/*******************************************************************************
* Copyright (c) 2006, 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;
/**
* Range variable declarations allow the developer to designate a "root" for objects which may not
* be reachable by navigation. In order to select values by comparing more than one instance of an
* entity abstract schema type, more than one identification variable ranging over the abstract
* schema type is needed in the <b>FROM</b> clause.
* <p>
* JPA:
* <div><b>BNF:</b> <code>range_variable_declaration ::= abstract_schema_name [AS] identification_variable</code></div>
* <p>
* EclipseLink 2.4:
* <div><b>BNF:</b> <code>range_variable_declaration ::= { root_object } [AS] identification_variable</code></div>
*
* <div><b>BNF:</b> <code>root_object ::= abstract_schema_name | (subquery)</code></div>
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
public final class RangeVariableDeclaration 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 hasSpaceAfterRootObject;
/**
* The {@link Expression} representing the identification variable.
*/
private AbstractExpression identificationVariable;
/**
* The {@link Expression} representing the "root" object.
*/
private AbstractExpression rootObject;
/**
* Determines whether the identification variable is virtual, meaning it's not part of the query
* but is required for proper navigability.
*/
private boolean virtualIdentificationVariable;
/**
* Creates a new <code>RangeVariableDeclaration</code>.
*
* @param parent The parent of this expression
*/
public RangeVariableDeclaration(AbstractExpression parent) {
super(parent);
}
/**
* Creates a new <code>RangeVariableDeclaration</code>, which is used as a virtual declaration.
*
* @param entityName The name of the entity to be accessible with the given variable name
* @param variableName The identification variable used to navigate to the entity
*/
public RangeVariableDeclaration(String entityName, String variableName) {
super(null);
rootObject = new AbstractSchemaName(this, entityName);
identificationVariable = new IdentificationVariable(this, variableName);
}
/**
* {@inheritDoc}
*/
public void accept(ExpressionVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
public void acceptChildren(ExpressionVisitor visitor) {
getRootObject().accept(visitor);
getIdentificationVariable().accept(visitor);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildrenTo(Collection<Expression> children) {
children.add(getRootObject());
children.add(getIdentificationVariable());
}
/**
* {@inheritDoc}
*/
@Override
protected void addOrderedChildrenTo(List<Expression> children) {
// "Root" object
if (rootObject != null) {
children.add(rootObject);
}
// Space
if (hasSpaceAfterRootObject) {
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 ((rootObject != null) && rootObject.isAncestor(expression)) {
return getQueryBNF(RangeDeclarationBNF.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(RangeVariableDeclarationBNF.ID);
}
/**
* Returns the {@link Expression} that represents the "root" object.
*
* @return The expression that was parsed representing the "root" object
*/
public Expression getRootObject() {
if (rootObject == null) {
rootObject = buildNullExpression();
}
return rootObject;
}
/**
* 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 the "root" object was parsed.
*
* @return <code>true</code> if the "root" object was parsed; <code>false</code> otherwise
*/
public boolean hasRootObject() {
return rootObject != null &&
!rootObject.isNull();
}
/**
* 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 "root" object.
*
* @return <code>true</code> if there was a whitespace after "root" object;
* <code>false</code> otherwise
*/
public boolean hasSpaceAfterRootObject() {
return hasSpaceAfterRootObject;
}
/**
* Determines whether this identification variable is virtual, meaning it's not part of the
* query but is required for proper navigability.
*
* @return <code>true</code> if this identification variable was virtually created to fully
* qualify path expression; <code>false</code> if it was parsed
*/
public boolean hasVirtualIdentificationVariable() {
return virtualIdentificationVariable;
}
/**
* {@inheritDoc}
*/
@Override
protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
return word.equalsIgnoreCase(AS) ||
word.equalsIgnoreCase(SET) ||
word.equalsIgnoreCase(INNER) ||
word.equalsIgnoreCase(JOIN) ||
word.equalsIgnoreCase(LEFT) ||
super.isParsingComplete(wordParser, word, expression);
}
/**
* {@inheritDoc}
*/
@Override
protected void parse(WordParser wordParser, boolean tolerant) {
// Parse the "root" object
rootObject = parse(wordParser, RangeDeclarationBNF.ID, tolerant);
hasSpaceAfterRootObject = wordParser.skipLeadingWhitespace() > 0;
// Parse 'AS'
if (wordParser.startsWithIdentifier(AS)) {
asIdentifier = wordParser.moveForward(AS);
hasSpaceAfterAs = wordParser.skipLeadingWhitespace() > 0;
}
// Special case when parsing the range variable declaration of an UPDATE clause that does
// not have an identification variable, e.g. "UPDATE DateTime SET date = CURRENT_DATE"
if (!wordParser.startsWithIdentifier(SET)) {
if (tolerant) {
identificationVariable = parse(wordParser, IdentificationVariableBNF.ID, tolerant);
}
else {
identificationVariable = new IdentificationVariable(this, wordParser.word());
identificationVariable.parse(wordParser, tolerant);
}
}
}
/**
* Sets a virtual identification variable because the "root" object was parsed without one. This
* is valid in an <b>UPDATE</b> and <b>DELETE</b> queries. Example:
* <p>
* <code>UPDATE DateTime SET date = CURRENT_DATE</code>
* <p>
* is equivalent to
* <p>
* <code>UPDATE DateTime d SET d.date = CURRENT_DATE</code>
*
* @param variableName A virtual identification variable that will identify the "root" object
*/
public void setVirtualIdentificationVariable(String variableName) {
virtualIdentificationVariable = true;
identificationVariable = new IdentificationVariable(this, variableName, true);
}
/**
* Sets a virtual identification variable to qualify the "root" object. The "root" object is a
* derived path that does not start with an identification variable. Example:
* <p>
* <code>UPDATE Employee SET firstName = 'MODIFIED'
* WHERE (SELECT COUNT(m) FROM managedEmployees m) {@literal >} 0</code>
* <p>
* <i>'managedEmployees'</i> is a derived path and will become qualified with the given virtual
* identification variable.
*
* @param variableName The identification variable that was generated to qualify the "root" object
* @param path The path that was parsed as a "root" object
*/
public void setVirtualIdentificationVariable(String variableName, String path) {
CollectionValuedPathExpression expression = new CollectionValuedPathExpression(this, path);
expression.setVirtualIdentificationVariable(variableName);
rootObject = expression;
}
/**
* {@inheritDoc}
*/
@Override
protected boolean shouldParseWithFactoryFirst() {
return false;
}
/**
* {@inheritDoc}
*/
@Override
protected void toParsedText(StringBuilder writer, boolean actual) {
// "Root" object
if (rootObject != null) {
rootObject.toParsedText(writer, actual);
}
if (hasSpaceAfterRootObject) {
writer.append(SPACE);
}
// 'AS'
if (asIdentifier != null) {
writer.append(actual ? asIdentifier : AS);
}
if (hasSpaceAfterAs) {
writer.append(SPACE);
}
// Identification variable
if ((identificationVariable != null) && !virtualIdentificationVariable) {
identificationVariable.toParsedText(writer, actual);
}
}
}