InputT - the type of input valuesOutputT - the type of output valuespublic interface Aggregator<InputT,OutputT>
Aggregator<InputT> enables monitoring of values of type InputT,
to be combined across all bundles.
Aggregators are created by calling DoFn.createAggregator,
typically from the DoFn constructor. Elements can be added to the
Aggregator by calling addValue(InputT).
Aggregators are visible in the monitoring UI, when the pipeline is run using DataflowRunner or BlockingDataflowRunner, along with their current value. Aggregators may not become visible until the system begins executing the ParDo transform that created them and/or their initial value is changed.
Example:
class MyDoFn extends DoFn{ private Aggregator myAggregator; public MyDoFn() { myAggregator = createAggregator("myAggregator", new Sum.SumIntegerFn()); }
| Modifier and Type | Method and Description |
|---|---|
void |
addValue(InputT value)
Adds a new value into the Aggregator.
|
Combine.CombineFn<InputT,?,OutputT> |
getCombineFn()
Returns the
Combine.CombineFn, which combines input elements in the
aggregator. |
String |
getName()
Returns the name of the Aggregator.
|
void addValue(InputT value)
String getName()
Combine.CombineFn<InputT,?,OutputT> getCombineFn()
Combine.CombineFn, which combines input elements in the
aggregator.