org.tools4j.elara.log

Class CommittedEventPoller

java.lang.Object

org.tools4j.elara.log.CommittedEventPoller

All Implemented Interfaces:

MessageLog.Poller

public class CommittedEventPoller
extends Object
implements MessageLog.Poller

An event poller that works with two underlying pollers to ensure only committed events are passed to the event handler. The lookahead poller reads ahead until either a commit or abort event is found; the event poller then invokes the handler for the corresponding events or skips them if they were aborted.

Constructor Summary

Constructors

Constructor and Description
CommittedEventPoller(MessageLog eventLog)
CommittedEventPoller(MessageLog eventLog, String id)

Method Summary

Modifier and Type	Method and Description
long	entryId() Returns the current entry ID of this poller.
boolean	moveTo(long entryId)
MessageLog.Poller	moveToEnd()
boolean	moveToNext()
boolean	moveToPrevious()
MessageLog.Poller	moveToStart()
int	poll(MessageLog.Handler handler)

Methods inherited from class java.lang.Object

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

Constructor Detail

CommittedEventPoller

public CommittedEventPoller(MessageLog eventLog)

CommittedEventPoller

public CommittedEventPoller(MessageLog eventLog,
                            String id)

Method Detail

entryId

public long entryId()

Description copied from interface: MessageLog.Poller

Returns the current entry ID of this poller.

It returns the entry ID of the message currently polled if invoked while polling a message. Otherwise it returns the entry ID of the next message to be polled.

The index is monotonically increasing but not necessarily gap free; for instance for a chronicle message log the entry ID consists of cycle and the sequence number within that cycle.

Specified by:

entryId in interface MessageLog.Poller

Returns:

the current entry ID of this poller.

moveToStart

public MessageLog.Poller moveToStart()

Specified by:

moveToStart in interface MessageLog.Poller

moveToEnd

public MessageLog.Poller moveToEnd()

Specified by:

moveToEnd in interface MessageLog.Poller

moveToNext

public boolean moveToNext()

Specified by:

moveToNext in interface MessageLog.Poller

moveToPrevious

public boolean moveToPrevious()

Specified by:

moveToPrevious in interface MessageLog.Poller

moveTo

public boolean moveTo(long entryId)

Specified by:

moveTo in interface MessageLog.Poller

poll

public int poll(MessageLog.Handler handler)

Specified by:

poll in interface MessageLog.Poller