| /* |
| * 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 org.eclipse.persistence.jpa.jpql.ExpressionTools; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * An <b>EXISTS</b> expression is a predicate that is <code>true</code> only if the result of the |
| * subquery consists of one or more values and that is <code>false</code> otherwise. |
| * |
| * <div><b>BNF:</b> <code>exists_expression ::= [NOT] EXISTS(subquery)</code></div> |
| * |
| * @version 2.5 |
| * @since 2.3 |
| * @author Pascal Filion |
| */ |
| public final class ExistsExpression extends AbstractSingleEncapsulatedExpression { |
| |
| /** |
| * The actual <b>NOT</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String notIdentifier; |
| |
| /** |
| * Creates a new <code>ExistsExpression</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| public ExistsExpression(AbstractExpression parent) { |
| super(parent, EXISTS); |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| public String getEncapsulatedExpressionQueryBNFId() { |
| return SubqueryBNF.ID; |
| } |
| |
| /** |
| * Returns the actual <b>NOT</b> identifier found in the string representation of the JPQL query, |
| * which has the actual case that was used. |
| * |
| * @return The <b>NOT</b> identifier that was actually parsed, or an empty string if it was not |
| * parsed |
| */ |
| public String getActualNotIdentifier() { |
| return (notIdentifier != null) ? notIdentifier : ExpressionTools.EMPTY_STRING; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(ExistsExpressionBNF.ID); |
| } |
| |
| /** |
| * Determines whether the identifier <b>NOT</b> was parsed. |
| * |
| * @return <code>true</code> if the identifier <b>NOT</b> was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasNot() { |
| return (notIdentifier != null); |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse 'NOT' |
| if (wordParser.startsWithIgnoreCase('N')) { |
| int position = wordParser.position(); |
| notIdentifier = wordParser.substring(position, position + 3); |
| setText(NOT_EXISTS); |
| } |
| |
| super.parse(wordParser, tolerant); |
| } |
| |
| @Override |
| protected AbstractExpression parse(WordParser wordParser, String queryBNFId, boolean tolerant) { |
| |
| if (tolerant) { |
| return super.parse(wordParser, queryBNFId, tolerant); |
| } |
| |
| SimpleSelectStatement expression = new SimpleSelectStatement(this); |
| expression.parse(wordParser, tolerant); |
| return expression; |
| } |
| } |