/*
* 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.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import org.drools.base.accumulators.AccumulateFunction;
import org.drools.base.accumulators.MVELAccumulatorFunctionExecutor;
import org.drools.base.mvel.DroolsMVELFactory;
import org.drools.base.mvel.MVELAccumulator;
import org.drools.compiler.Dialect;
import org.drools.lang.descr.AccumulateDescr;
import org.drools.lang.descr.BaseDescr;
import org.drools.lang.descr.PatternDescr;
import org.drools.rule.Accumulate;
import org.drools.rule.Declaration;
import org.drools.rule.Pattern;
import org.drools.rule.RuleConditionElement;
import org.drools.rule.builder.AccumulateBuilder;
import org.drools.rule.builder.PatternBuilder;
import org.drools.rule.builder.RuleBuildContext;
import org.drools.spi.Accumulator;
import org.mvel.MVEL;
/**
* 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 );
}
public RuleConditionElement build(final RuleBuildContext context,
final BaseDescr descr,
final Pattern prefixPattern) {
final AccumulateDescr accumDescr = (AccumulateDescr) descr;
final PatternBuilder patternBuilder = (PatternBuilder) context.getDialect().getBuilder( PatternDescr.class );
// create source pattern
final Pattern sourcePattern = (Pattern) patternBuilder.build( context,
accumDescr.getInputPattern() );
if ( sourcePattern == null ) {
return null;
}
MVELDialect dialect = (MVELDialect) context.getDialect();
final Declaration[] sourceDeclArr = (Declaration[]) sourcePattern.getOuterDeclarations().values().toArray( new Declaration[0] );
final DroolsMVELFactory factory = new DroolsMVELFactory( context.getDeclarationResolver().getDeclarations(),
sourcePattern.getOuterDeclarations(),
context.getPkg().getGlobals() );
factory.setNextFactory( dialect.getStaticMethodImportResolverFactory() );
Accumulator accumulator = null;
Declaration[] declarations = null;
if ( accumDescr.isExternalFunction() ) {
// build an external function executor
final Dialect.AnalysisResult analysis = dialect.analyzeExpression( context,
accumDescr,
accumDescr.getExpression() );
int size = analysis.getBoundIdentifiers()[0].size();
declarations = new Declaration[size];
for ( int i = 0; i < size; i++ ) {
declarations[i] = context.getDeclarationResolver().getDeclaration( (String) analysis.getBoundIdentifiers()[0].get( i ) );
}
final Serializable expression = dialect.compile( (String) accumDescr.getExpression(),
analysis,
null,
sourcePattern.getOuterDeclarations(),
context );
AccumulateFunction function = context.getConfiguration().getAccumulateFunction( accumDescr.getFunctionIdentifier() );
accumulator = new MVELAccumulatorFunctionExecutor( factory,
expression,
function );
} else {
// it is a custom accumulate
final MVELAnalysisResult initCodeAnalysis = (MVELAnalysisResult) dialect.analyzeBlock( context,
accumDescr,
accumDescr.getInitCode() );
final MVELAnalysisResult actionCodeAnalysis = (MVELAnalysisResult) dialect.analyzeBlock( context,
accumDescr,
null,
accumDescr.getActionCode(),
initCodeAnalysis.getMvelVariables() );
actionCodeAnalysis.setMvelVariables( initCodeAnalysis.getMvelVariables() );
final MVELAnalysisResult resultCodeAnalysis = (MVELAnalysisResult) dialect.analyzeExpression( context,
accumDescr,
accumDescr.getResultCode(),
initCodeAnalysis.getMvelVariables() );
resultCodeAnalysis.setMvelVariables( initCodeAnalysis.getMvelVariables() );
final List requiredDeclarations = new ArrayList( initCodeAnalysis.getBoundIdentifiers()[0] );
requiredDeclarations.addAll( actionCodeAnalysis.getBoundIdentifiers()[0] );
requiredDeclarations.addAll( resultCodeAnalysis.getBoundIdentifiers()[0] );
if ( accumDescr.getReverseCode() != null ) {
final Dialect.AnalysisResult reverseCodeAnalysis = context.getDialect().analyzeBlock( context,
accumDescr,
accumDescr.getActionCode() );
requiredDeclarations.addAll( reverseCodeAnalysis.getBoundIdentifiers()[0] );
}
declarations = new Declaration[requiredDeclarations.size()];
for ( int i = 0, size = requiredDeclarations.size(); i < size; i++ ) {
declarations[i] = context.getDeclarationResolver().getDeclaration( (String) requiredDeclarations.get( i ) );
}
final Serializable init = dialect.compile( (String) accumDescr.getInitCode(),
initCodeAnalysis,
null,
sourcePattern.getOuterDeclarations(),
context );
final Serializable action = dialect.compile( (String) accumDescr.getActionCode(),
actionCodeAnalysis,
null,
sourcePattern.getOuterDeclarations(),
context );
Serializable reverse = null;
if ( accumDescr.getReverseCode() != null ) {
reverse = dialect.compile( (String) accumDescr.getReverseCode(),
resultCodeAnalysis,
null,
sourcePattern.getOuterDeclarations(),
context );
}
final Serializable result = dialect.compile( (String) accumDescr.getResultCode(),
resultCodeAnalysis,
null,
sourcePattern.getOuterDeclarations(),
context );
accumulator = new MVELAccumulator( factory,
init,
action,
reverse,
result );
}
final Accumulate accumulate = new Accumulate( sourcePattern,
declarations,
sourceDeclArr,
accumulator );
return accumulate;
}
}