/*
* Copyright 2006 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.java;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import org.drools.compiler.Dialect;
import org.drools.compiler.RuleError;
import org.drools.lang.descr.RuleDescr;
import org.drools.rule.Declaration;
import org.drools.rule.builder.ConsequenceBuilder;
import org.drools.rule.builder.RuleBuildContext;
import org.drools.rule.builder.dialect.java.parser.JavaModifyBlockDescr;
import org.drools.rule.builder.dialect.mvel.MVELDialect;
import org.drools.spi.PatternExtractor;
import org.mvel.ExecutableStatement;
/**
* @author etirelli
*
*/
public class JavaConsequenceBuilder extends AbstractJavaBuilder
implements
ConsequenceBuilder {
/* (non-Javadoc)
* @see org.drools.semantics.java.builder.ConsequenceBuilder#buildConsequence(org.drools.semantics.java.builder.BuildContext, org.drools.semantics.java.builder.BuildUtils, org.drools.lang.descr.RuleDescr)
*/
public void build(final RuleBuildContext context) {
// pushing consequence LHS into the stack for variable resolution
context.getBuildStack().push( context.getRule().getLhs() );
final String className = "consequence";
final RuleDescr ruleDescr = context.getRuleDescr();
Dialect.AnalysisResult analysis = context.getDialect().analyzeBlock( context,
ruleDescr,
(String) ruleDescr.getConsequence() );
if ( analysis == null ) {
// not possible to get the analysis results
return;
}
String fixedConsequence = this.fixModifyBlocks( context,
(JavaAnalysisResult) analysis,
(String) ruleDescr.getConsequence() );
if ( fixedConsequence == null ) {
// not possible to rewrite the modify blocks
return;
}
fixedConsequence = ((JavaDialect) context.getDialect()).getKnowledgeHelperFixer().fix( fixedConsequence );
final List[] usedIdentifiers = analysis.getBoundIdentifiers();
final Declaration[] declarations = new Declaration[usedIdentifiers[0].size()];
for ( int i = 0, size = usedIdentifiers[0].size(); i < size; i++ ) {
declarations[i] = context.getDeclarationResolver().getDeclaration( (String) usedIdentifiers[0].get( i ) );
}
final Map map = createVariableContext( className,
null,
context,
declarations,
null,
(String[]) usedIdentifiers[1].toArray( new String[usedIdentifiers[1].size()] ) );
map.put( "text",
fixedConsequence );
// Must use the rule declarations, so we use the same order as used in the generated invoker
final List list = Arrays.asList( context.getRule().getDeclarations() );
//final int[] indexes = new int[declarations.length];
final Integer[] indexes = new Integer[declarations.length];
final Boolean[] notPatterns = new Boolean[declarations.length];
for ( int i = 0, length = declarations.length; i < length; i++ ) {
indexes[i] = new Integer( list.indexOf( declarations[i] ) );
notPatterns[i] = (declarations[i].getExtractor() instanceof PatternExtractor) ? new Boolean( false ) : new Boolean( true );
if ( (indexes[i]).intValue() == -1 ) {
context.getErrors().add( new RuleError( context.getRule(),
ruleDescr,
null,
"Internal Error : Unable to find declaration in list while generating the consequence invoker" ) );
}
}
map.put( "indexes",
indexes );
map.put( "notPatterns",
notPatterns );
generatTemplates( "consequenceMethod",
"consequenceInvoker",
context,
className,
map,
context.getRule(),
ruleDescr );
// popping Rule.getLHS() from the build stack
context.getBuildStack().pop();
}
protected String fixModifyBlocks(final RuleBuildContext context,
final JavaAnalysisResult analysis,
final String originalCode) {
MVELDialect mvel = (MVELDialect) context.getDialect( "mvel" );
TreeSet blocks = new TreeSet( new Comparator() {
public int compare(Object o1,
Object o2) {
JavaModifyBlockDescr d1 = (JavaModifyBlockDescr) o1;
JavaModifyBlockDescr d2 = (JavaModifyBlockDescr) o2;
return d1.getStart() - d2.getStart();
}
} );
for ( Iterator it = analysis.getModifyBlocks().iterator(); it.hasNext(); ) {
blocks.add( it.next() );
}
StringBuffer consequence = new StringBuffer();
int lastAdded = 0;
for ( Iterator it = blocks.iterator(); it.hasNext(); ) {
JavaModifyBlockDescr d = (JavaModifyBlockDescr) it.next();
// adding chunk
consequence.append( originalCode.substring( lastAdded,
d.getStart() - 1 ) );
lastAdded = d.getEnd();
Dialect.AnalysisResult mvelAnalysis = mvel.analyzeBlock( context,
context.getRuleDescr(),
mvel.getInterceptors(),
d.getModifyExpression(),
null );
final ExecutableStatement expr = (ExecutableStatement) mvel.compile( d.getModifyExpression(),
mvelAnalysis,
mvel.getInterceptors(),
null,
null,
context );
Class ret = expr.getKnownEgressType();
if ( ret == null ) {
// not possible to evaluate expression return value
context.getErrors().add( new RuleError( context.getRule(),
context.getRuleDescr(),
originalCode,
"Unable to determine the resulting type of the expression: " + d.getModifyExpression() + "\n" ) );
return null;
}
// adding modify expression
consequence.append( ret.getName() );
consequence.append( " __obj__ = (" );
consequence.append( ret.getName() );
consequence.append( ") " );
consequence.append( d.getModifyExpression() );
consequence.append( ";\n" );
// adding the modifyRetract call:
consequence.append( "modifyRetract( __obj__ );\n" );
// adding each of the expressions:
for ( Iterator exprIt = d.getExpressions().iterator(); exprIt.hasNext(); ) {
consequence.append( "__obj__." );
consequence.append( exprIt.next() );
consequence.append( ";\n" );
}
// adding the modifyInsert call:
consequence.append( "modifyInsert( __obj__ );" );
}
consequence.append( originalCode.substring( lastAdded ) );
return consequence.toString();
}
}