/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* JBoss, Home of Professional Open Source
* Copyright 2013 Red Hat Inc. and/or its affiliates and other contributors
* as indicated by the @authors tag. All rights reserved.
* See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License, v. 2.1.
* This program is distributed in the hope that it will be useful, but WITHOUT A
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public License,
* v.2.1 along with this distribution; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
package org.hibernate.hql;
import org.antlr.runtime.ANTLRStringStream;
import org.antlr.runtime.CommonTokenStream;
import org.antlr.runtime.RecognitionException;
import org.antlr.runtime.Token;
import org.antlr.runtime.tree.CommonTree;
import org.hibernate.hql.ast.origin.hql.parse.HQLLexer;
import org.hibernate.hql.ast.origin.hql.parse.HQLParser;
import org.hibernate.hql.ast.spi.AstProcessingChain;
import org.hibernate.hql.ast.spi.AstProcessor;
import org.hibernate.hql.internal.logging.Log;
import org.hibernate.hql.internal.logging.LoggerFactory;
/**
* A parser for HQL/JPQL queries. Parsing comprises these steps:
* <ul>
* <li>lexing the query</li>
* <li>parsing the query, building up an AST while doing so</li>
* <li>transforming the resulting parse tree using an {@link AstProcessingChain}</li>
* </ul>
*
* @author Gunnar Morling
*/
public class QueryParser {
private static final Log log = LoggerFactory.make();
/**
* Parses the given query string.
*
* @param queryString the query string to parse
* @param processingChain one or more {@link AstProcessor}s which traverse the query parse tree in order to
* normalize/validate it and create the parsing result
* @return the result of this parsing as created by the given processing chain
* @throws ParsingException in case any exception occurs during parsing
*/
public <T> T parseQuery(String queryString, AstProcessingChain<T> processingChain) throws ParsingException {
HQLLexer lexer = new HQLLexer( new ANTLRStringStream( queryString ) );
CommonTokenStream tokens = new CommonTokenStream( lexer );
HQLParser parser = new HQLParser( tokens );
try {
// parser#statement() is the entry point for evaluation of any kind of statement
HQLParser.statement_return r = parser.statement();
if ( parser.hasErrors() ) {
throw log.getInvalidQuerySyntaxException( queryString, parser.getErrorMessages() );
}
String unconsumedTokens = getUnconsumedTokens( tokens );
if ( unconsumedTokens != null ) {
throw log.getInvalidQuerySyntaxDueToUnconsumedTokensException( queryString, unconsumedTokens );
}
CommonTree tree = (CommonTree) r.getTree();
final boolean debugEnabled = log.isDebugEnabled();
for ( AstProcessor processor : processingChain ) {
tree = processor.process( tokens, tree );
if ( debugEnabled ) {
log.debug( "Processed tree: " + tree.toStringTree() );
}
}
return processingChain.getResult();
}
catch (RecognitionException e) {
throw log.getInvalidQuerySyntaxException( queryString, e );
}
}
private String getUnconsumedTokens(CommonTokenStream tokens) {
if ( tokens.index() == tokens.size() - 1 ) {
return null;
}
StringBuilder nonEofEndingTokens = new StringBuilder();
for ( Token endToken : tokens.getTokens( tokens.index(), tokens.size() - 1 ) ) {
// Ignore <EOF> tokens as they might be inserted by the parser
if ( !"<EOF>".equals( endToken.getText() ) ) {
nonEofEndingTokens.append( endToken.getText() );
}
}
return nonEofEndingTokens.length() > 0 ? nonEofEndingTokens.toString() : null;
}
}