How to use LoadMetadata setPartitionFilter(Expression partitionFilter)

[Gerrit Jansen van Vuuren <gv...@specificmedia.com>]

 Hi,

I'm trying to implement the partition keys and filter methods of the LoadMetadata interface for the HiveColumnarLoader function. 
But have one question as to how would I use the Expression parameter in the setPartitionFilter(Expression) method.

I know this contains the filter expressions that are applied against partition keys in my Loader, but is there an 'Executor' 
or class that evaluates this expression? 

I was thinking of using some kind of EL library but wanted to make sure I'm not re-implementing something that is already there.

Thanks, 
 Gerrit