Correlation condition in Aggregate Pattern

Question

Hi Team,
Just Started the Aggregate Pattern and
My Requirement is to collect the 3 messages of Pencils based on their color(should be same for three messages)
Below is My pattern:
Start:
I have initialized the Counter to zero
CurrentPencilID is of type string(what should we initialize here?)
Numberof Pencils is of type integer(what should we initialize here?))
Mapping
I have Incremented the Loop and mapped the outputs.
Exclusive choice
Here I have given the condition for the loop if counter reaches the count 3 it will send the message and end the activity.
Else
Intermediate Step.
Here the incoming message should match the correlation field and But I am unable to do so.
Please help me out for this condition evaluation.
As it should collect messages of three Blue Pencils and aggregate all three messages and send to the target.
Regards,
Novveen

Answer 1

Hi Novveen,
from what i understand, the difficulty is what to initialize CurrentPencilID and Numberof Pencils. I assume CurrentPencilID is storing the color of pencil. (Please correct me if its not so)
perhaps you can try something like below condition in correlation. Below condition should return true for first message i.e. when counter = 0 and accept whatever color is supplied. In IntermediateMesasge output, you should map the first incoming color into CurrentPencilID. So first pass will initialize color id. Also you will increment counter.
     IF(Counter=0,true,IncomingMessage/Color=CurrentPencilID)
For next passes, as counter is non-zero, the result of IncomingMessage/Color is evaluated against initial color ID i.e. CurrentPencilID (IncomingMessage/Color=CurrentPencilID) and returned.
For each successful return, NumberOfPencils is incremented (little doubt - why its used, isnt counter doing same ? )
-Abhijeet