| /* |
| * 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; |
| |
| /** |
| * A result variable may be used to name a select item in the query result. |
| * |
| * <div><b>BNF:</b> <code>select_item ::= select_expression [[AS] result_variable]</code></div> |
| * |
| * @version 2.5 |
| * @since 2.3 |
| * @author Pascal Filion |
| */ |
| public final class ResultVariable 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 the identifier <b>AS</b>. |
| */ |
| private boolean hasSpaceAfterAs; |
| |
| /** |
| * The {@link Expression} used |
| */ |
| private AbstractExpression resultVariable; |
| |
| /** |
| * The {@link Expression} representing the select expression. |
| */ |
| private AbstractExpression selectExpression; |
| |
| /** |
| * Creates a new <code>ResultVariable</code>. |
| * |
| * @param parent The parent of this expression |
| * @param selectExpression The expression that represents the select expression, which will have |
| * a variable assigned to it |
| */ |
| public ResultVariable(AbstractExpression parent, AbstractExpression selectExpression) { |
| super(parent); |
| |
| if (selectExpression != null) { |
| this.selectExpression = selectExpression; |
| this.selectExpression.setParent(this); |
| } |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getSelectExpression().accept(visitor); |
| getResultVariable().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getSelectExpression()); |
| children.add(getResultVariable()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // Select expression |
| if (selectExpression != null) { |
| children.add(selectExpression); |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'AS' |
| if (asIdentifier != null) { |
| children.add(buildStringExpression(AS)); |
| } |
| |
| if (hasSpaceAfterAs) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Result variable |
| if (resultVariable != null) { |
| children.add(resultVariable); |
| } |
| } |
| |
| @Override |
| public JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((selectExpression != null) && selectExpression.isAncestor(expression)) { |
| return getQueryBNF(SelectExpressionBNF.ID); |
| } |
| |
| if ((resultVariable != null) && resultVariable.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; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(ResultVariableBNF.ID); |
| } |
| |
| /** |
| * Returns the {@link Expression} representing the result variable. |
| * |
| * @return The expression for the result variable |
| */ |
| public Expression getResultVariable() { |
| if (resultVariable == null) { |
| resultVariable = buildNullExpression(); |
| } |
| return resultVariable; |
| } |
| |
| /** |
| * Returns the {@link Expression} representing the select expression. |
| * |
| * @return The expression for the select expression |
| */ |
| public Expression getSelectExpression() { |
| if (selectExpression == null) { |
| selectExpression = buildNullExpression(); |
| } |
| return selectExpression; |
| } |
| |
| /** |
| * Determines whether the identifier <b>AS</b> was parsed or not. |
| * |
| * @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 result variable was parsed. |
| * |
| * @return <code>true</code> if the result variable was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasResultVariable() { |
| return resultVariable != null && |
| !resultVariable.isNull(); |
| } |
| |
| /** |
| * Determines whether a select expression was defined for this result variable. |
| * |
| * @return <code>true</code> if the select expression was parsed; <code>false</code> if the |
| * result variable was parsed without one |
| */ |
| public boolean hasSelectExpression() { |
| return selectExpression != null && |
| !selectExpression.isNull(); |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the identifier <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; |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse 'AS' |
| if (wordParser.startsWithIdentifier(AS)) { |
| asIdentifier = wordParser.moveForward(2); |
| hasSpaceAfterAs = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Parse the result variable |
| if (tolerant) { |
| resultVariable = parse(wordParser, IdentificationVariableBNF.ID, tolerant); |
| } |
| else { |
| resultVariable = new IdentificationVariable(this, wordParser.word()); |
| resultVariable.parse(wordParser, tolerant); |
| } |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // Select expression |
| if (selectExpression != null) { |
| selectExpression.toParsedText(writer, actual); |
| |
| if ((writer.length() > 0) && (writer.charAt(writer.length() - 1) != SPACE)) { |
| writer.append(SPACE); |
| } |
| } |
| |
| // 'AS' |
| if (asIdentifier != null) { |
| writer.append(actual ? asIdentifier : AS); |
| } |
| |
| if (hasSpaceAfterAs) { |
| writer.append(SPACE); |
| } |
| |
| // Result variable |
| if (resultVariable != null) { |
| resultVariable.toParsedText(writer, actual); |
| } |
| } |
| } |