public class TrackingEventProcessor extends AbstractEventProcessor
StreamableMessageSource
.
A supplied TokenStore
allows the EventProcessor to keep track of its position in the event log. After
processing an event batch the EventProcessor updates its tracking token in the TokenStore.
A TrackingEventProcessor is able to continue processing from the last stored token when it is restarted. It is also capable of replaying events from any starting token. To replay the entire event log simply remove the tracking token of this processor from the TokenStore. To replay from a given point first update the entry for this processor in the TokenStore before starting this processor.
Note, the name
of the EventProcessor is used to obtain the tracking token from the TokenStore, so
take care when renaming a TrackingEventProcessor.
Modifier and Type | Class and Description |
---|---|
protected static class |
TrackingEventProcessor.State |
Constructor and Description |
---|
TrackingEventProcessor(String name,
EventHandlerInvoker eventHandlerInvoker,
StreamableMessageSource<TrackedEventMessage<?>> messageSource,
TokenStore tokenStore,
TransactionManager transactionManager)
Initializes an EventProcessor with given
name that subscribes to the given messageSource for
events. |
TrackingEventProcessor(String name,
EventHandlerInvoker eventHandlerInvoker,
StreamableMessageSource<TrackedEventMessage<?>> messageSource,
TokenStore tokenStore,
TransactionManager transactionManager,
MessageMonitor<? super EventMessage<?>> messageMonitor)
Initializes an EventProcessor with given
name that subscribes to the given messageSource for
events. |
TrackingEventProcessor(String name,
EventHandlerInvoker eventHandlerInvoker,
StreamableMessageSource<TrackedEventMessage<?>> messageSource,
TokenStore tokenStore,
TransactionManager transactionManager,
MessageMonitor<? super EventMessage<?>> messageMonitor,
RollbackConfiguration rollbackConfiguration,
ErrorHandler errorHandler,
TrackingEventProcessorConfiguration config)
Initializes an EventProcessor with given
name that subscribes to the given messageSource for
events. |
Modifier and Type | Method and Description |
---|---|
int |
activeProcessorThreads()
Returns an approximation of the number of threads currently processing events.
|
protected TrackingEventProcessor.State |
getState()
Get the state of the event processor.
|
boolean |
isError()
Indicates whether the processor has been paused due to an error.
|
boolean |
isRunning()
Indicates whether this processor is currently running (i.e.
|
void |
pause()
Stops processing if it currently running, but doesn't stop free up the processing thread.
|
protected void |
processingLoop(Segment segment)
Fetch and process event batches continuously for as long as the processor is not shutting down.
|
void |
shutDown()
Shut down the processor.
|
void |
start()
Start this processor.
|
protected void |
startSegmentWorkers()
Starts the
workers for a number of segments. |
canHandle, getName, processInUnitOfWork, registerInterceptor, reportIgnored, toString
public TrackingEventProcessor(String name, EventHandlerInvoker eventHandlerInvoker, StreamableMessageSource<TrackedEventMessage<?>> messageSource, TokenStore tokenStore, TransactionManager transactionManager)
name
that subscribes to the given messageSource
for
events. Actual handling of event messages is deferred to the given eventHandlerInvoker
.
The EventProcessor is initialized with a batch size of 1, a PropagatingErrorHandler
, a RollbackConfigurationType.ANY_THROWABLE
and a NoOpMessageMonitor
.
name
- The name of the event processoreventHandlerInvoker
- The component that handles the individual eventsmessageSource
- The message source (e.g. Event Bus) which this event processor will tracktokenStore
- Used to store and fetch event tokens that enable the processor to track its progresstransactionManager
- The transaction manager used when processing messagespublic TrackingEventProcessor(String name, EventHandlerInvoker eventHandlerInvoker, StreamableMessageSource<TrackedEventMessage<?>> messageSource, TokenStore tokenStore, TransactionManager transactionManager, MessageMonitor<? super EventMessage<?>> messageMonitor)
name
that subscribes to the given messageSource
for
events. Actual handling of event messages is deferred to the given eventHandlerInvoker
.
The EventProcessor is initialized with a batch size of 1, a PropagatingErrorHandler
and a RollbackConfigurationType.ANY_THROWABLE
.
name
- The name of the event processoreventHandlerInvoker
- The component that handles the individual eventsmessageSource
- The message source (e.g. Event Bus) which this event processor will tracktokenStore
- Used to store and fetch event tokens that enable the processor to track its progresstransactionManager
- The transaction manager used when processing messagesmessageMonitor
- Monitor to be invoked before and after event processingpublic TrackingEventProcessor(String name, EventHandlerInvoker eventHandlerInvoker, StreamableMessageSource<TrackedEventMessage<?>> messageSource, TokenStore tokenStore, TransactionManager transactionManager, MessageMonitor<? super EventMessage<?>> messageMonitor, RollbackConfiguration rollbackConfiguration, ErrorHandler errorHandler, TrackingEventProcessorConfiguration config)
name
that subscribes to the given messageSource
for
events. Actual handling of event messages is deferred to the given eventHandlerInvoker
.name
- The name of the event processoreventHandlerInvoker
- The component that handles the individual eventsmessageSource
- The message source (e.g. Event Bus) which this event processor will tracktokenStore
- Used to store and fetch event tokens that enable the processor to track its
progresstransactionManager
- The transaction manager used when processing messagesmessageMonitor
- Monitor to be invoked before and after event processingrollbackConfiguration
- Determines rollback behavior of the UnitOfWork while processing a batch of eventserrorHandler
- Invoked when a UnitOfWork is rolled back during processingconfig
- The configuration for the event processor.public void start()
StreamableMessageSource.openStream(TrackingToken)
. The TrackingToken
used to open the stream will be
fetched from the TokenStore
.protected void processingLoop(Segment segment)
Events with the same tracking token (which is possible as result of upcasting) should always be processed in the same batch. In those cases the batch size may be larger than the one configured.
segment
- The Segment
of the Stream that should be processed.public void pause()
public boolean isRunning()
true
when running, otherwise false
public boolean isError()
Note that this method also returns false
when the processor was paused using pause()
.
true
when paused due to an error, otherwise false
public void shutDown()
public int activeProcessorThreads()
protected TrackingEventProcessor.State getState()
protected void startSegmentWorkers()
workers
for a number of segments. When only the
root
segment exists
in the TokenStore,
it will be split in multiple segments as configured by the
TrackingEventProcessorConfiguration.andInitialSegmentsCount(int)
, otherwise the existing segments in
the TokenStore will be used.
An attempt will be made to instantiate a TrackingSegmentWorker
for each segment. This will succeed when
the number of threads matches the requested segments. The number of active threads can be configured with
TrackingEventProcessorConfiguration.forParallelProcessing(int)
. When insufficient threads are available
to serve the number of segments, it will result in some segments not being processed.Copyright © 2010–2017. All rights reserved.