GitHub user cvaliente opened a pull request:
https://github.com/apache/kafka/pull/3581
make Merger extend Aggregator
I suggest that Merger<K,V> should extend Aggregator<K,V,V>.
reason:
Both classes usually do very similar things. A merger takes two sessions
and combines them, an aggregator takes an existing session and aggregates new
values into it.
in some use cases it is actually the same thing, e.g.:
<null, log_event> -> .map() to <session_id,SingletonList<log_event>> ->
.groupByKey().aggregate() to <session_id, List<log_event>>
In this case both merger and aggregator do the same thing: take two lists
and combine them into one.
With the proposed change we could pass the Merger as both the merger and
aggregator to the .aggregate() method and keep our business logic within one
merger class.
Or in other words: The Merger is simply an Aggregator that happens to
aggregate two objects of the same class
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/cvaliente/kafka
KAFKA-5648-make_Merger_extend_Aggregator
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/kafka/pull/3581.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #3581
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commit c20cd6fc7fe5a7403584dc3e04f0b8412fa8db6f
Author: Clemens Valiente <clemens.valie...@trivago.com>
Date: 2017-07-26T15:07:55Z
make Merger extend Aggregator
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