| /* |
| * 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.ExpressionTools; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * <div><b>BNF:</b> <code>general_case_expression ::= CASE when_clause {when_clause}* ELSE scalar_expression END</code></div> |
| * or |
| * <div><b>BNF:</b> <code>simple_case_expression ::= CASE case_operand simple_when_clause {simple_when_clause}* ELSE scalar_expression END</code></div> |
| * |
| * @version 2.5 |
| * @since 2.3 |
| * @author Pascal Filion |
| */ |
| public final class CaseExpression extends AbstractExpression { |
| |
| /** |
| * The actual <b>CASE</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String caseIdentifier; |
| |
| /** |
| * The {@link Expression} representing the case operand. |
| */ |
| private AbstractExpression caseOperand; |
| |
| /** |
| * The {@link Expression} representing the <b>ELSE</b> expression. |
| */ |
| private AbstractExpression elseExpression; |
| |
| /** |
| * The actual <b>ELSE</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String elseIdentifier; |
| |
| /** |
| * The actual <b>END</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String endIdentifier; |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>CASE</b>. |
| */ |
| private boolean hasSpaceAfterCase; |
| |
| /** |
| * Determines whether a whitespace was parsed after the case operand. |
| */ |
| private boolean hasSpaceAfterCaseOperand; |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>ELSE</b>. |
| */ |
| private boolean hasSpaceAfterElse; |
| |
| /** |
| * Determines whether a whitespace was parsed after the <b>BETWEEN</b> expression. |
| */ |
| private boolean hasSpaceAfterElseExpression; |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>WHEN</b> clause. |
| */ |
| private boolean hasSpaceAfterWhenClauses; |
| |
| /** |
| * Used to determine how to check if the parsing is complete. |
| */ |
| private ParsingType parsingType; |
| |
| /** |
| * The {@link Expression} representing the <b>WHEN</b> clauses. |
| */ |
| private AbstractExpression whenClauses; |
| |
| /** |
| * Creates a new <code>CaseExpression</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| public CaseExpression(AbstractExpression parent) { |
| super(parent, CASE); |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getCaseOperand().accept(visitor); |
| getWhenClauses().accept(visitor); |
| getElseExpression().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getCaseOperand()); |
| children.add(getWhenClauses()); |
| children.add(getElseExpression()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // 'CASE' |
| children.add(buildStringExpression(CASE)); |
| |
| if (hasSpaceAfterCase) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Case operand |
| if (caseOperand != null) { |
| children.add(caseOperand); |
| } |
| |
| if (hasSpaceAfterCaseOperand) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // WHEN clauses |
| if (whenClauses != null) { |
| children.add(whenClauses); |
| } |
| |
| if (hasSpaceAfterWhenClauses) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'ELSE' |
| if (elseIdentifier != null) { |
| children.add(buildStringExpression(ELSE)); |
| } |
| |
| if (hasSpaceAfterElse) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Else expression |
| if (elseExpression != null) { |
| children.add(elseExpression); |
| } |
| |
| if (hasSpaceAfterElseExpression) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'END' |
| if (endIdentifier != null) { |
| children.add(buildStringExpression(END)); |
| } |
| } |
| |
| @Override |
| public JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((caseOperand != null) && caseOperand.isAncestor(expression)) { |
| return getQueryBNF(CaseOperandBNF.ID); |
| } |
| |
| if ((whenClauses != null) && whenClauses.isAncestor(expression)) { |
| return getQueryBNF(WhenClauseBNF.ID); |
| } |
| |
| if ((elseExpression != null) && elseExpression.isAncestor(expression)) { |
| return getQueryBNF(ElseExpressionBNF.ID); |
| } |
| |
| return super.findQueryBNF(expression); |
| } |
| |
| /** |
| * Returns the actual <b>CASE</b> identifier found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <b>CASE</b> identifier that was actually parsed |
| */ |
| public String getActualCaseIdentifier() { |
| return caseIdentifier; |
| } |
| |
| /** |
| * Returns the actual <b>ELSE</b> identifier found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <b>ELSE</b> identifier that was actually parsed, or an empty string if it was not |
| * parsed |
| */ |
| public String getActualElseIdentifier() { |
| return (elseIdentifier != null) ? elseIdentifier : ExpressionTools.EMPTY_STRING; |
| } |
| |
| /** |
| * Returns the actual <b>END</b> identifier found in the string representation of the JPQL query, |
| * which has the actual case that was used. |
| * |
| * @return The <b>END</b> identifier that was actually parsed, or an empty string if it was not |
| * parsed |
| */ |
| public String getActualEndIdentifier() { |
| return (endIdentifier != null) ? endIdentifier : ExpressionTools.EMPTY_STRING; |
| } |
| |
| /** |
| * Returns the {@link Expression} that represents the <b>CASE</b> operand. |
| * |
| * @return The expression that was parsed representing the <b>CASE</b> operand |
| */ |
| public Expression getCaseOperand() { |
| if (caseOperand == null) { |
| caseOperand = buildNullExpression(); |
| } |
| return caseOperand; |
| } |
| |
| /** |
| * Returns the {@link Expression} that represents the <b>ELSE</b> operand. |
| * |
| * @return The expression that was parsed representing the <b>ELSE</b> operand |
| */ |
| public AbstractExpression getElseExpression() { |
| if (elseExpression == null) { |
| elseExpression = buildNullExpression(); |
| } |
| return elseExpression; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(GeneralCaseExpressionBNF.ID); |
| } |
| |
| /** |
| * Returns the {@link Expression} that represents the <b>WHEN</b> clauses. |
| * |
| * @return The expression that was parsed representing the <b>WHEN</b> clauses |
| */ |
| public AbstractExpression getWhenClauses() { |
| if (whenClauses == null) { |
| whenClauses = buildNullExpression(); |
| } |
| return whenClauses; |
| } |
| |
| /** |
| * Determines whether the <b>CASE</b> operand was parsed. |
| * |
| * @return <code>true</code> if the <b>CASE</b> operand was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasCaseOperand() { |
| return caseOperand != null && |
| !caseOperand.isNull(); |
| } |
| |
| /** |
| * Determines whether the identifier <b>ELSE</b> was parsed. |
| * |
| * @return <code>true</code> if the identifier <b>ELSE</b> was parsed; <code>false</code> |
| * otherwise |
| */ |
| public boolean hasElse() { |
| return elseIdentifier != null; |
| } |
| |
| /** |
| * Determines whether the <b>ELSE</b> expression was parsed. |
| * |
| * @return <code>true</code> if the <b>ELSE</b> expression was parsed; <code>false</code> |
| * otherwise |
| */ |
| public boolean hasElseExpression() { |
| return elseExpression != null && |
| !elseExpression.isNull(); |
| } |
| |
| /** |
| * Determines whether the identifier <b>END</b> was parsed. |
| * |
| * @return <code>true</code> if the identifier <b>END</b> was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasEnd() { |
| return endIdentifier != null; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>CASE</b>. |
| * |
| * @return <code>true</code> if there was a whitespace after <b>CASE</b>; <code>false</code> |
| * otherwise |
| */ |
| public boolean hasSpaceAfterCase() { |
| return hasSpaceAfterCase; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the case operand. |
| * |
| * @return <code>true</code> if there was a whitespace after the case operand; <code>false</code> |
| * otherwise |
| */ |
| public boolean hasSpaceAfterCaseOperand() { |
| return hasSpaceAfterCaseOperand; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>ELSE</b>. |
| * |
| * @return <code>true</code> if there was a whitespace after <b>ELSE</b>; <code>false</code> |
| * otherwise |
| */ |
| public boolean hasSpaceAfterElse() { |
| return hasSpaceAfterElse; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the else expression. |
| * |
| * @return <code>true</code> if there was a whitespace after the else expression; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterElseExpression() { |
| return hasSpaceAfterElseExpression; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the <b>WHEN</b> clause. |
| * |
| * @return <code>true</code> if there was a whitespace after the <b>WHEN</b> |
| * clause; <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterWhenClauses() { |
| return hasSpaceAfterWhenClauses; |
| } |
| |
| /** |
| * Determines whether the <b>WHEN</b> clauses were parsed. |
| * |
| * @return <code>true</code> if the <b>WHEN</b> clauses were parsed; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasWhenClauses() { |
| return whenClauses != null && |
| !whenClauses.isNull(); |
| } |
| |
| @Override |
| protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) { |
| |
| // 'CASE' |
| if (parsingType == ParsingType.CASE) { |
| return word.equalsIgnoreCase(WHEN) || |
| word.equalsIgnoreCase(ELSE) || |
| word.equalsIgnoreCase(END) || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| // 'WHEN' |
| if (parsingType == ParsingType.WHEN) { |
| return word.equalsIgnoreCase(ELSE) || |
| word.equalsIgnoreCase(END) || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| // 'ELSE' |
| return word.equalsIgnoreCase(END) || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse 'CASE' |
| caseIdentifier = wordParser.moveForward(CASE); |
| hasSpaceAfterCase = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse case operand |
| parsingType = ParsingType.CASE; |
| |
| if (!wordParser.startsWithIdentifier(WHEN)) { |
| caseOperand = parse(wordParser, CaseOperandBNF.ID, tolerant); |
| hasSpaceAfterCaseOperand = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Parse the WHEN clauses |
| parsingType = ParsingType.WHEN; |
| whenClauses = parse(wordParser, WhenClauseBNF.ID, tolerant); |
| hasSpaceAfterWhenClauses = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse 'ELSE' |
| if (!tolerant || wordParser.startsWithIdentifier(ELSE)) { |
| elseIdentifier = wordParser.moveForward(ELSE); |
| hasSpaceAfterElse = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Parse the ELSE expression |
| parsingType = ParsingType.ELSE; |
| elseExpression = parse(wordParser, ElseExpressionBNF.ID, tolerant); |
| hasSpaceAfterElseExpression = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse 'END' |
| if (!tolerant || wordParser.startsWithIdentifier(END)) { |
| endIdentifier = wordParser.moveForward(END); |
| } |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // 'CASE' |
| writer.append(actual ? caseIdentifier : CASE); |
| |
| if (hasSpaceAfterCase) { |
| writer.append(SPACE); |
| } |
| |
| // Case Operand |
| if (caseOperand != null) { |
| caseOperand.toParsedText(writer, actual); |
| } |
| |
| if (hasSpaceAfterCaseOperand) { |
| writer.append(SPACE); |
| } |
| |
| // When clauses |
| if (whenClauses != null) { |
| whenClauses.toParsedText(writer, actual); |
| } |
| |
| if (hasSpaceAfterWhenClauses) { |
| writer.append(SPACE); |
| } |
| |
| // 'ELSE' |
| if (elseIdentifier != null) { |
| writer.append(actual ? elseIdentifier : ELSE); |
| } |
| |
| if (hasSpaceAfterElse) { |
| writer.append(SPACE); |
| } |
| |
| // Else expression |
| if (elseExpression != null) { |
| elseExpression.toParsedText(writer, actual); |
| } |
| |
| if (hasSpaceAfterElseExpression) { |
| writer.append(SPACE); |
| } |
| |
| // 'END' |
| if (endIdentifier != null) { |
| writer.append(actual ? endIdentifier : END); |
| } |
| } |
| |
| /** |
| * A enumeration used to determine how {@link CaseExpression#isParsingComplete(WordParser, String, Expression)} |
| * should behaves. |
| */ |
| private enum ParsingType { |
| CASE, |
| ELSE, |
| WHEN |
| } |
| } |