Package com.tangosol.util.aggregator

Class AbstractAsynchronousAggregator<K,V,P,R>

java.lang.Object

com.tangosol.util.AsynchronousAgent<R>

com.tangosol.util.aggregator.AbstractAsynchronousAggregator<K,V,P,R>

Type Parameters:

K - the type of the Map entry keys

V - the type of the Map entry values

P - the type of the intermediate result during the parallel stage

R - the type of the value returned by the StreamingAggregator

All Implemented Interfaces:

FlowControl, InvocableMap.EntryAggregator<K,V,R>, Serializable, Future<R>

Direct Known Subclasses:

AsynchronousAggregator

public abstract class AbstractAsynchronousAggregator<K,V,P,R>
extends AsynchronousAgent<R>
implements InvocableMap.EntryAggregator<K,V,R>

Abstract base class for asynchronous entry aggregators.

Author:

gg/bb 2015.04.02

See Also:

AsynchronousAggregator, Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected InvocableMap.StreamingAggregator<K,V,P,R>	m_aggregator	The underlying aggregator.

Fields inherited from class com.tangosol.util.AsynchronousAgent

m_control, m_iOrderId

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractAsynchronousAggregator(InvocableMap.StreamingAggregator<K,V,P,R> aggregator, int iUnitOrderId)	Construct an AsynchronousAggregator for a given streaming aggregator.

Method Summary

Modifier and Type	Method	Description
R	aggregate(Set<? extends InvocableMap.Entry<? extends K,? extends V>> setEntries)	Not supported.
InvocableMap.StreamingAggregator<K,V,P,R>	getAggregator()	Return the underlying streaming aggregator.
int	getUnitOfOrderId()	Return a unit-of-order id associated with this aggregator.
abstract void	onComplete()	Called after this asynchronous aggregator has been notified about all possible partial results or failures and no more are forthcoming.
abstract void	onException(Throwable eReason)	Called if the operation failed for any reason.
abstract void	onResult(P result)	Called when there is a partial result of the asynchronous execution.

Methods inherited from class com.tangosol.util.AsynchronousAgent

bind, cancel, checkBacklog, complete, completeExceptionally, drainBacklog, flush, get, get, getCompletableFuture, getException, getResult, isCancelled, isCompletedExceptionally, isDone

Methods inherited from class java.lang.Object

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

Field Detail

m_aggregator

protected InvocableMap.StreamingAggregator<K,V,P,R> m_aggregator

The underlying aggregator.

Constructor Detail

AbstractAsynchronousAggregator

protected AbstractAsynchronousAggregator(InvocableMap.StreamingAggregator<K,V,P,R> aggregator,
                                         int iUnitOrderId)

Construct an AsynchronousAggregator for a given streaming aggregator.

Parameters:

aggregator - the underlying streaming aggregator

iUnitOrderId - the unit-of-order id for this aggregator

Method Detail

onResult

public abstract void onResult(P result)

Called when there is a partial result of the asynchronous execution.

For a given request, calls to this method and onException(java.lang.Throwable) may come concurrently.

For ordering guarantees across different aggregator invocations see getUnitOfOrderId().

Note: Overriding implementations of this method must be non-blocking.

Parameters:

result - the partial result holder

onComplete

public abstract void onComplete()

Called after this asynchronous aggregator has been notified about all possible partial results or failures and no more are forthcoming.

As long as this aggregator was submitted to any of InvocableMap's methods, this method is guaranteed to be called once and only once.

Possible call back sequences are:

  cache.aggregate
    ...
    onResult
    onComplete

  cache.aggregate
    ...
    onException
    onComplete

  cache.aggregate
    ...
     onResult
     onException
     onException
     onResult
     onComplete
 

For ordering guarantees across processors see getUnitOfOrderId().

Note:

Overriding implementations of this method must be non-blocking.

If the StreamingAggregator signaled to short-circuit the aggregation while combining partial results, onComplete() could be called before all the results are received.

onException

public abstract void onException(Throwable eReason)

Called if the operation failed for any reason.

For a given request, calls to this method and onResult(P) may come concurrently.

Note: Overriding implementations of this method must be non-blocking.

Parameters:

eReason - the reason of failure

getUnitOfOrderId

public int getUnitOfOrderId()

Return a unit-of-order id associated with this aggregator. By default, the unit-of-order id is assigned to the calling thread's hashCode.

If two consecutive "aggregate" calls made using AsynchronousAggregators with the same order id and involve the same key set, then the corresponding execution and calls to onResult(P) are going to happen in the exact same order.

Note 1: the ordering guarantee is respected between AbstractAsynchronousAggregators and AsynchronousProcessors with the same unit-of-order id;
Note 2: there is no ordering guarantee between asynchronous and synchronous operations.

Overrides:

getUnitOfOrderId in class AsynchronousAgent<R>

Returns:

the order id

See Also:

getUnitOfOrderId(), AbstractAsynchronousProcessor.getUnitOfOrderId()

getAggregator

public InvocableMap.StreamingAggregator<K,V,P,R> getAggregator()

Return the underlying streaming aggregator.

Returns:

the underlying aggregator

aggregate

public R aggregate(Set<? extends InvocableMap.Entry<? extends K,? extends V>> setEntries)

Not supported.

Specified by:

aggregate in interface InvocableMap.EntryAggregator<K,V,P>

Parameters:

setEntries - a Set of read-only InvocableMap.Entry objects to aggregate

Returns:

the aggregated result from processing the entries