com.continuent.tungsten.replicator.thl.log
Class LogCursorManager

java.lang.Object
  com.continuent.tungsten.replicator.thl.log.LogCursorManager

public class LogCursorManager
extends java.lang.Object

Encapsulates management of connections and their log cursors. Log cursors are a position in a particular log file and can only move in a forward direction. If clients move backward in the log we need to allocated a new cursor.

Author:

Robert Hodges

Constructor Summary

LogCursorManager()
Create a new log cursor manager.

Method Summary

LogCursor	createAndGetLogCursor(LogConnection client, LogFile logFile, long lastSeqno) Sets the log file and last accessed sequence number for this thread.
LogCursor	getLogCursor(LogConnection client, long nextSeqno) Return a cursor to the log file belonging to this client.
int	getSize() Returns the number of cursors currently managed.
int	getTimeoutMillis() Returns the timeout for idle cursors.
void	release() Releases all cursors.
void	releaseConnection(LogConnection client) Releases log cursor for specific thread ID.
void	returnLogCursor(LogCursor logCursor) Returns a loaned log cursor.
void	setTimeoutMillis(int timeoutMillis) Sets the timeout for idle cursors.

Methods inherited from class java.lang.Object

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

Constructor Detail

LogCursorManager

public LogCursorManager()
                 throws ReplicatorException

Create a new log cursor manager.

Throws:

ReplicatorException

Method Detail

getSize

public int getSize()

Returns the number of cursors currently managed.

getTimeoutMillis

public int getTimeoutMillis()

Returns the timeout for idle cursors.

setTimeoutMillis

public void setTimeoutMillis(int timeoutMillis)

Sets the timeout for idle cursors. This recomputes the timeout.

getLogCursor

public LogCursor getLogCursor(LogConnection client,
                              long nextSeqno)
                       throws ReplicatorException

Return a cursor to the log file belonging to this client. If the next seqno is before the current position, we release the existing file and return null.

Returns:

A cursor. This must be returned using returnLogConnection().

Throws:

ReplicatorException

createAndGetLogCursor

public LogCursor createAndGetLogCursor(LogConnection client,
                                       LogFile logFile,
                                       long lastSeqno)
                                throws ReplicatorException

Sets the log file and last accessed sequence number for this thread. This allows clients to roll over the log cursor and receive it back as a new loaned cursor.

Returns:

A cursor. This must be returned using returnLogConnection().

Throws:

ReplicatorException

returnLogCursor

public void returnLogCursor(LogCursor logCursor)

Returns a loaned log cursor. This must be called on any cursor before asking for it again.

Parameters:

logCursor -

release

public void release()

Releases all cursors. This must be called when terminating to ensure file descriptors are released.

releaseConnection

public void releaseConnection(LogConnection client)

Releases log cursor for specific thread ID.