| /* |
| * Copyright (c) 2006, 2021 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 v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // 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); |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| acceptUnknownVisitor(visitor); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getCollectionValuedPathExpression().accept(visitor); |
| getEntityType().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getCollectionValuedPathExpression()); |
| children.add(getEntityType()); |
| } |
| |
| @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); |
| } |
| } |
| |
| @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; |
| } |
| |
| @Override |
| 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(); |
| } |
| |
| @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; |
| } |
| |
| @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); |
| } |
| |
| @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); |
| } |
| } |
| |
| @Override |
| protected void removeEncapsulatedExpression() { |
| entityType = null; |
| asIdentifier = null; |
| hasSpaceAfterAs = false; |
| collectionValuedPathExpression = null; |
| hasSpaceAfterCollectionValuedPathExpression = false; |
| } |
| |
| @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); |
| } |
| } |
| } |