| /* |
| * Copyright (c) 2012, 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.List; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * The <b>CAST</b> function cast value to a different type. The database type is the second parameter, |
| * and can be any valid database type including size and scale. |
| * |
| * <div><b>BNF:</b> <code>expression ::= CAST(scalar_expression [AS] database_type)</code></div> |
| * |
| * @see DatabaseType |
| * |
| * @version 2.5 |
| * @since 2.4 |
| * @author James Sutherland |
| */ |
| public final class CastExpression extends AbstractSingleEncapsulatedExpression { |
| |
| /** |
| * The actual <b>AS</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String asIdentifier; |
| |
| /** |
| * The {@link Expression} representing the database type to cast to. |
| */ |
| private AbstractExpression databaseType; |
| |
| /** |
| * Determines whether a space was parsed after the identifier <b>AS</b>. |
| */ |
| private boolean hasSpaceAfterAs; |
| |
| /** |
| * Determines whether a space was parsed after the expression. |
| */ |
| private boolean hasSpaceAfterExpression; |
| |
| /** |
| * Flag used to determine how to stop parsing based on what is being parsed. |
| */ |
| private boolean parsingDatabaseType; |
| |
| /** |
| * This flag is used to prevent the parsing from using any {@link ExpressionFactory} before |
| * going through the fallback procedure. This is necessary because only a {@link DatabaseType} |
| * should be created, even if the database type is a JPQL identifier (eg: <code>TIMESTAMP</code>). |
| */ |
| private boolean shouldParseWithFactoryFirst; |
| |
| /** |
| * Creates a new <code>CastExpression</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| public CastExpression(AbstractExpression parent) { |
| super(parent, CAST); |
| shouldParseWithFactoryFirst = true; |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| acceptUnknownVisitor(visitor); |
| } |
| |
| @Override |
| protected void addOrderedEncapsulatedExpressionTo(List<Expression> children) { |
| |
| // Value |
| super.addOrderedEncapsulatedExpressionTo(children); |
| |
| if (hasSpaceAfterExpression) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'AS' |
| if (asIdentifier != null) { |
| children.add(buildStringExpression(AS)); |
| } |
| |
| if (hasSpaceAfterAs) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| if (hasDatabaseType()) { |
| children.add(databaseType); |
| } |
| } |
| |
| @Override |
| public String getEncapsulatedExpressionQueryBNFId() { |
| return ScalarExpressionBNF.ID; |
| } |
| |
| /** |
| * Returns the database type to cast to. |
| * |
| * @return The {@link Expression} representing the database type |
| */ |
| public Expression getDatabaseType() { |
| return databaseType; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(CastExpressionBNF.ID); |
| } |
| |
| /** |
| * Determines whether the identifier <b>AS</b> was part of the query. |
| * |
| * @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 database type was parsed or not. |
| * |
| * @return <code>true</code> if the database type was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasDatabaseType() { |
| return databaseType != null && |
| !databaseType.isNull(); |
| } |
| |
| @Override |
| public boolean hasEncapsulatedExpression() { |
| return super.hasEncapsulatedExpression() || (asIdentifier != null) || hasDatabaseType(); |
| } |
| |
| /** |
| * Determines whether something was parsed after the left parenthesis and before the |
| * <code><b>AS</b></code> identifier. |
| * |
| * @return <code>true</code> the expression to be cast was parsed; <code>false</code> otherwise |
| * @since 2.5 |
| */ |
| public boolean hasScalarExpression() { |
| return super.hasEncapsulatedExpression(); |
| } |
| |
| /** |
| * Determines whether a whitespace parsed after <b>AS</b>. |
| * |
| * @return <code>true</code> if there was a whitespace parsed after <b>AS</b>; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterAs() { |
| return hasSpaceAfterAs; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the expression. |
| * |
| * @return <code>true</code> if there was a whitespace parsed after the expression; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterExpression() { |
| return hasSpaceAfterExpression; |
| } |
| |
| @Override |
| protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) { |
| |
| if (parsingDatabaseType) { |
| return super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| ExpressionFactory factory = getQueryBNF(getEncapsulatedExpressionQueryBNFId()).getExpressionFactory(word); |
| |
| // The first check is used to stop parsing the scalar expression, |
| // example: CAST(e.firstName NUMERIC(2, 3)) and "NUMERIC" is the current word, |
| // it cannot be part of the scalar expression but will be the database type |
| // TODO: Add support for tolerance and the scalar expression is invalid, like |
| // having 'x AND y', it probably should be parsed in its entirety |
| return (factory == null && expression != null) || |
| word.equalsIgnoreCase(AS) || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| @Override |
| protected void parseEncapsulatedExpression(WordParser wordParser, |
| int whitespaceCount, |
| boolean tolerant) { |
| |
| // Parse the value |
| super.parseEncapsulatedExpression(wordParser, whitespaceCount, tolerant); |
| |
| hasSpaceAfterExpression = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse 'AS' |
| if (wordParser.startsWithIdentifier(AS)) { |
| asIdentifier = wordParser.moveForward(AS); |
| hasSpaceAfterAs = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Parse the database type |
| if (!wordParser.isTail()) { |
| parsingDatabaseType = true; |
| if (tolerant) { |
| databaseType = parse(wordParser, DatabaseTypeQueryBNF.ID, tolerant); |
| } |
| else { |
| databaseType = new DatabaseType(this, wordParser.word()); |
| databaseType.parse(wordParser, tolerant); |
| } |
| } |
| } |
| |
| @Override |
| protected void removeEncapsulatedExpression() { |
| super.removeEncapsulatedExpression(); |
| asIdentifier = null; |
| databaseType = null; |
| hasSpaceAfterAs = false; |
| hasSpaceAfterExpression = false; |
| } |
| |
| @Override |
| protected boolean shouldParseWithFactoryFirst() { |
| return shouldParseWithFactoryFirst; |
| } |
| |
| @Override |
| protected void toParsedTextEncapsulatedExpression(StringBuilder writer, boolean actual) { |
| |
| // Value |
| super.toParsedTextEncapsulatedExpression(writer, actual); |
| |
| if (hasSpaceAfterExpression) { |
| writer.append(SPACE); |
| } |
| |
| // 'AS' |
| if (asIdentifier != null) { |
| writer.append(actual ? asIdentifier : AS); |
| } |
| |
| if (hasSpaceAfterAs) { |
| writer.append(SPACE); |
| } |
| |
| // Database type |
| if (databaseType != null) { |
| databaseType.toParsedText(writer, actual); |
| } |
| } |
| } |