Interface LogEventListener
- All Known Implementing Classes:
XALogger
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.
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
used to log low level events.static final int
used to log non-fatal error messages.static final int
used to log fatal error messages that should cause shutdown of the application using HOWL.static final int
used to log information messages such as file open/close.static final int
used to trace method entry/exit and other low level events.static final int
used to log warnings. -
Method Summary
Modifier and TypeMethodDescriptionboolean
isLoggable
(int level) determine if log messages for requested level will be written to the log.void
write a log message to the event log.void
write a log message to the event log with exception information.void
logOverflowNotification
(long logkey) Called by Logger to notify the LogEventListener that a log file overflow is approaching.
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Field Details
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TRACE
static final int TRACEused to trace method entry/exit and other low level events.- See Also:
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DEBUG
static final int DEBUGused to log low level events.- See Also:
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INFO
static final int INFOused to log information messages such as file open/close.- See Also:
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WARN
static final int WARNused to log warnings.- See Also:
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ERROR
static final int ERRORused to log non-fatal error messages.- See Also:
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FATAL
static final int FATALused to log fatal error messages that should cause shutdown of the application using HOWL.- See Also:
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Method Details
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logOverflowNotification
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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isLoggable
boolean isLoggable(int level) determine if log messages for requested level will be written to the log.- Returns:
- true if the log level is being logged
- See Also:
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log
write a log message to the event log.- Parameters:
level
- log levelmessage
- text to be logged
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log
write a log message to the event log with exception information.- Parameters:
level
- log levelmessage
- text to be loggedthrown
- Throwable related to the event being logged.
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