org.tools4j.elara.log

Class DefaultIndexTrackingPoller

java.lang.Object

org.tools4j.elara.log.DefaultIndexTrackingPoller

All Implemented Interfaces:

IndexTrackingPoller, MessageLog.Poller

public class DefaultIndexTrackingPoller
extends Object
implements IndexTrackingPoller

Constructor Summary

Constructors

Constructor and Description
DefaultIndexTrackingPoller(MessageLog messageLog)

Method Summary

Modifier and Type	Method and Description
long	entryId() Returns the current entry ID of this poller.
long	index() Returns the current index of this poller.
boolean	moveTo(long entryId)
MessageLog.Poller	moveToEnd() NOTE: this method is possibly slow if it has to move a lot of positions! Moves to the end of the message log.
boolean	moveToIndex(long index) NOTE: this method is possibly slow if it has to move a lot of positions! Moves to the specified index
boolean	moveToNext()
boolean	moveToPrevious()
DefaultIndexTrackingPoller	moveToStart()
int	poll(MessageLog.Handler handler)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.tools4j.elara.log.IndexTrackingPoller

create

Constructor Detail

DefaultIndexTrackingPoller

public DefaultIndexTrackingPoller(MessageLog messageLog)

Method Detail

index

public long index()

Description copied from interface: IndexTrackingPoller

Returns the current index of this poller.

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

The index monotonically increasing and gap free.

Specified by:

index in interface IndexTrackingPoller

Returns:

the current index of this poller.

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.

moveTo

public boolean moveTo(long entryId)

Specified by:

moveTo in interface MessageLog.Poller

moveToIndex

public boolean moveToIndex(long index)

Description copied from interface: IndexTrackingPoller

NOTE: this method is possibly slow if it has to move a lot of positions! Moves to the specified index

Specified by:

moveToIndex in interface IndexTrackingPoller

Parameters:

index - the index to move to, valid from zero to (#entries - 1)

Returns:

true if such an index is found

moveToNext

public boolean moveToNext()

Specified by:

moveToNext in interface MessageLog.Poller

moveToPrevious

public boolean moveToPrevious()

Specified by:

moveToPrevious in interface MessageLog.Poller

moveToStart

public DefaultIndexTrackingPoller moveToStart()

Specified by:

moveToStart in interface MessageLog.Poller

moveToEnd

public MessageLog.Poller moveToEnd()

Description copied from interface: IndexTrackingPoller

NOTE: this method is possibly slow if it has to move a lot of positions! Moves to the end of the message log.

Specified by:

moveToEnd in interface IndexTrackingPoller

Specified by:

moveToEnd in interface MessageLog.Poller

Returns:

this poller

poll

public int poll(MessageLog.Handler handler)

Specified by:

poll in interface MessageLog.Poller