Class Count<T>
java.lang.Object
org.apache.storm.streams.operations.aggregators.Count<T>
- Type Parameters:
T- the value type
- All Implemented Interfaces:
Serializable,CombinerAggregator<T,,Long, Long> Operation
Computes the count of values.
- See Also:
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionUpdates the accumulator by applying the current accumulator with the value.init()The initial value of the accumulator to start with.Merges two accumulators and returns the merged accumulator.Produces a result value out of the accumulator.
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Constructor Details
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Count
public Count()
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Method Details
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init
Description copied from interface:CombinerAggregatorThe initial value of the accumulator to start with.- Specified by:
initin interfaceCombinerAggregator<T,Long, Long> - Returns:
- the initial value of the accumulator
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apply
Description copied from interface:CombinerAggregatorUpdates the accumulator by applying the current accumulator with the value.- Specified by:
applyin interfaceCombinerAggregator<T,Long, Long> - Parameters:
accum- the current accumulatorvalue- the value- Returns:
- the updated accumulator
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merge
Description copied from interface:CombinerAggregatorMerges two accumulators and returns the merged accumulator.- Specified by:
mergein interfaceCombinerAggregator<T,Long, Long> - Parameters:
accum1- the first accumulatoraccum2- the second accumulator- Returns:
- the merged accumulator
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result
Description copied from interface:CombinerAggregatorProduces a result value out of the accumulator.- Specified by:
resultin interfaceCombinerAggregator<T,Long, Long> - Parameters:
accum- the accumulator- Returns:
- the result
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