/*******************************************************************************
* Copyright (c) 2006, 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.parser;
import java.util.Collection;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.ExpressionTools;
import org.eclipse.persistence.jpa.jpql.WordParser;
/**
* Returns an expression that allows to treat its base as if it were a subclass of the class
* returned by the base.
* <p>
* New to EclipseLink 2.1.
*
* <div><b>BNF:</b> <code>join_treat ::= TREAT(collection_valued_path_expression AS entity_type_literal)</code></div>
* <p>
* Example: <code>SELECT e FROM Employee e JOIN TREAT(e.projects AS LargeProject) lp WHERE lp.budget = value</code>
*
* @version 2.5.1
* @since 2.3
* @author Pascal Filion
*/
public final class TreatExpression extends AbstractEncapsulatedExpression {
/**
* The actual <b>AS</b> identifier found in the string representation of the JPQL query.
*/
private String asIdentifier;
/**
* The {@link Expression} that represents the collection-valued path expression.
*/
private AbstractExpression collectionValuedPathExpression;
/**
* The entity type used to downcast the type of the elements in the collection.
*/
private AbstractExpression entityType;
/**
* Determines whether a whitespace was parsed after <b>AS</b>.
*/
private boolean hasSpaceAfterAs;
/**
* Determines whether a whitespace was parsed after the collection-valued path expression.
*/
private boolean hasSpaceAfterCollectionValuedPathExpression;
/**
* Determines which child expression is been currently parsed.
*/
private int parameterIndex;
/**
* Creates a new <code>TreatExpression</code>.
*
* @param parent The parent of this expression
*/
public TreatExpression(AbstractExpression parent) {
super(parent, TREAT);
}
/**
* {@inheritDoc}
*/
public void accept(ExpressionVisitor visitor) {
acceptUnknownVisitor(visitor);
}
/**
* {@inheritDoc}
*/
public void acceptChildren(ExpressionVisitor visitor) {
getCollectionValuedPathExpression().accept(visitor);
getEntityType().accept(visitor);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildrenTo(Collection<Expression> children) {
children.add(getCollectionValuedPathExpression());
children.add(getEntityType());
}
/**
* {@inheritDoc}
*/
@Override
protected void addOrderedEncapsulatedExpressionTo(List<Expression> children) {
// Collection-valued path expression
if (collectionValuedPathExpression != null) {
children.add(collectionValuedPathExpression);
}
if (hasSpaceAfterCollectionValuedPathExpression) {
children.add(buildStringExpression(SPACE));
}
// AS
if (asIdentifier != null) {
children.add(buildStringExpression(AS));
}
if (hasSpaceAfterAs) {
children.add(buildStringExpression(SPACE));
}
// Entity type
if (entityType != null) {
children.add(entityType);
}
}
/**
* {@inheritDoc}
*/
@Override
public final JPQLQueryBNF findQueryBNF(Expression expression) {
if ((collectionValuedPathExpression != null) && collectionValuedPathExpression.isAncestor(expression)) {
return getQueryBNF(CollectionValuedPathExpressionBNF.ID);
}
if ((entityType != null) && entityType.isAncestor(expression)) {
return getQueryBNF(EntityTypeLiteralBNF.ID);
}
return super.findQueryBNF(expression);
}
/**
* Returns the actual <b>AS</b> identifier found in the string representation of the JPQL
* query, which has the actual case that was used.
*
* @return The <b>AS</b> identifier that was actually parsed, or an empty string if it was not
* parsed
*/
public String getActualAsIdentifier() {
return (asIdentifier != null) ? asIdentifier : ExpressionTools.EMPTY_STRING;
}
/**
* Returns the {@link Expression} that represents the collection-valued path expression.
*
* @return The expression that represents the collection-valued path expression
*/
public Expression getCollectionValuedPathExpression() {
if (collectionValuedPathExpression == null) {
collectionValuedPathExpression = buildNullExpression();
}
return collectionValuedPathExpression;
}
/**
* Returns the {@link Expression} that represents the entity type that will be used to downcast
* the type of the elements in the collection.
*
* @return The expression representing the entity type
*/
public Expression getEntityType() {
if (entityType == null) {
entityType = buildNullExpression();
}
return entityType;
}
/**
* {@inheritDoc}
*/
public JPQLQueryBNF getQueryBNF() {
return getQueryBNF(TreatExpressionBNF.ID);
}
/**
* Determines whether the identifier <b>AS</b> was parsed.
*
* @return <code>true</code> if the identifier <b>AS</b> was parsed; <code>false</code> otherwise
*/
public boolean hasAs() {
return asIdentifier != null;
}
/**
* Determines whether the collection-valued path expression of the query was parsed.
*
* @return <code>true</code> if the collection-valued path expression was parsed;
* <code>false</code> if nothing was parsed
*/
public boolean hasCollectionValuedPathExpression() {
return collectionValuedPathExpression != null &&
!collectionValuedPathExpression.isNull();
}
/**
* {@inheritDoc}
*/
@Override
public boolean hasEncapsulatedExpression() {
return hasCollectionValuedPathExpression() || hasAs() || hasEntityType();
}
/**
* Determines whether the entity type was parsed.
*
* @return <code>true</code> if the entity type was parsed; <code>false</code> if nothing was
* parsed
*/
public boolean hasEntityType() {
return entityType != null &&
!entityType.isNull();
}
/**
* Determines whether a whitespace was parsed after <b>AS</b>.
*
* @return <code>true</code> if there was a whitespace after <b>AS</b>; <code>false</code>
* otherwise
*/
public boolean hasSpaceAfterAs() {
return hasSpaceAfterAs;
}
/**
* Determines whether a whitespace was parsed after the collection-valued path expression.
*
* @return <code>true</code> if a whitespace was parsed after the collection-valued path
* expression; <code>false</code> otherwise
*/
public boolean hasSpaceAfterCollectionValuedPathExpression() {
return hasSpaceAfterCollectionValuedPathExpression;
}
/**
* {@inheritDoc}
*/
@Override
protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
char character = wordParser.character();
// When parsing an invalid JPQL query (eg: LOCATE + ABS(e.name)) then "+ ABS(e.name)"
// should not be parsed as an invalid first expression
if ((parameterIndex == 0) &&
((character == '+') || (character == '-')) &&
!hasLeftParenthesis()) {
parameterIndex = -1;
return true;
}
return super.isParsingComplete(wordParser, word, expression);
}
/**
* {@inheritDoc}
*/
@Override
protected void parseEncapsulatedExpression(WordParser wordParser,
int whitespaceCount,
boolean tolerant) {
parameterIndex = 0;
// Collection-valued path expression
collectionValuedPathExpression = parse(
wordParser,
CollectionValuedPathExpressionBNF.ID,
tolerant
);
// See comment in isParsingComplete()
if (parameterIndex == -1) {
return;
}
hasSpaceAfterCollectionValuedPathExpression = wordParser.skipLeadingWhitespace() > 0;
// Parse 'AS'
if (wordParser.startsWithIdentifier(AS)) {
asIdentifier = wordParser.moveForward(AS);
hasSpaceAfterAs = wordParser.skipLeadingWhitespace() > 0;
}
parameterIndex = 1;
// Entity type
if (tolerant) {
entityType = parse(wordParser, EntityTypeLiteralBNF.ID, tolerant);
}
else {
entityType = new EntityTypeLiteral(this, wordParser.word());
entityType.parse(wordParser, tolerant);
}
}
/**
* {@inheritDoc}
*/
@Override
protected void removeEncapsulatedExpression() {
entityType = null;
asIdentifier = null;
hasSpaceAfterAs = false;
collectionValuedPathExpression = null;
hasSpaceAfterCollectionValuedPathExpression = false;
}
/**
* {@inheritDoc}
*/
@Override
protected void toParsedTextEncapsulatedExpression(StringBuilder writer, boolean actual) {
// Collection-valued path expression
if (collectionValuedPathExpression != null) {
writer.append(collectionValuedPathExpression);
}
if (hasSpaceAfterCollectionValuedPathExpression) {
writer.append(SPACE);
}
// AS
if (asIdentifier != null) {
writer.append(actual ? asIdentifier : AS);
}
if (hasSpaceAfterAs) {
writer.append(SPACE);
}
// Entity type
if (entityType != null) {
writer.append(entityType);
}
}
}