject stateObject) {
if (super.isEquivalent(stateObject)) {
EmptyCollectionComparisonExpressionStateObject collection = (EmptyCollectionComparisonExpressionStateObject) stateObject;
return not == collection.not &&
stateObject.isEquivalent(collection.stateObject);
}
return false;
}
/**
* Makes sure the <code><b>NOT</b></code> identifier is not specified.
*/
public void removeNot() {
if (not) {
setNot(false);
}
}
/**
* Keeps a reference of the {@link EmptyCollectionComparisonExpression parsed object} object,
* which should only be done when this object is instantiated during the conversion of a parsed
* JPQL query into {@link StateObject StateObjects}.
*
* @param expression The {@link EmptyCollectionComparisonExpression parsed object} representing
* an <code><b>EMPTY</b></code> expression
*/
public void setExpression(EmptyCollectionComparisonExpression expression) {
super.setExpression(expression);
}
/**
* Sets whether the <code><b>NOT</b></code> identifier should be part of the expression or not.
*
* @param not <code>true</code> if the <code><b>NOT</b></code> identifier should be part of the
* expression; <code>false</code> otherwise
*/
public void setNot(boolean not) {
boolean oldNot = this.not;
this.not = not;
firePropertyChanged(NOT_PROPERTY, oldNot, not);
}
/**
* Changes the visibility state of the <code><b>NOT</b></code> identifier.
*/
public void toggleNot() {
setNot(!not);
}
/**
* {@inheritDoc}
*/
@Override
protected void toTextInternal(Appendable writer) throws IOException {
stateObject.toString(writer);
writer.append(SPACE);
if (not) {
writer.append(IS_NOT_EMPTY);
}
else {
writer.append(IS_EMPTY);
}
}
}