Package cz.o2.proxima.direct.core

Interface LogObserver<OffsetT extends java.io.Serializable,ContextT extends LogObserver.OnNextContext<OffsetT>>

All Known Subinterfaces:

BatchLogObserver, CommitLogObserver

All Known Implementing Classes:

BatchLogReaders.ForwardingBatchLogObserver, CommitLogObservers.ForwardingObserver, OffsetTrackingBatchLogReader.OffsetTrackingBatchLogObserver, ThreadPooledObserver, TransactionLogObserver, TransformationObserver, TransformationObserver.Contextual, TransformationObserver.NonContextual

@Stable
public interface LogObserver<OffsetT extends java.io.Serializable,ContextT extends LogObserver.OnNextContext<OffsetT>>

Base interface for bulk and online observers.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	LogObserver.OnNextContext<OffsetT extends java.io.Serializable>	Context passed to onNext(cz.o2.proxima.core.storage.StreamElement, ContextT).

Method Summary

Modifier and Type	Method	Description
default void	onCancelled()	Notify that the processing has been canceled.
default void	onCompleted()	Notify that the processing has gracefully ended.
default boolean	onError(java.lang.Throwable error)	Called to notify there was an error in the commit reader.
default boolean	onException(java.lang.Exception exception)	Called to notify there was an exception in the commit reader.
default boolean	onFatalError(java.lang.Error error)	Called to notify there was an error in the commit reader.
boolean	onNext(StreamElement element, ContextT context)	Process next record in the commit log.

Method Detail

onCompleted

default void onCompleted()

Notify that the processing has gracefully ended.

onCancelled

default void onCancelled()

Notify that the processing has been canceled.

onError

default boolean onError(java.lang.Throwable error)

Called to notify there was an error in the commit reader.

Parameters:

error - error caught during processing

Returns:

true to restart processing from last committed position, false to stop processing

onException

default boolean onException(java.lang.Exception exception)

Called to notify there was an exception in the commit reader. There is no guarantee this method gets called, if onError(Throwable) is overridden.

Parameters:

exception - exception caught during processing

Returns:

true to restart processing from last committed position, false to stop processing

onFatalError

default boolean onFatalError(java.lang.Error error)

Called to notify there was an error in the commit reader. There is no guarantee this method gets called, if onError(Throwable) is overridden.

Parameters:

error - error caught during processing

Returns:

true to restart processing from last committed position, false to stop processing

onNext

boolean onNext(StreamElement element,
               ContextT context)

Process next record in the commit log.

Parameters:

element - the element written to the commit log

context - a context that the application must use to confirm processing of the element. If the application fails to do so, the result is undefined.

Returns:

true if the processing should continue, false otherwise