/*******************************************************************************
* Copyright (c) 2012, 2015 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 v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* 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;
/**
* Defines a table expression. This allow a non-mapped table to be used in a query. This is not part
* of the JPA functional specification but is EclipseLink specific support.
*
* <div><b>BNF:</b> <code>table_variable_declaration ::= table_expression [AS] identification_variable</code></div>
*
* @version 2.5
* @since 2.4
* @author Pascal Filion
*/
public final class TableVariableDeclaration extends AbstractExpression {
/**
* The actual <b>AS</b> identifier found in the string representation of the JPQL query.
*/
private String asIdentifier;
/**
* Determines whether a whitespace was parsed after <b>AS</b>.
*/
private boolean hasSpaceAfterAs;
/**
* Determines whether a whitespace was parsed after the "root" object.
*/
private boolean hasSpaceAfterTableExpression;
/**
* The {@link Expression} representing the identification variable.
*/
private AbstractExpression identificationVariable;
/**
* The {@link Expression} representing the database table.
*/
private TableExpression tableExpression;
/**
* Creates a new <code>TableVariableDeclaration</code>.
*
* @param parent The parent of this expression
*/
public TableVariableDeclaration(AbstractExpression parent) {
super(parent);
}
/**
* {@inheritDoc}
*/
public void accept(ExpressionVisitor visitor) {
acceptUnknownVisitor(visitor);
}
/**
* {@inheritDoc}
*/
public void acceptChildren(ExpressionVisitor visitor) {
getTableExpression().accept(visitor);
getIdentificationVariable().accept(visitor);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildrenTo(Collection<Expression> children) {
children.add(getTableExpression());
children.add(getIdentificationVariable());
}
/**
* {@inheritDoc}
*/
@Override
protected void addOrderedChildrenTo(List<Expression> children) {
// Table expression
children.add(tableExpression);
// Space
if (hasSpaceAfterTableExpression) {
children.add(buildStringExpression(SPACE));
}
// 'AS'
if (asIdentifier != null) {
children.add(buildStringExpression(AS));
}
if (hasSpaceAfterAs) {
children.add(buildStringExpression(SPACE));
}
// Identification variable
if (identificationVariable != null) {
children.add(identificationVariable);
}
}
/**
* {@inheritDoc}
*/
@Override
public JPQLQueryBNF findQueryBNF(Expression expression) {
if ((tableExpression != null) && tableExpression.isAncestor(expression)) {
return getQueryBNF(TableExpressionBNF.ID);
}
if ((identificationVariable != null) && identificationVariable.isAncestor(expression)) {
return getQueryBNF(IdentificationVariableBNF.ID);
}
return super.findQueryBNF(expression);
}
/**
* Returns the actual <b>AS</b> 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 identification variable.
*
* @return The expression that was parsed representing the identification variable
*/
public Expression getIdentificationVariable() {
if (identificationVariable == null) {
identificationVariable = buildNullExpression();
}
return identificationVariable;
}
/**
* {@inheritDoc}
*/
public JPQLQueryBNF getQueryBNF() {
return getQueryBNF(TableVariableDeclarationBNF.ID);
}
/**
* Returns the {@link TableExpression} that specify the database table.
*
* @return The expression that was parsed specifying the database table
*/
public TableExpression getTableExpression() {
return tableExpression;
}
/**
* 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 identification variable was parsed.
*
* @return <code>true</code> if the identification variable was parsed; <code>false</code> otherwise
*/
public boolean hasIdentificationVariable() {
return identificationVariable != null &&
!identificationVariable.isNull() &&
!identificationVariable.isVirtual();
}
/**
* 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 table expression.
*
* @return <code>true</code> if there was a whitespace after the table expression;
* <code>false</code> otherwise
*/
public boolean hasSpaceAfterTableExpression() {
return hasSpaceAfterTableExpression;
}
/**
* {@inheritDoc}
*/
@Override
protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
return word.equalsIgnoreCase(AS) ||
super.isParsingComplete(wordParser, word, expression);
}
/**
* {@inheritDoc}
*/
@Override
protected void parse(WordParser wordParser, boolean tolerant) {
// Parse the table expression
tableExpression = new TableExpression(this);
tableExpression.parse(wordParser, tolerant);
hasSpaceAfterTableExpression = wordParser.skipLeadingWhitespace() > 0;
// Parse 'AS'
if (wordParser.startsWithIdentifier(AS)) {
asIdentifier = wordParser.moveForward(AS);
hasSpaceAfterAs = wordParser.skipLeadingWhitespace() > 0;
}
// Parse the identification variable
if (tolerant) {
identificationVariable = parse(wordParser, IdentificationVariableBNF.ID, tolerant);
}
else {
identificationVariable = new IdentificationVariable(this, wordParser.word());
identificationVariable.parse(wordParser, tolerant);
}
}
/**
* {@inheritDoc}
*/
@Override
protected void toParsedText(StringBuilder writer, boolean actual) {
// Table expression
tableExpression.toParsedText(writer, actual);
if (hasSpaceAfterTableExpression) {
writer.append(SPACE);
}
// 'AS'
if (asIdentifier != null) {
writer.append(actual ? asIdentifier : AS);
}
if (hasSpaceAfterAs) {
writer.append(SPACE);
}
// Identification variable
if (identificationVariable != null) {
identificationVariable.toParsedText(writer, actual);
}
}
}