| /* |
| * 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.WordParser; |
| |
| /** |
| * The <b>CONNECT BY</b> clause allows selecting rows in a hierarchical order using the hierarchical |
| * query clause. <b>CONNECT BY</b> specifies the relationship between parent rows and child rows of |
| * the hierarchy. |
| * |
| * <div><b>BNF:</b> <code>connectby_clause ::= <b>CONNECT BY</b> { single_valued_object_path_expression | collection_valued_path_expression }</code></div> |
| * |
| * @version 2.5 |
| * @since 2.5 |
| * @author Pascal Filion |
| */ |
| public final class ConnectByClause extends AbstractExpression { |
| |
| /** |
| * The actual identifier found in the string representation of the JPQL query. |
| */ |
| private String actualIdentifier; |
| |
| /** |
| * The conditional expression. |
| */ |
| private AbstractExpression expression; |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>CONNECT BY</b>. |
| */ |
| private boolean hasSpaceAfterConnectBy; |
| |
| /** |
| * Creates a new <code>ConnectByClause</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| public ConnectByClause(AbstractExpression parent) { |
| super(parent, CONNECT_BY); |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| acceptUnknownVisitor(visitor); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getExpression().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getExpression()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // 'CONNECT BY' |
| children.add(buildStringExpression(CONNECT_BY)); |
| |
| if (hasSpaceAfterConnectBy) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Relationship expression |
| if (expression != null) { |
| children.add(expression); |
| } |
| } |
| |
| @Override |
| public JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((this.expression != null) && this.expression.isAncestor(expression)) { |
| return getQueryBNF(CollectionValuedPathExpressionBNF.ID); |
| } |
| |
| return super.findQueryBNF(expression); |
| } |
| |
| /** |
| * Returns the actual <b>CONNECT BY</b> identifier found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <b>CONNECT BY</b> identifier that was actually parsed, or an empty string if it |
| * was not parsed |
| */ |
| public String getActualIdentifier() { |
| return actualIdentifier; |
| } |
| |
| /** |
| * Returns the {@link Expression} representing the relationship expression. |
| * |
| * @return The expression representing the relationship expression |
| */ |
| public Expression getExpression() { |
| if (expression == null) { |
| expression = buildNullExpression(); |
| } |
| return expression; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(ConnectByClauseBNF.ID); |
| } |
| |
| /** |
| * Determines whether the relationship expression was parsed. |
| * |
| * @return <code>true</code> if the relationship expression was parsed; <code>false</code> if it |
| * was not parsed |
| */ |
| public boolean hasExpression() { |
| return expression != null && |
| !expression.isNull(); |
| } |
| |
| /** |
| * Determines whether a whitespace was found after <b>CONNECT BY</b>. |
| * |
| * @return <code>true</code> if there was a whitespace after <b>CONNECT BY</b>; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterConnectBy() { |
| return hasSpaceAfterConnectBy; |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // 'CONNECT BY' |
| actualIdentifier = wordParser.moveForward(CONNECT_BY); |
| |
| hasSpaceAfterConnectBy = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Relationship expression |
| expression = parse(wordParser, InternalConnectByClauseBNF.ID, tolerant); |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // 'CONNECT BY' |
| writer.append(actual ? getActualIdentifier() : getText()); |
| |
| if (hasSpaceAfterConnectBy) { |
| writer.append(SPACE); |
| } |
| |
| // Relationship expression |
| if (expression != null) { |
| expression.toParsedText(writer, actual); |
| } |
| } |
| } |