package org.drools.rule.builder.dialect.mvel;
/*
* Copyright 2005 JBoss Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.antlr.runtime.RecognitionException;
import org.drools.rule.builder.RuleBuildContext;
import org.mvel.ExpressionCompiler;
import org.mvel.ParserContext;
import org.mvel.integration.impl.MapVariableResolver;
/**
* Expression analyzer.
*
*/
public class MVELExprAnalyzer {
public MVELExprAnalyzer() {
// intentionally left blank.
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Analyze an expression.
*
* @param expr
* The expression to analyze.
* @param availDecls
* Total set of declarations available.
*
* @return The <code>Set</code> of declarations used by the expression.
* @throws RecognitionException
* If an error occurs in the parser.
*/
public MVELAnalysisResult analyzeExpression(final RuleBuildContext context,
final String expr,
final Set[] availableIdentifiers,
final Map localTypes) throws RecognitionException {
MVELAnalysisResult result = null;
if ( expr.trim().length() > 0 ) {
ExpressionCompiler compiler = new ExpressionCompiler( expr );
MVELDialect dialect = (MVELDialect) context.getDialect( "mvel" );
final ParserContext parserContext = new ParserContext( dialect.getImports(),
null,
context.getPkg().getName() + "." + context.getRuleDescr().getClassName() );
for ( Iterator it = dialect.getPackgeImports().values().iterator(); it.hasNext(); ) {
String packageImport = (String) it.next();
parserContext.addPackageImport( packageImport );
}
parserContext.setStrictTypeEnforcement( false );
parserContext.setInterceptors( dialect.getInterceptors() );
compiler.compile( parserContext );
result = analyze( compiler.getParserContextState().getInputs().keySet(),
availableIdentifiers );
result.setMvelVariables( compiler.getParserContextState().getVariables() );
} else {
result = analyze( Collections.EMPTY_SET,
availableIdentifiers );
result.setMvelVariables( new HashMap() );
}
return result;
}
/**
* Analyze an expression.
*
* @param availDecls
* Total set of declarations available.
* @param ast
* The AST for the expression.
*
* @return The <code>Set</code> of declarations used by the expression.
*
* @throws RecognitionException
* If an error occurs in the parser.
*/
private MVELAnalysisResult analyze(final Set identifiers,
final Set[] availableIdentifiers) throws RecognitionException {
MVELAnalysisResult result = new MVELAnalysisResult();
result.setIdentifiers( new ArrayList( identifiers ) );
final Set notBound = new HashSet( identifiers );
final List[] used = new List[availableIdentifiers.length];
for ( int i = 0, length = used.length; i < length; i++ ) {
used[i] = new ArrayList();
}
for ( int i = 0, length = availableIdentifiers.length; i < length; i++ ) {
final Set set = availableIdentifiers[i];
for ( final Iterator it = set.iterator(); it.hasNext(); ) {
final String eachDecl = (String) it.next();
if ( identifiers.contains( eachDecl ) ) {
used[i].add( eachDecl );
notBound.remove( eachDecl );
}
}
}
result.setBoundIdentifiers( used );
result.setNotBoundedIdentifiers( new ArrayList( notBound ) );
return result;
}
}