org.objectweb.howl.log
Interface LogEventListener

All Known Implementing Classes:
XALogger

public interface LogEventListener

This interface is implemented by users of the Logger.

If a LogEventListener is registered, the logger will call the LogEventListener when interesting Log Events occur. For example, the Logger will notify the LogEventListener when the current log file is 50% full to allow the application to copy old log entries forward.

If the application does not register a LogEventListener it will not have visibility to Log events.

Author:
Michael Giroux

Method Summary
 void logOverflowNotification(long logkey)
          Called by Logger to notify the LogEventListener that a log file overflow is approaching.
 

Method Detail

logOverflowNotification

public void logOverflowNotification(long logkey)
Called by Logger to notify the LogEventListener that a log file overflow is approaching.

Parameters:
logkey - lowest safe log key.

LogEventListener should cause log records with keys less than logkey to be copied forward to prevent a LogOverflowException.

Hopefully, the LogEventListener will be able to regenerate the records from memory without having to read the physical log file. For example, a Transaction Manager should maintain a table of transactions that are in the COMMITTING mode, with associated log key for each transaction. The logOverflowNotification method would call Logger.put() for each transaction that has a log key less than logKey .

Before returning from logOverflowNotification the LogEventListener should call Logger.mark(newMark, force) with force set to true to assure that the new records have been committed to physical disk.



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