org.drools.rule.builder.dialect.mvel.MVELExprAnalyzer Maven / Gradle / Ivy
/*
* 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.
*/
package org.drools.rule.builder.dialect.mvel;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.antlr.runtime.RecognitionException;
import org.drools.base.EvaluatorWrapper;
import org.drools.compiler.BoundIdentifiers;
import org.drools.compiler.DescrBuildError;
import org.drools.definition.rule.Rule;
import org.drools.lang.descr.BaseDescr;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.builder.PackageBuildContext;
import org.drools.rule.builder.RuleBuildContext;
import org.mvel2.MVEL;
import org.mvel2.ParserConfiguration;
import org.mvel2.ParserContext;
import org.mvel2.util.PropertyTools;
import static org.drools.rule.builder.dialect.DialectUtil.copyErrorLocation;
/**
* Expression analyzer.
*/
public class MVELExprAnalyzer {
public MVELExprAnalyzer() {
// intentionally left blank.
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Analyze an expression.
*
* @param expr
* The expression to analyze.
* @param availableIdentifiers
* Total set of declarations available.
*
* @return The Set of declarations used by the expression.
* @throws RecognitionException
* If an error occurs in the parser.
*/
@SuppressWarnings("unchecked")
public MVELAnalysisResult analyzeExpression(final PackageBuildContext context,
final String expr,
final BoundIdentifiers availableIdentifiers,
final Map> localTypes,
String contextIndeifier,
Class kcontextClass) {
MVELAnalysisResult result;
if ( expr.trim().length() > 0 ) {
MVEL.COMPILER_OPT_ALLOW_NAKED_METH_CALL = true;
MVEL.COMPILER_OPT_ALLOW_OVERRIDE_ALL_PROPHANDLING = true;
MVEL.COMPILER_OPT_ALLOW_RESOLVE_INNERCLASSES_WITH_DOTNOTATION = true;
MVEL.COMPILER_OPT_SUPPORT_JAVA_STYLE_CLASS_LITERALS = true;
MVELDialect dialect = (MVELDialect) context.getDialect( "mvel" );
MVELDialectRuntimeData data = ( MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData( "mvel" );
ParserConfiguration conf = data.getParserConfiguration();
conf.setClassLoader( context.getPackageBuilder().getRootClassLoader() );
// first compilation is for verification only
// @todo proper source file name
final ParserContext parserContext1 = new ParserContext( conf );
if ( localTypes != null ) {
for ( Entry entry : localTypes.entrySet() ) {
parserContext1.addInput( (String) entry.getKey(),
(Class) entry.getValue() );
}
}
if ( availableIdentifiers.getThisClass() != null ) {
parserContext1.addInput( "this",
availableIdentifiers.getThisClass() );
}
if ( availableIdentifiers.getOperators() != null ) {
for ( Entry opEntry : availableIdentifiers.getOperators().entrySet() ) {
parserContext1.addInput( opEntry.getKey(), opEntry.getValue().getClass() );
}
}
parserContext1.setStrictTypeEnforcement( false );
parserContext1.setStrongTyping( false );
parserContext1.setInterceptors( dialect.getInterceptors() );
Class< ? > returnType;
try {
returnType = MVEL.analyze( expr,
parserContext1 );
} catch ( Exception e ) {
BaseDescr base = (context instanceof RuleBuildContext) ? ((RuleBuildContext)context).getRuleDescr() : context.getParentDescr();
copyErrorLocation(e, context.getParentDescr());
context.addError( new DescrBuildError( base,
context.getParentDescr(),
null,
"Unable to Analyse Expression " + expr + ":\n" + e.getMessage() ) );
return null;
}
Set requiredInputs = new HashSet();
requiredInputs.addAll( parserContext1.getInputs().keySet() );
HashMap> variables = (HashMap>) ((Map) parserContext1.getVariables());
if ( localTypes != null ) {
for ( String str : localTypes.keySet() ) {
// we have to do this due to mvel regressions on detecting true local vars
variables.remove( str );
}
}
// MVEL includes direct fields of context object in non-strict mode. so we need to strip those
if ( availableIdentifiers.getThisClass() != null ) {
for ( Iterator it = requiredInputs.iterator(); it.hasNext(); ) {
if ( PropertyTools.getFieldOrAccessor( availableIdentifiers.getThisClass(),
it.next() ) != null ) {
it.remove();
}
}
}
// now, set the required input types and compile again
final ParserContext parserContext2 = new ParserContext( conf );
parserContext2.setStrictTypeEnforcement( true );
parserContext2.setStrongTyping( true );
parserContext2.setInterceptors( dialect.getInterceptors() );
for ( String str : requiredInputs ) {
Class< ? > cls = availableIdentifiers.getDeclrClasses().get( str );
if ( cls != null ) {
parserContext2.addInput( str,
cls );
continue;
}
cls = availableIdentifiers.getGlobals().get( str );
if ( cls != null ) {
parserContext2.addInput( str,
cls );
continue;
}
cls = availableIdentifiers.getOperators().keySet().contains( str ) ? context.getConfiguration().getComponentFactory().getExpressionProcessor().getEvaluatorWrapperClass() : null;
if ( cls != null ) {
parserContext2.addInput( str,
cls );
continue;
}
if ( str.equals( contextIndeifier ) ) {
parserContext2.addInput( contextIndeifier,
kcontextClass );
} else if ( str.equals( "kcontext" ) ) {
parserContext2.addInput( "kcontext",
kcontextClass );
}
if ( str.equals( "rule" ) ) {
parserContext2.addInput( "rule",
Rule.class );
}
if ( localTypes != null ) {
cls = localTypes.get( str );
if ( cls != null ) {
parserContext2.addInput( str,
cls );
}
}
}
if ( availableIdentifiers.getThisClass() != null ) {
parserContext2.addInput( "this",
availableIdentifiers.getThisClass() );
}
boolean typesafe = context.isTypesafe();
try {
returnType = MVEL.analyze( expr,
parserContext2 );
typesafe = true;
} catch ( Exception e ) {
// is this an error, or can we fall back to non-typesafe mode?
if ( typesafe ) {
BaseDescr base = (context instanceof RuleBuildContext) ? ((RuleBuildContext)context).getRuleDescr() : context.getParentDescr();
copyErrorLocation(e, context.getParentDescr());
context.addError( new DescrBuildError( base,
context.getParentDescr(),
null,
"Unable to Analyse Expression " + expr + ":\n" + e.getMessage() ) );
return null;
}
}
if ( typesafe ) {
requiredInputs = new HashSet();
requiredInputs.addAll( parserContext2.getInputs().keySet() );
requiredInputs.addAll( variables.keySet() );
variables = (HashMap>) ((Map) parserContext2.getVariables());
if ( localTypes != null ) {
for ( String str : localTypes.keySet() ) {
// we have to do this due to mvel regressions on detecting true local vars
variables.remove( str );
}
}
}
result = analyze( requiredInputs,
availableIdentifiers );
result.setReturnType( returnType );
result.setMvelVariables( variables );
result.setTypesafe( typesafe );
} else {
result = analyze( (Set) Collections.EMPTY_SET,
availableIdentifiers );
result.setMvelVariables( new HashMap>() );
result.setTypesafe( true );
}
return result;
}
/**
* Analyse an expression.
*
* @throws RecognitionException
* If an error occurs in the parser.
*/
private MVELAnalysisResult analyze(final Set identifiers,
final BoundIdentifiers availableIdentifiers) {
MVELAnalysisResult result = new MVELAnalysisResult();
result.setIdentifiers( identifiers );
final Set notBound = new HashSet( identifiers );
notBound.remove( "this" );
Map> usedDecls = new HashMap>();
Map> usedGlobals = new HashMap>();
Map usedOperators = new HashMap();
for ( Entry> entry : availableIdentifiers.getDeclrClasses().entrySet() ) {
if ( identifiers.contains( entry.getKey() ) ) {
usedDecls.put( entry.getKey(),
entry.getValue() );
notBound.remove( entry.getKey() );
}
}
for ( Entry> entry : availableIdentifiers.getGlobals().entrySet() ) {
if ( identifiers.contains( entry.getKey() ) ) {
usedGlobals.put( entry.getKey(),
entry.getValue() );
notBound.remove( entry.getKey() );
}
}
for ( Map.Entry op : availableIdentifiers.getOperators().entrySet() ) {
if ( identifiers.contains( op.getKey() ) ) {
usedOperators.put( op.getKey(),
op.getValue() );
notBound.remove( op.getKey() );
}
}
result.setBoundIdentifiers( new BoundIdentifiers( usedDecls,
usedGlobals,
usedOperators,
availableIdentifiers.getThisClass() ) );
result.setNotBoundedIdentifiers( notBound );
return result;
}
}
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