Re: [rules-dev] Compiling drools-5 to .NET -- issue with ClassLoaders

Hello, I've been trying to compile the latest version of drools to .NET for a few days now. However, due to the classloaders structure, the classes in the org.drools.base.extractors.* are not found by the classloader, and the execution stops with a NoClassDefFoundError for classes in that package. Here's some details about the setup: Drools version: 5.0.1 IKVM Version: 0.40.0.1 I have successfully compiled all the required libraries into a DLL using IKVM, and a simple rule (containing a null LHS) runs successfully, all the classes are found, and the rule engine produces the correct output. However, when I add a condition into the LHS, it fails because it can't find one of the classes in /org.drools.base.extractors..*Reader/ A sample rule I am using is: """ package package import rules.Customer import rules.VoucherSeries rule "everything free for Krishna"        when                $c : Customer( firstname == "Krishna" )        then                VoucherSeries fact0 = new VoucherSeries();                fact0.setSeriesCode( "FREE" );                insert(fact0 ); end """ I have verified that all the classes are present in the classloader I am passing to the KnowledgeBuilderConfiguration. In fact, I also tried creating a MapBasedClassLoader that contains all the missing classes so that they can be easily found using fastFindClass. In the code listing below, both klass and klass2 resolve to the correct class objects. """            java.util.Properties p = new java.util.Properties();            p.put("drools.dialect.java.compiler", "JANINO");            java.lang.ClassLoader cl = java.lang.Class.forName("org.drools.base.extractors.BaseLongClassFieldReader").getClassLoader();            org.drools.rule.CompositeClassLoader compositeClassLoader = new org.drools.rule.CompositeClassLoader(cl);            org.drools.rule.MapBackedClassLoader mbcl = getMapBackedClassLoader(cl);            compositeClassLoader.addClassLoader(mbcl);            java.lang.Class klass = compositeClassLoader.fastFindClass("rules.Customer");            java.lang.Class klass2 = compositeClassLoader.fastFindClass("org.drools.base.extractors.BaseObjectClassFieldReader");            java.lang.ClassLoader finalClassLoader = compositeClassLoader;            org.drools.builder.KnowledgeBuilderConfiguration kbc = org.drools.builder.KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration(p, finalClassLoader); """ However, adding the DRL / PKG file, it fails with the exception: java.lang.NoClassDefFoundError was caught  Message="org.drools.base.extractors.BaseObjectClassFieldReader"  Source="IKVM.Runtime"  StackTrace:       at IKVM.NativeCode.java.lang.ClassLoader.defineClass1(Object thisClassLoader, String name, Byte[] b, Int32 off, Int32 len, Object pd, String source)       at java.lang.ClassLoader.defineClass1(String , Byte[] , Int32 , Int32 , ProtectionDomain , String )       at java.lang.ClassLoader.defineClass(String name, Byte[] b, Int32 off, Int32 len, ProtectionDomain protectionDomain)       at org.drools.base.ClassFieldAccessorCache.ByteArrayClassLoader.defineClass(String name, Byte[] bytes, ProtectionDomain domain)       at org.drools.base.ClassFieldAccessorFactory.getClassFieldReader(Class clazz, String fieldName, CacheEntry cache)       at org.drools.base.ClassFieldAccessorCache.CacheEntry.getReadAccessor(AccessorKey key, Class cls)       at org.drools.base.ClassFieldAccessorCache.getReadAcessor(ClassFieldReader reader)       at org.drools.base.ClassFieldAccessorStore.wire(ClassFieldReader reader)       at org.drools.base.ClassFieldAccessorStore.getReader(String className, String fieldName, AcceptsReadAccessor target, AccessorType accessorType)       at org.drools.base.ClassFieldAccessorStore.getReader(String className, String fieldName, AcceptsReadAccessor target)       at org.drools.rule.builder.PatternBuilder.getFieldReadAccessor(RuleBuildContext context, BaseDescr descr, ObjectType objectType, String fieldName, AcceptsReadAccessor target, Boolean reportError)       at org.drools.rule.builder.PatternBuilder.build(RuleBuildContext , Pattern , FieldConstraintDescr , AbstractCompositeConstraint )       at org.drools.rule.builder.PatternBuilder.buildConstraint(RuleBuildContext , Pattern , Object , AbstractCompositeConstraint )       at org.drools.rule.builder.PatternBuilder.build(RuleBuildContext context, BaseDescr descr, Pattern prefixPattern)       at org.drools.rule.builder.PatternBuilder.build(RuleBuildContext context, BaseDescr descr)       at org.drools.rule.builder.GroupElementBuilder.build(RuleBuildContext context, BaseDescr descr, Pattern prefixPattern)       at org.drools.rule.builder.RuleBuilder.build(RuleBuildContext context)       at org.drools.compiler.PackageBuilder.addRule(RuleDescr )       at org.drools.compiler.PackageBuilder.addPackage(PackageDescr packageDescr)       at org.drools.compiler.PackageBuilder.addPackageFromDrl(Resource resource)       at org.drools.compiler.PackageBuilder.addKnowledgeResource(Resource resource, ResourceType type, ResourceConfiguration configuration)       at org.drools.builder.impl.KnowledgeBuilderImpl.add(Resource resource, ResourceType type)       at Capillary.Client.RulesEngine.RuleManager.ReadRules(String filename) in D:\coderoot\module\DataEntryClient-DVS\SubProjects\RulesEngine\RuleManager.cs:line 116  InnerException: I saw the code at org/drools/base/ClassFieldAccessorCache.java, and it seems me that the Reader class for the particular type is being defined in situ using a byte[] array, but I am unable to understand why it can't load the class at that point. Can anybody with a better idea of the drools classloading structure guide me here? Also, is the drools.NET project active now? I would post all the steps I took for posterity. Thanks and Regards, Krishna. -- http://kpowerinfinity.wordpress.com http://www.linkedin.com/in/kpowerinfinity _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev