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/*
* 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;
/**
* A compound expression has a left and right expressions combined by an identifier.
*
* BNF: expression ::= left_expression identifier right_expression
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
public abstract class CompoundExpression extends AbstractExpression {
/**
* Determines whether a whitespace is present after the identifier.
*/
private boolean hasSpaceAfterIdentifier;
/**
* The actual identifier found in the string representation of the JPQL query.
*/
private String identifier;
/**
* The left side of the arithmetic expression.
*/
private AbstractExpression leftExpression;
/**
* The right side of the arithmetic expression.
*/
private AbstractExpression rightExpression;
/**
* Creates a new CompoundExpression.
*
* @param parent The parent of this expression
* @param identifier The identifier of this expression
*/
protected CompoundExpression(AbstractExpression parent, String identifier) {
super(parent, identifier);
}
@Override
public void acceptChildren(ExpressionVisitor visitor) {
getLeftExpression().accept(visitor);
getRightExpression().accept(visitor);
}
@Override
protected final void addChildrenTo(Collection children) {
children.add(getLeftExpression());
children.add(getRightExpression());
}
@Override
protected final void addOrderedChildrenTo(List children) {
// Left expression
if (leftExpression != null) {
children.add(leftExpression);
}
if (hasLeftExpression()) {
children.add(buildStringExpression(SPACE));
}
// Identifier
children.add(buildStringExpression(getText()));
if (hasSpaceAfterIdentifier) {
children.add(buildStringExpression(SPACE));
}
// Right expression
if (rightExpression != null) {
children.add(rightExpression);
}
}
@Override
public JPQLQueryBNF findQueryBNF(Expression expression) {
if (getLeftExpression().isAncestor(expression)) {
return getQueryBNF(getLeftExpressionQueryBNFId());
}
if (getRightExpression().isAncestor(expression)) {
return getQueryBNF(getRightExpressionQueryBNFId());
}
return getParent().findQueryBNF(expression);
}
/**
* Returns the actual identifier found in the string representation of the JPQL query, which has
* the actual case that was used.
*
* @return The JPQL identifier that was actually parsed
*/
public final String getActualIdentifier() {
return identifier;
}
/**
* Returns the JPQL identifier of this expression.
*
* @return The JPQL identifier
*/
public String getIdentifier() {
return super.getText();
}
/**
* Returns the {@link Expression} that represents the first expression, which is before the
* identifier.
*
* @return The expression that was parsed representing the first expression
*/
public final Expression getLeftExpression() {
if (leftExpression == null) {
leftExpression = buildNullExpression();
}
return leftExpression;
}
/**
* Returns the unique identifier of the {@link JPQLQueryBNF} for the left expression.
*
* @return The ID of the BNF used when parsing the expression before the identifier
*/
public abstract String getLeftExpressionQueryBNFId();
/**
* Returns the {@link Expression} that represents the second expression, which is after the
* identifier.
*
* @return The expression that was parsed representing the second expression
*/
public final Expression getRightExpression() {
if (rightExpression == null) {
rightExpression = buildNullExpression();
}
return rightExpression;
}
/**
* Returns the unique identifier of the {@link JPQLQueryBNF} for the right expression.
*
* @return The ID of the BNF used when parsing the expression after the identifier
*/
public abstract String getRightExpressionQueryBNFId();
/**
* Determines whether the first expression of the query was parsed.
*
* @return true if the first expression was parsed; false if it was
* not parsed
*/
public final boolean hasLeftExpression() {
return leftExpression != null &&
!leftExpression.isNull();
}
/**
* Determines whether the second expression of the query was parsed.
*
* @return true if the second expression was parsed; false if it was
* not parsed
*/
public final boolean hasRightExpression() {
return rightExpression != null &&
!rightExpression.isNull();
}
/**
* Determines whether a whitespace was parsed after the identifier.
*
* @return true if there was a whitespace after the identifier; false
* otherwise
*/
public final boolean hasSpaceAfterIdentifier() {
return hasSpaceAfterIdentifier;
}
@Override
protected final void parse(WordParser wordParser, boolean tolerant) {
// Parse the identifier
String identifier = parseIdentifier(wordParser);
this.identifier = wordParser.moveForward(identifier);
setText(identifier);
hasSpaceAfterIdentifier = wordParser.skipLeadingWhitespace() > 0;
// Parse the right expression
rightExpression = parse(wordParser, getRightExpressionQueryBNFId(), tolerant);
if (!hasSpaceAfterIdentifier && (rightExpression != null)) {
hasSpaceAfterIdentifier = true;
}
}
/**
* Parses the identifier of this expression.
*
* @param wordParser The {@link WordParser} containing the text to parse, which starts with the identifier
* @return The identifier for this expression
*/
protected abstract String parseIdentifier(WordParser wordParser);
/**
* Sets the given {@link Expression} to be the first expression of this compound one.
*
* @param leftExpression The expression that was parsed before the identifier
*/
protected final void setLeftExpression(AbstractExpression leftExpression) {
this.leftExpression = leftExpression;
if (leftExpression != null) {
this.leftExpression.setParent(this);
}
}
/**
* Sets the given {@link Expression} to be the second expression of this compound one.
*
* @param rightExpression The expression that was parsed after the identifier
*/
protected final void setRightExpression(AbstractExpression rightExpression) {
this.rightExpression = rightExpression;
if (rightExpression != null) {
this.rightExpression.setParent(this);
}
}
@Override
protected final void toParsedText(StringBuilder writer, boolean actual) {
// Left expression
if (leftExpression != null) {
leftExpression.toParsedText(writer, actual);
}
// Make sure the whitespace is not part of the left expression
if (hasLeftExpression() && (writer.charAt(writer.length() - 1) != ' ')) {
writer.append(SPACE);
}
// Identifier
writer.append(actual ? identifier : getText());
if (hasSpaceAfterIdentifier) {
writer.append(SPACE);
}
// Right expression
if (rightExpression != null) {
rightExpression.toParsedText(writer, actual);
}
}
}