Aggregating values from an Aggregation Extension Point

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Version: Mars.1 Release (4.5.1) Build id: 20150924-1200
 
I have built an aggregation extension point that is an extension of the IAggregationFactory interface to provide the difference between the current row value and previous row values. It seems to work just fine and Iâ€™ve been able to bring it into BIRT as a plugin. However I get some strange behavior when I use it in a table with groups. Specifically I canâ€™t get aggregation to work in the column where I use or reference the output of the aggregation extension point. The following one group of the resultant table (see PDF):
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kevindwatkins

As a follow-up, I wrote another aggregation extension point of the summary type that counts the number of times the onRow method in the accumulator object is invoked. It shows that for the columns that use the values from a RUNNING_AGGR type aggregation, the SUMMARY_AGGR aggregation's onRow method is only invoked once (presumably â€‹on the first row) per group table.

kevindwatkins

Upon further experimentation, I have determined that the problem I'm describing is resulting from strange behavior when an Aggregation Extension Point is used to aggregate on a group (as opposed to the table). I have created a simple example that illustrates this behavior and will open a thread named "Grouping Anomaly with Aggregation Extension Points" to discuss it.