Hi David, Thanks for the inputs.
I did not choose to do so because of following currently identified reasons: 1. lib.util.FilterOperator is actually not an operator instead it is an abstract class - Does not evaluate any expression/condition - Requires an concrete implementation and specifically of satisfiesFilter function 2. No provision for false or error situations - This adds complications for the 'else' part of the DAG or logic - For downstream operators, there is no way to understand if there was an error or it was false On the other hand, I feel, if current FilterOperator abstract class is not being widely used, we can think of phasing this out. Regards, Pradeep A. Dalvi On Tue, May 10, 2016 at 1:20 AM, David Yan <[email protected]> wrote: > Hi, > > It would be useful if you could state why the existing FilterOperator in > Malhar does not satisfy your use case. > The existing operator is at > library/src/main/java/com/datatorrent/lib/util/FilterOperator.java. > > David > > On Sat, May 7, 2016 at 2:34 PM, Pradeep A. Dalvi <[email protected]> wrote: > > > Dear Folks, > > > > We are working on Filter Operator which will allow apex users to filter > > (select/drop) tuples based on the certain condition from incoming stream. > > > > > > Use case: > > > > ------------- > > > > In many cases, not all tuples are of interest for the downstream > operators. > > In such cases, one may want select/filter out tuples to downstream. Also > > one may want to process tuples which did not meet the > condition/expression. > > > > > > Functionality: > > > > ----------------- > > > > 1. Filter operator shall receive POJO as input tuple and emit POJO on > > either of output ports i.e. true and false. As the output ports' name > > signify, when condition is met then the POJO shall be emitted on true > port > > and if condition is not met then that POJO shall be emitted on false > port. > > > > 2. Operator needs condition/expression as a input param. This condition > is > > based on expression language support we already have in Malhar. > > > > > > Please feel free to let me know your thoughts on this. > > > > > > Thanks, > > > > -- > > Pradeep A. Dalvi > > >
