| /* |
| * 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.ArrayList; |
| import java.util.Collection; |
| import java.util.List; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * The <b>FROM</b> clause of a query defines the domain of the query by declaring identification |
| * variables. An identification variable is an identifier declared in the <b>FROM</b> clause of a |
| * query. The domain of the query may be constrained by path expressions. Identification variables |
| * designate instances of a particular entity abstract schema type. The <b>FROM</b> clause can |
| * contain multiple identification variable declarations separated by a comma (,). |
| * |
| * @see FromClause |
| * @see SimpleFromClause |
| * |
| * @version 2.5 |
| * @since 2.3 |
| * @author Pascal Filion |
| */ |
| public abstract class AbstractFromClause extends AbstractExpression { |
| |
| /** |
| * The {@link Expression} that represents the <code><b>AS OF</b></code> clause. |
| * |
| * @since 2.5 |
| */ |
| private AbstractExpression asOfClause; |
| |
| /** |
| * The declaration portion of this <b>FROM</b> clause. |
| */ |
| private AbstractExpression declaration; |
| |
| /** |
| * Determines whether a whitespace was parsed after the identifier <b>FROM</b>. |
| */ |
| private boolean hasSpace; |
| |
| /** |
| * Determines whether there is a whitespace after the hierarchical query clause. |
| * |
| * @since 2.5 |
| */ |
| private boolean hasSpaceAfterHierarchicalQueryClause; |
| |
| /** |
| * Determines whether there is a whitespace after the declaration and either the hierarchical |
| * query clause or the <code><b>AS OF</b></code> clause was parsed. |
| * |
| * @since 2.5 |
| */ |
| private boolean hasSpaceDeclaration; |
| |
| /** |
| * The hierarchical query clause, which holds onto the <code><b>START WITH</b></code> and |
| * <code><b>CONNECT BY</b></code> clauses. |
| * |
| * @since 2.5 |
| */ |
| private AbstractExpression hierarchicalQueryClause; |
| |
| /** |
| * The actual identifier found in the string representation of the JPQL query. |
| */ |
| private String identifier; |
| |
| /** |
| * Creates a new <code>AbstractFromClause</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| protected AbstractFromClause(AbstractExpression parent) { |
| super(parent, FROM); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getDeclaration().accept(visitor); |
| getHierarchicalQueryClause().accept(visitor); |
| getAsOfClause().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getDeclaration()); |
| children.add(getHierarchicalQueryClause()); |
| children.add(getAsOfClause()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // 'FROM' |
| children.add(buildStringExpression(FROM)); |
| |
| // Space between FROM and the declaration |
| if (hasSpace) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Declaration |
| if (declaration != null) { |
| children.add(declaration); |
| } |
| |
| if (hasSpaceDeclaration) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Hierarchical query clause |
| if (hierarchicalQueryClause != null) { |
| children.add(hierarchicalQueryClause); |
| } |
| |
| if (hasSpaceAfterHierarchicalQueryClause) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'AS OF' clause |
| if (asOfClause != null) { |
| children.add(asOfClause); |
| } |
| } |
| |
| /** |
| * Creates a new {@link CollectionExpression} that will wrap the single declaration. |
| * |
| * @return The single declaration represented by a temporary collection |
| */ |
| public final CollectionExpression buildCollectionExpression() { |
| |
| List<AbstractExpression> children = new ArrayList<>(1); |
| children.add((AbstractExpression) getDeclaration()); |
| |
| List<Boolean> commas = new ArrayList<>(1); |
| commas.add(Boolean.FALSE); |
| |
| List<Boolean> spaces = new ArrayList<>(1); |
| spaces.add(Boolean.FALSE); |
| |
| return new CollectionExpression(this, children, commas, spaces, true); |
| } |
| |
| @Override |
| public final JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((declaration != null) && declaration.isAncestor(expression)) { |
| return getQueryBNF(getDeclarationQueryBNFId()); |
| } |
| |
| return super.findQueryBNF(expression); |
| } |
| |
| /** |
| * Returns the actual <b>FROM</b> identifier found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <b>FROM</b> identifier that was actually parsed |
| */ |
| public final String getActualIdentifier() { |
| return identifier; |
| } |
| |
| /** |
| * Returns the {@link Expression} representing the <b>AS OF</b> clause. |
| * |
| * @return The expression representing the <b>AS OF</b> clause |
| */ |
| public final Expression getAsOfClause() { |
| if (asOfClause == null) { |
| asOfClause = buildNullExpression(); |
| } |
| return asOfClause; |
| } |
| |
| /** |
| * Returns the {@link Expression} that represents the declaration of this clause. |
| * |
| * @return The expression that was parsed representing the declaration |
| */ |
| public final Expression getDeclaration() { |
| if (declaration == null) { |
| declaration = buildNullExpression(); |
| } |
| return declaration; |
| } |
| |
| /** |
| * Returns the BNF of the declaration part of this clause. |
| * |
| * @return The BNF of the declaration part of this clause |
| */ |
| public abstract String getDeclarationQueryBNFId(); |
| |
| /** |
| * Returns the {@link Expression} representing the hierarchical query clause. |
| * |
| * @return The expression representing the hierarchical query clause |
| * @since 2.5 |
| */ |
| public final Expression getHierarchicalQueryClause() { |
| if (hierarchicalQueryClause == null) { |
| hierarchicalQueryClause = buildNullExpression(); |
| } |
| return hierarchicalQueryClause; |
| } |
| |
| /** |
| * Determines whether the <b>AS OF</b> clause is defined. |
| * |
| * @return <code>true</code> if the query that got parsed had the <b>AS OF</b> clause |
| */ |
| public final boolean hasAsOfClause() { |
| return asOfClause != null && |
| !asOfClause.isNull(); |
| } |
| |
| /** |
| * Determines whether the declaration of this clause was parsed. |
| * |
| * @return <code>true</code> if the declaration of this clause was parsed; <code>false</code> if |
| * it was not parsed |
| */ |
| public final boolean hasDeclaration() { |
| return declaration != null && |
| !declaration.isNull(); |
| } |
| |
| /** |
| * Determines whether the hierarchical query clause was parsed or not. |
| * |
| * @return <code>true</code> if the query that got parsed had the hierarchical query clause |
| * @since 2.5 |
| */ |
| public final boolean hasHierarchicalQueryClause() { |
| return hierarchicalQueryClause != null && |
| !hierarchicalQueryClause.isNull(); |
| } |
| |
| /** |
| * Determines whether a whitespace was found after the declaration query clause, which will be |
| * <code>true</code> if it's followed by either the hierarchical query clause or the <code><b>AS |
| * OF</b></code> clause. |
| * |
| * @return <code>true</code> if there was a whitespace after the declaration; <code>false</code> otherwise |
| * @since 2.5 |
| */ |
| public final boolean hasSpaceAfterDeclaration() { |
| return hasSpaceDeclaration; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the <b>FROM</b> identifier. |
| * |
| * @return <code>true</code> if a whitespace was parsed after the <b>FROM</b> identifier; |
| * <code>false</code> otherwise |
| */ |
| public final boolean hasSpaceAfterFrom() { |
| return hasSpace; |
| } |
| |
| /** |
| * Determines whether a whitespace was found after the hierarchical query clause. In some cases, |
| * the space is owned by a child of the hierarchical query clause. |
| * |
| * @return <code>true</code> if there was a whitespace after the hierarchical query clause and |
| * owned by this expression; <code>false</code> otherwise |
| * @since 2.5 |
| */ |
| public final boolean hasSpaceAfterHierarchicalQueryClause() { |
| return hasSpaceAfterHierarchicalQueryClause; |
| } |
| |
| @Override |
| protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) { |
| |
| char character = wordParser.character(); |
| |
| // TODO: Add parameter tolerance and check for these 4 signs if tolerant is turned on only |
| // this could happen while parsing an invalid query |
| return wordParser.isArithmeticSymbol(character) || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse 'FROM' |
| identifier = wordParser.moveForward(FROM); |
| |
| hasSpace = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse the declaration |
| declaration = parse(wordParser, getDeclarationQueryBNFId(), tolerant); |
| |
| int count = wordParser.skipLeadingWhitespace(); |
| hasSpaceDeclaration = (count > 0); |
| |
| // Parse hierarchical query clause |
| if (wordParser.startsWithIdentifier(START_WITH) || |
| wordParser.startsWithIdentifier(CONNECT_BY) || |
| wordParser.startsWithIdentifier(ORDER_SIBLINGS_BY)) { |
| |
| hierarchicalQueryClause = new HierarchicalQueryClause(this); |
| hierarchicalQueryClause.parse(wordParser, tolerant); |
| |
| count = wordParser.skipLeadingWhitespace(); |
| hasSpaceAfterHierarchicalQueryClause = (count > 0); |
| } |
| |
| // AS OF clause |
| if (wordParser.startsWithIdentifier(AS_OF)) { |
| asOfClause = new AsOfClause(this); |
| asOfClause.parse(wordParser, tolerant); |
| } |
| else if (hasSpaceAfterHierarchicalQueryClause) { |
| hasSpaceAfterHierarchicalQueryClause = false; |
| wordParser.moveBackward(count); |
| } |
| else if (hierarchicalQueryClause == null) { |
| hasSpaceDeclaration = false; |
| wordParser.moveBackward(count); |
| } |
| } |
| |
| @Override |
| protected boolean shouldParseWithFactoryFirst() { |
| return true; |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // 'FROM' |
| writer.append(actual ? identifier : FROM); |
| |
| if (hasSpace) { |
| writer.append(SPACE); |
| } |
| |
| // Declaration |
| if (declaration != null) { |
| declaration.toParsedText(writer, actual); |
| } |
| |
| if (hasSpaceDeclaration) { |
| writer.append(SPACE); |
| } |
| |
| // Hierarchical query clause |
| if (hierarchicalQueryClause != null) { |
| hierarchicalQueryClause.toParsedText(writer, actual); |
| } |
| |
| if (hasSpaceAfterHierarchicalQueryClause) { |
| writer.append(SPACE); |
| } |
| |
| // AS OF clause |
| if (asOfClause != null) { |
| asOfClause.toParsedText(writer, actual); |
| } |
| } |
| } |