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# GroupIntoBatches
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<br>
Batches inputs to a desired batch size.

Batches contain only elements of a single key. Elements are buffered until
`batchSize` number of elements buffered. Then, these elements are output
to the output collection.

Batches contain elements from the same window, so windows are preserved. Batches might contain elements from more than one bundle.

## Examples
See [BEAM-7703](https://issues.apache.org/jira/browse/BEAM-7703) for updates.

## Related transforms 
* [GroupByKey]({{ site.baseurl }}/documentation/transforms/java/aggregation/groupbykey) takes one input collection.