Package com.scaleoutsoftware.modules.abstractions

Class ReduceApiProcessor<O,R>

java.lang.Object

com.scaleoutsoftware.modules.abstractions.ReduceApiProcessor<O,R>

Type Parameters:

O - the SOSS object type.

R - the result object type.

public abstract class ReduceApiProcessor<O,R>
extends Object

A parallel operation that returns a result.

Constructor Summary

Constructors

Constructor	Description
ReduceApiProcessor()	Instantiate a new ReduceApiProcessor.

Method Summary

Modifier and Type	Method	Description
abstract R	accumulatorFactory()	Constructs an instance of a ReduceApiProcessor that will be passed to each invocation of evaluate(ApiProcessingContext, Object, Object, byte[]).
abstract R	deserializeResult(byte[] value)	Deserializes a result object into a ReduceApiProcessor.
abstract EvalResult<R>	evaluate(ApiProcessingContext<O> context, R accumulator, O sossObject, byte[] parameter)	Evaluates a SOSS object, merges the result into the parameter ReduceApiProcessor accumulator, and returns the accumulated result.
abstract R	reduce(R result1, R result2)	Reduces two results into one and returns the reduced result.
abstract byte[]	serializeResult(R value)	Serializes a ReduceApiProcessor into a byte[].

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ReduceApiProcessor

public ReduceApiProcessor()

Instantiate a new ReduceApiProcessor.

Method Details

accumulatorFactory

public abstract R accumulatorFactory()

Constructs an instance of a ReduceApiProcessor that will be passed to each invocation of evaluate(ApiProcessingContext, Object, Object, byte[]).

Returns:

an instance of ReduceApiProcessor.

evaluate

public abstract EvalResult<R> evaluate(ApiProcessingContext<O> context,
 R accumulator,
 O sossObject,
 byte[] parameter)

Evaluates a SOSS object, merges the result into the parameter ReduceApiProcessor accumulator, and returns the accumulated result.

Parameters:

context - the ApiProcessingContext.

accumulator - the accumulator of previous results.

sossObject - the SOSS object.

parameter - the serialized parameter object, or null.

Returns:

a EvalResult with the accumulator with the new result merged in and a ProcessingResult. Use ProcessingResult.DoUpdate if the object was mutated, ProcessingResult.NoUpdate if the object was not-mutated, or ProcessingResult.Remove if the object should be deleted from ScaleOut.

reduce

public abstract R reduce(R result1,
 R result2)

Reduces two results into one and returns the reduced result.

Parameters:

result1 - the first result.

result2 - the second result.

Returns:

the merged result.

deserializeResult

public abstract R deserializeResult(byte[] value)

Deserializes a result object into a ReduceApiProcessor.

Parameters:

value - the serialized result value.

Returns:

an instance of ReduceApiProcessor hydrated from the parameter value.

serializeResult

public abstract byte[] serializeResult(R value)

Serializes a ReduceApiProcessor into a byte[].

Parameters:

value - the result object to serialize.

Returns:

the serialized result.