/*******************************************************************************
* 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.InternalWhenClauseBNF;
import org.eclipse.persistence.jpa.jpql.parser.ScalarExpressionBNF;
import org.eclipse.persistence.jpa.jpql.parser.WhenClause;
import org.eclipse.persistence.jpa.jpql.tools.model.Problem;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;
import static org.eclipse.persistence.jpa.jpql.parser.Expression.*;
/**
* A <code><b>WHEN</b></code> predicate is used to calculate a condition and when it's true, its
* <code><b>THEN</b></code> will be executed.
*
* <div><b>BNF:</b> <code>when_clause ::= WHEN conditional_expression THEN scalar_expression</code><p></div>
* or
* <div><b>BNF:</b> <code>simple_when_clause ::= WHEN scalar_expression THEN scalar_expression</code><p></div>
*
* @see org.eclipse.persistence.jpa.jpql.parser.WhenClause WhenClause
*
* @version 2.4
* @since 2.4
* @author Pascal Filion
*/
@SuppressWarnings({"nls", "unused"}) // unused used for the import statement: see bug 330740
public class WhenClauseStateObject extends AbstractConditionalClauseStateObject {
/**
* The {@link StateObject} representing the scalar expression that is following the
* <code><b>THEN</b></code> identifier.
*/
private StateObject thenStateObject;
/**
* Notify the {@link StateObject} representing the scalar expression that follows the
* <code><b>THEN</b></code> identifier has changed.
*/
public static final String THEN_STATE_OBJECT_PROPERTY = "thenStateObject";
/**
* Creates a new <code>WhenClauseStateObject</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 WhenClauseStateObject(CaseExpressionStateObject parent) {
super(parent);
}
/**
* Creates a new <code>WhenClauseStateObject</code>.
*
* @param parent The parent of this state object
* @param whenStateObject The {@link StateObject} representing the conditional expression that
* is following the <code><b>WHEN</b></code> identifier
* @param thenStateObject The {@link StateObject} representing the scalar expression that
* is following the <code><b>THEN</b></code> identifier
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public WhenClauseStateObject(CaseExpressionStateObject parent,
StateObject whenStateObject,
StateObject thenStateObject) {
super(parent, whenStateObject);
this.thenStateObject = parent(thenStateObject);
}
/**
* Creates a new <code>WhenClauseStateObject</code>.
*
* @param parent The parent of this state object
* @param whenJpqlFragment The string representation of the <code><b>WHEN</b></code> clause to
* parse and to convert into a {@link StateObject}
* @param thenJpqlFragment The string representation of the <code><b>THEN</b></code> expression
* to parse and to convert into a {@link StateObject}
* @exception NullPointerException The given parent cannot be <code>null</code>
*/
public WhenClauseStateObject(CaseExpressionStateObject parent,
String whenJpqlFragment,
String thenJpqlFragment) {
super(parent);
parseWhen(whenJpqlFragment);
parseThen(thenJpqlFragment);
}
/**
* {@inheritDoc}
*/
public void accept(StateObjectVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildren(List<StateObject> children) {
super.addChildren(children);
if (thenStateObject != null) {
children.add(thenStateObject);
}
}
/**
* {@inheritDoc}
*/
@Override
protected void addProblems(List<Problem> problems) {
super.addProblems(problems);
// if (!hasWhenStateObject()) {
// problems.add(buildProblem(StateObjectProblem.WhenClauseStateObject_MissingWhenStateObject));
// }
if (!hasThen()) {
problems.add(buildProblem(StateObjectProblem.WhenClauseStateObject_MissingThenStateObject));
}
}
/**
* {@inheritDoc}
*/
@Override
public WhenClause getExpression() {
return (WhenClause) super.getExpression();
}
/**
* {@inheritDoc}
*/
@Override
public String getIdentifier() {
return WHEN;
}
/**
* {@inheritDoc}
*/
@Override
public CaseExpressionStateObject getParent() {
return (CaseExpressionStateObject) super.getParent();
}
/**
* Returns the {@link StateObject} representing the scalar expression that is following the
* <code><b>THEN</b></code> identifier.
*
* @return Either the {@link StateObject} representing the <code><b>THEN</b></code> expression
* or <code>null</code> if it's not defined
*/
public StateObject getThen() {
return thenStateObject;
}
/**
* Determines whether the {@link StateObject} representing the scalar expression is present.
*
* @return <code>true</code> the scalar expression exists; otherwise <code>false</code>
*/
public boolean hasThen() {
return thenStateObject != null;
}
/**
* {@inheritDoc}
*/
@Override
public boolean isEquivalent(StateObject stateObject) {
if (super.isEquivalent(stateObject)) {
WhenClauseStateObject whenClause = (WhenClauseStateObject) stateObject;
return areEquivalent(thenStateObject, whenClause.thenStateObject);
}
return false;
}
/**
* Parses the given JPQL fragment, which will represent the <code><b>THEN</b></code> expression.
* The JPQL fragment should not start with the identifier.
*
* @param jpqlFragment The string representation of the <code><b>THEN</b></code> expression
* to parse and to convert into a {@link StateObject}
*/
public void parseThen(String jpqlFragment) {
StateObject stateObject = buildStateObject(jpqlFragment, ScalarExpressionBNF.ID);
setThen(stateObject);
}
/**
* Parses the given JPQL fragment, which will represent the <code><b>WHEN</b></code> clause.
* The JPQL fragment should not start with the identifier.
*
* @param jpqlFragment The string representation of the <code><b>WHEN</b></code> clause to
* parse and to convert into a {@link StateObject}
*/
public void parseWhen(String jpqlFragment) {
StateObject stateObject = buildStateObject(jpqlFragment, InternalWhenClauseBNF.ID);
setConditional(stateObject);
}
/**
* Keeps a reference of the {@link WhenClause 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 WhenClause parsed object} representing a <code><b>WHEN</b></code>
* clause
*/
public void setExpression(WhenClause expression) {
super.setExpression(expression);
}
/**
* Sets the scalar expression to be the given {@link StateObject}.
*
* @param thenStateObject The {@link StateObject} representing the scalar expression
*/
public void setThen(StateObject thenStateObject) {
StateObject oldThenStateObject = this.thenStateObject;
this.thenStateObject = parent(thenStateObject);
firePropertyChanged(THEN_STATE_OBJECT_PROPERTY, oldThenStateObject, thenStateObject);
}
/**
* {@inheritDoc}
*/
@Override
public void toTextInternal(Appendable writer) throws IOException {
super.toTextInternal(writer);
writer.append(SPACE);
// THEN scalar_expression
writer.append(THEN);
if (thenStateObject != null) {
writer.append(SPACE);
thenStateObject.toString(writer);
}
}
}