Request for C++ ExtractorProcessor code snippets

Question

Hi,
Does anyone have any C++ code snippets of using the ExtractorProcessor?
I'm trying to implement an ExtractorProcessor in C++ - I have created a ValueExtractor and I can create the ExtractorProcessor from that, but the compiler gives me an error when I try to invoke it
Error     6     error C2665: 'coherence::lang::TypedHandle<T>::TypedHandle' : none of the 4 overloads could convert all the argument types     c:\dcs_systems\test\trunk\ThirdParty\Components\coherence_3_7_1_x86\include\coherence\lang\TypedHolder.hpp     205     D3ContextCache
This is my call
int CacheD3ContextRepository::getD3ContextState(int call_id) const
     Integer32::View vKey = Integer32::create(call_id);
     ValueExtractor::View vStateExtractor =
          COH_MANAGED_BOX_EXTRACTOR(Integer32::View, CacheD3Context, getState);
     ExtractorProcessor::Handle vStateFetcher = ExtractorProcessor::create(vStateExtractor);
     Integer32::View vState;// = _cache->invoke(vKey, vStateFetcher);
     return *vState;
Essentially I have CacheD3Context object but I don't want to read back the whole object just the state field.
I have been told that something called a 'ReducerAggregator' is a better way of doing this but I haven't been able to find this yet.
Thanks
Joe
Edited by: 841803 on 09-Apr-2013 00:55

Answer 1

Hi Joe,
The invoke method returns an Object::Holder, which will need to be cast to the extracted type:
int CacheD3ContextRepository::getD3ContextState(int call_id) const
    Integer32::View              vKey            = Integer32::create(call_id);
    ValueExtractor::View         vStateExtractor = COH_MANAGED_BOX_EXTRACTOR(Integer32::View, CacheD3Context, getState);
    ExtractorProcessor::Handle   vStateFetcher   = ExtractorProcessor::create(vStateExtractor);
    Integer32::View              vState          = cast<Integer32::View>(_cache->invoke(vKey, vStateFetcher));
    return *vState;
    }Note that when the extraction will be performed server side, the above extractor will be evaluated as a ReflectionExtractor in java, and will invoke the java getState method. This implies you'll need the CacheD3Context (or equivalent) java class in the classpath of your cache servers. If this is not an option then have a look at PofExtractor.
thanks,
Mark
Oracle Coherence