Class ReduceCombineDriver<T>
java.lang.Object
org.apache.flink.runtime.operators.ReduceCombineDriver<T>
- Type Parameters:
T- The data type consumed and produced by the combiner.
- All Implemented Interfaces:
Driver<org.apache.flink.api.common.functions.ReduceFunction<T>,T>
public class ReduceCombineDriver<T>
extends Object
implements Driver<org.apache.flink.api.common.functions.ReduceFunction<T>,T>
Combine operator for Reduce functions, standalone (not chained). Sorts and groups and reduces
data, but never spills the sort. May produce multiple partially aggregated groups.
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoidcancel()This method is invoked when the driver must aborted in mid processing.voidcleanup()This method is invoked in any case (clean termination and exception) at the end of the tasks operation.intGets the number of comparators required for this driver.intGets the number of inputs that the task has.Gets the class of the stub type that is run by this task.voidprepare()This method is called before the user code is opened.voidrun()The main operation method of the task.voidsetup(TaskContext<org.apache.flink.api.common.functions.ReduceFunction<T>, T> context)
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Constructor Details
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ReduceCombineDriver
public ReduceCombineDriver()
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Method Details
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setup
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getNumberOfInputs
public int getNumberOfInputs()Description copied from interface:DriverGets the number of inputs that the task has.- Specified by:
getNumberOfInputsin interfaceDriver<org.apache.flink.api.common.functions.ReduceFunction<T>,T> - Returns:
- The number of inputs.
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getStubType
Description copied from interface:DriverGets the class of the stub type that is run by this task. For example, a MapTask should returnMapFunction.class.- Specified by:
getStubTypein interfaceDriver<org.apache.flink.api.common.functions.ReduceFunction<T>,T> - Returns:
- The class of the stub type run by the task.
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getNumberOfDriverComparators
public int getNumberOfDriverComparators()Description copied from interface:DriverGets the number of comparators required for this driver.- Specified by:
getNumberOfDriverComparatorsin interfaceDriver<org.apache.flink.api.common.functions.ReduceFunction<T>,T> - Returns:
- The number of comparators required for this driver.
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prepare
Description copied from interface:DriverThis method is called before the user code is opened. An exception thrown by this method signals failure of the task. -
run
Description copied from interface:DriverThe main operation method of the task. It should call the user code with the data subsets until the input is depleted.- Specified by:
runin interfaceDriver<org.apache.flink.api.common.functions.ReduceFunction<T>,T> - Throws:
Exception- Any exception thrown by this method signals task failure. Because exceptions in the user code typically signal situations where this instance in unable to proceed, exceptions from the user code should be forwarded.
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cleanup
public void cleanup()Description copied from interface:DriverThis method is invoked in any case (clean termination and exception) at the end of the tasks operation. -
cancel
public void cancel()Description copied from interface:DriverThis method is invoked when the driver must aborted in mid processing. It is invoked asynchronously by a different thread.
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