package org.drools.rule.builder.dialect.mvel;
import org.drools.base.mvel.MVELCompilationUnit;
import org.drools.base.mvel.MVELObjectExpression;
import org.drools.compiler.BoundIdentifiers;
import org.drools.compiler.DescrBuildError;
import org.drools.reteoo.RuleTerminalNode;
import org.drools.rule.Declaration;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.builder.RuleBuildContext;
import org.drools.spi.KnowledgeHelper;
import java.util.Arrays;
import java.util.Map;
import static org.drools.rule.builder.dialect.DialectUtil.copyErrorLocation;
public class MVELObjectExpressionBuilder {
private MVELObjectExpressionBuilder() { }
public static MVELObjectExpression build( String expression, RuleBuildContext context ) {
boolean typesafe = context.isTypesafe();
// pushing consequence LHS into the stack for variable resolution
context.getBuildStack().push( context.getRule().getLhs() );
try {
// This builder is re-usable in other dialects, so specify by name
MVELDialect dialect = (MVELDialect) context.getDialect( "mvel" );
Map<String, Declaration> decls = context.getDeclarationResolver().getDeclarations(context.getRule());
MVELAnalysisResult analysis = ( MVELAnalysisResult) dialect.analyzeExpression( context,
context.getRuleDescr(),
expression,
new BoundIdentifiers(context.getDeclarationResolver().getDeclarationClasses( decls ),
context.getPackageBuilder().getGlobals() ) );
context.setTypesafe( analysis.isTypesafe() );
final BoundIdentifiers usedIdentifiers = analysis.getBoundIdentifiers();
int i = usedIdentifiers.getDeclrClasses().keySet().size();
Declaration[] previousDeclarations = new Declaration[i];
i = 0;
for ( String id : usedIdentifiers.getDeclrClasses().keySet() ) {
previousDeclarations[i++] = decls.get( id );
}
Arrays.sort(previousDeclarations, RuleTerminalNode.SortDeclarations.instance);
MVELCompilationUnit unit = dialect.getMVELCompilationUnit( expression,
analysis,
previousDeclarations,
null,
null,
context,
"drools",
KnowledgeHelper.class );
MVELObjectExpression expr = new MVELObjectExpression( unit,
dialect.getId() );
MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData( "mvel" );
data.addCompileable( context.getRule(),
expr );
expr.compile( data );
return expr;
} catch ( final Exception e ) {
copyErrorLocation(e, context.getRuleDescr());
context.addError( new DescrBuildError( context.getParentDescr(),
context.getRuleDescr(),
null,
"Unable to build expression : " + e.getMessage() + "'" + expression + "'" ) );
return null;
} finally {
context.setTypesafe( typesafe );
}
}
}