@Internal public class OperatorSubtaskStateReducer extends RichGroupReduceFunction<TaggedOperatorSubtaskState,OperatorState>
OperatorSubtaskState
's for a particular operator into a
single OperatorState
.Constructor and Description |
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OperatorSubtaskStateReducer(OperatorID operatorID,
int maxParallelism) |
Modifier and Type | Method and Description |
---|---|
void |
open(OpenContext openContext)
Initialization method for the function.
|
void |
reduce(Iterable<TaggedOperatorSubtaskState> values,
Collector<OperatorState> out)
The reduce method.
|
close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext
public OperatorSubtaskStateReducer(OperatorID operatorID, int maxParallelism)
public void open(OpenContext openContext) throws Exception
RichFunction
The openContext object passed to the function can be used for configuration and initialization. The openContext contains some necessary information that were configured on the function in the program composition.
public class MyFilter extends RichFilterFunction<String> {
private String searchString;
public void open(OpenContext openContext) {
// initialize the value of searchString
}
public boolean filter(String value) {
return value.equals(searchString);
}
}
By default, this method does nothing.
1. If you implement open(OpenContext openContext)
, the open(OpenContext
openContext)
will be invoked and the open(Configuration parameters)
won't be
invoked. 2. If you don't implement open(OpenContext openContext)
, the open(Configuration parameters)
will be invoked in the default implementation of the open(OpenContext openContext)
.
openContext
- The context containing information about the context in which the function
is opened.Exception
- Implementations may forward exceptions, which are caught by the runtime.
When the runtime catches an exception, it aborts the task and lets the fail-over logic
decide whether to retry the task execution.public void reduce(Iterable<TaggedOperatorSubtaskState> values, Collector<OperatorState> out)
GroupReduceFunction
reduce
in interface GroupReduceFunction<TaggedOperatorSubtaskState,OperatorState>
reduce
in class RichGroupReduceFunction<TaggedOperatorSubtaskState,OperatorState>
values
- All records that belong to the given input key.out
- The collector to hand results to.Copyright © 2014–2023 The Apache Software Foundation. All rights reserved.