/*
* Copyright 2007 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.HashSet;
import java.util.Map;
import java.util.Set;
import org.drools.base.accumulators.MVELAccumulatorFunctionExecutor;
import org.drools.base.mvel.MVELAccumulator;
import org.drools.base.mvel.MVELCompilationUnit;
import org.drools.base.mvel.MVELCompileable;
import org.drools.compiler.DescrBuildError;
import org.drools.compiler.Dialect;
import org.drools.lang.descr.AccumulateDescr;
import org.drools.lang.descr.BaseDescr;
import org.drools.rule.Accumulate;
import org.drools.rule.Declaration;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.Pattern;
import org.drools.rule.RuleConditionElement;
import org.drools.rule.builder.AccumulateBuilder;
import org.drools.rule.builder.RuleBuildContext;
import org.drools.rule.builder.RuleConditionBuilder;
import org.drools.runtime.rule.AccumulateFunction;
import org.drools.spi.Accumulator;
/**
* A builder for the java dialect accumulate version
*
* @author etirelli
*/
public class MVELAccumulateBuilder
implements
AccumulateBuilder {
public RuleConditionElement build(final RuleBuildContext context,
final BaseDescr descr) {
return build( context,
descr,
null );
}
@SuppressWarnings("unchecked")
public RuleConditionElement build(final RuleBuildContext context,
final BaseDescr descr,
final Pattern prefixPattern) {
try {
final AccumulateDescr accumDescr = (AccumulateDescr) descr;
if ( !accumDescr.hasValidInput() ) {
return null;
}
final RuleConditionBuilder builder = (RuleConditionBuilder) context.getDialect().getBuilder( accumDescr.getInput().getClass() );
Declaration[] previousDeclarations = (Declaration[]) context.getDeclarationResolver().getDeclarations( context.getRule() ).values().toArray( new Declaration[context.getDeclarationResolver().getDeclarations( context.getRule() ).size()] );
// create source CE
final RuleConditionElement source = builder.build( context,
accumDescr.getInput() );
if ( source == null ) {
return null;
}
MVELDialect dialect = (MVELDialect) context.getDialect();
final Declaration[] sourceDeclArr = (Declaration[]) source.getOuterDeclarations().values().toArray( new Declaration[source.getOuterDeclarations().size()] );
Accumulator accumulator = null;
Declaration[] declarations = null;
if ( accumDescr.isExternalFunction() ) {
// build an external function executor
AccumulateFunction function = context.getConfiguration().getAccumulateFunction( accumDescr.getFunctionIdentifier() );
if( function == null ) {
context.getErrors().add( new DescrBuildError( accumDescr,
context.getRuleDescr(),
null,
"Unknown accumulate function: '"+accumDescr.getFunctionIdentifier()+"' on rule '"+context.getRuleDescr().getName()+"'. All accumulate functions must be registered before building a resource." ) );
return null;
}
Map<String, Class< ? >> declarationsMap = context.getDeclarationResolver().getDeclarationClasses( context.getRule() );
final Dialect.AnalysisResult analysis = dialect.analyzeExpression( context,
accumDescr,
accumDescr.getExpression(),
new Map[]{declarationsMap, context.getPackageBuilder().getGlobals()} );
MVELCompilationUnit unit = dialect.getMVELCompilationUnit( (String) accumDescr.getExpression(),
analysis,
previousDeclarations,
(Declaration[]) source.getOuterDeclarations().values().toArray( new Declaration[source.getOuterDeclarations().size()] ),
null,
context );
accumulator = new MVELAccumulatorFunctionExecutor( unit,
function );
} else {
// it is a custom accumulate
Map<String, Class< ? >> declarationsMap = context.getDeclarationResolver().getDeclarationClasses( context.getRule() );
final MVELAnalysisResult initCodeAnalysis = (MVELAnalysisResult) dialect.analyzeBlock( context,
accumDescr,
accumDescr.getInitCode(),
new Map[]{declarationsMap, context.getPackageBuilder().getGlobals()} );
final MVELAnalysisResult actionCodeAnalysis = (MVELAnalysisResult) dialect.analyzeBlock( context,
accumDescr,
null,
accumDescr.getActionCode(),
new Map[]{declarationsMap, context.getPackageBuilder().getGlobals()},
initCodeAnalysis.getMvelVariables() );
final MVELAnalysisResult resultCodeAnalysis = (MVELAnalysisResult) dialect.analyzeExpression( context,
accumDescr,
accumDescr.getResultCode(),
new Map[]{declarationsMap, context.getPackageBuilder().getGlobals()},
initCodeAnalysis.getMvelVariables() );
Dialect.AnalysisResult reverseCodeAnalysis = null;
if ( accumDescr.getReverseCode() != null ) {
reverseCodeAnalysis = dialect.analyzeBlock( context,
accumDescr,
null,
accumDescr.getActionCode(),
new Map[]{declarationsMap, context.getPackageBuilder().getGlobals()},
initCodeAnalysis.getMvelVariables() );
}
MVELCompilationUnit initUnit = dialect.getMVELCompilationUnit( (String) accumDescr.getInitCode(),
initCodeAnalysis,
previousDeclarations,
(Declaration[]) source.getOuterDeclarations().values().toArray( new Declaration[source.getOuterDeclarations().size()] ),
null,
context );
MVELCompilationUnit actionUnit = dialect.getMVELCompilationUnit( (String) accumDescr.getActionCode(),
actionCodeAnalysis,
previousDeclarations,
(Declaration[]) source.getOuterDeclarations().values().toArray( new Declaration[source.getOuterDeclarations().size()] ),
initCodeAnalysis.getMvelVariables(),
context );
MVELCompilationUnit reverseUnit = null;
if ( accumDescr.getReverseCode() != null ) {
reverseUnit = dialect.getMVELCompilationUnit( (String) accumDescr.getReverseCode(),
reverseCodeAnalysis,
previousDeclarations,
(Declaration[]) source.getOuterDeclarations().values().toArray( new Declaration[source.getOuterDeclarations().size()] ),
initCodeAnalysis.getMvelVariables(),
context );
}
MVELCompilationUnit resultUnit = dialect.getMVELCompilationUnit( (String) accumDescr.getResultCode(),
resultCodeAnalysis,
previousDeclarations,
(Declaration[]) source.getOuterDeclarations().values().toArray( new Declaration[source.getOuterDeclarations().size()] ),
initCodeAnalysis.getMvelVariables(),
context );
if ( reverseUnit != null ) {
Set<String> shadow = new HashSet<String>( source.getOuterDeclarations().keySet() );
shadow.retainAll( reverseCodeAnalysis.getNotBoundedIdentifiers() );
shadow.addAll( reverseCodeAnalysis.getBoundIdentifiers()[0] );
String[] shadowVars = (String[]) shadow.toArray( new String[shadow.size()] );
actionUnit.setShadowIdentifiers( shadowVars );
reverseUnit.setShadowIdentifiers( shadowVars );
}
accumulator = new MVELAccumulator( initUnit,
actionUnit,
reverseUnit,
resultUnit );
}
final Accumulate accumulate = new Accumulate( source,
declarations,
sourceDeclArr,
new Accumulator[] { accumulator } );
MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData( "mvel" );
data.addCompileable( accumulate,
(MVELCompileable) accumulator );
((MVELCompileable) accumulator).compile( context.getPackageBuilder().getRootClassLoader() );
return accumulate;
} catch ( Exception e ) {
context.getErrors().add( new DescrBuildError( context.getParentDescr(),
descr,
e,
"Unable to build expression for 'accumulate' : " + e.getMessage() ) );
return null;
}
}
}