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/*
* Copyright (c) 2006, 2020 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;
/**
* An identification variable is a valid identifier declared in the FROM clause of a query.
* All identification variables must be declared in the FROM clause. Identification variables
* cannot be declared in other clauses. An identification variable must not be a reserved identifier
* or have the same name as any entity in the same persistence unit: Identification variables are
* case insensitive. An identification variable evaluates to a value of the type of the expression
* used in declaring the variable.
*
* BNF: identification_variable_declaration ::= range_variable_declaration { join | fetch_join }*
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
public final class IdentificationVariableDeclaration extends AbstractExpression {
/**
* Determines whether there is a space after the range variable declaration.
*/
private boolean hasSpace;
/**
* The unique join (fetch join) or list of join (fetch join) expression or a null
* expression if none was declared.
*/
private AbstractExpression joins;
/**
* Flag used to determine how to check if the parsing is complete.
*/
private boolean parsingJoinExpression;
/**
* The variable declaration, which is the abstract schema name and the variable.
*/
private AbstractExpression rangeVariableDeclaration;
/**
* Creates a new IdentificationVariableDeclaration.
*
* @param parent The parent of this expression
*/
public IdentificationVariableDeclaration(AbstractExpression parent) {
super(parent);
}
@Override
public void accept(ExpressionVisitor visitor) {
visitor.visit(this);
}
@Override
public void acceptChildren(ExpressionVisitor visitor) {
getRangeVariableDeclaration().accept(visitor);
getJoins().accept(visitor);
}
@Override
protected void addChildrenTo(Collection children) {
children.add(getRangeVariableDeclaration());
children.add(getJoins());
}
@Override
protected void addOrderedChildrenTo(List children) {
if (rangeVariableDeclaration != null) {
children.add(rangeVariableDeclaration);
}
if (hasSpace) {
children.add(buildStringExpression(SPACE));
}
if (joins != null) {
children.add(joins);
}
}
/**
* Creates a new {@link CollectionExpression} that will wrap the single join expression.
*
* @return The single join expression represented by a temporary collection
*/
public CollectionExpression buildCollectionExpression() {
List children = new ArrayList(1);
children.add((AbstractExpression) getJoins());
List commas = new ArrayList(1);
commas.add(Boolean.FALSE);
List spaces = new ArrayList(1);
spaces.add(Boolean.FALSE);
return new CollectionExpression(this, children, commas, spaces, true);
}
@Override
public JPQLQueryBNF findQueryBNF(Expression expression) {
if ((rangeVariableDeclaration != null) && rangeVariableDeclaration.isAncestor(expression)) {
return getQueryBNF(RangeVariableDeclarationBNF.ID);
}
if ((joins != null) && joins.isAncestor(expression)) {
return getQueryBNF(InternalJoinBNF.ID);
}
return super.findQueryBNF(expression);
}
/**
* Returns the unique join (fetch join) or the list of joins (fetch joins) expression.
*
* @return The JOIN expression(s) or a null expression if none was declared
*/
public Expression getJoins() {
if (joins == null) {
joins = buildNullExpression();
}
return joins;
}
@Override
public JPQLQueryBNF getQueryBNF() {
return getQueryBNF(IdentificationVariableDeclarationBNF.ID);
}
/**
* Returns the variable declaration, which is the abstract schema name and the identification
* variable.
*
* @return The {@link Expression} representing the range variable declaration
*/
public Expression getRangeVariableDeclaration() {
if (rangeVariableDeclaration == null) {
rangeVariableDeclaration = buildNullExpression();
}
return rangeVariableDeclaration;
}
/**
* Determines whether this declaration has any join expressions.
*
* @return true if at least one join expression was specified; false
* otherwise
*/
public boolean hasJoins() {
return joins != null &&
!joins.isNull();
}
/**
* Determines whether the range variable declaration was parsed.
*
* @return true if the range variable declaration was parsed; false
* otherwise
*/
public boolean hasRangeVariableDeclaration() {
return rangeVariableDeclaration != null &&
!rangeVariableDeclaration.isNull();
}
/**
* Determines whether there is a space after the range variable declaration.
*
* @return true if the range variable declaration is followed by a space,
* false otherwise
*/
public boolean hasSpace() {
return hasSpace;
}
@Override
protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
// Parsing the join expressions
if (parsingJoinExpression) {
return !word.equalsIgnoreCase(JOIN) &&
!word.equalsIgnoreCase(INNER) &&
!word.equalsIgnoreCase(OUTER) &&
!word.equalsIgnoreCase(LEFT);
}
// Parsing the range variable declaration
return word.equalsIgnoreCase(JOIN) ||
word.equalsIgnoreCase(INNER) ||
word.equalsIgnoreCase(LEFT) ||
word.equalsIgnoreCase(OUTER) ||
word.equalsIgnoreCase(IN) ||
super.isParsingComplete(wordParser, word, expression);
}
@Override
protected void parse(WordParser wordParser, boolean tolerant) {
// Parse the range variable declaration
if (tolerant) {
rangeVariableDeclaration = parse(wordParser, RangeVariableDeclarationBNF.ID, tolerant);
}
else {
rangeVariableDeclaration = new RangeVariableDeclaration(this);
rangeVariableDeclaration.parse(wordParser, tolerant);
}
int count = wordParser.skipLeadingWhitespace();
// Parse the JOIN expressions
parsingJoinExpression = true;
joins = parse(wordParser, InternalJoinBNF.ID, tolerant);
// If there are no JOIN expressions and there is more text to parse, then re-add the space so
// it can be owned by a parent expression. The only exception to that is if it's followed by
// a comma, the space will be kept as a virtual space (it will not be part of the string
// representation)
if (!hasJoins() && (wordParser.character() != COMMA)) {
wordParser.moveBackward(count);
}
else {
hasSpace = (count > 0);
}
}
@Override
protected boolean shouldParseWithFactoryFirst() {
return parsingJoinExpression;
}
@Override
protected void toParsedText(StringBuilder writer, boolean actual) {
// Range Variable Declaration
if (rangeVariableDeclaration != null) {
rangeVariableDeclaration.toParsedText(writer, actual);
}
if (hasSpace) {
writer.append(SPACE);
}
// Joins
if (joins != null) {
joins.toParsedText(writer, actual);
}
}
}