Class TimeBasedRollingPolicy
- All Implemented Interfaces:
RollingPolicy
,TriggeringPolicy
,org.apache.log4j.spi.OptionHandler
TimeBasedRollingPolicy
is both easy to configure and quite
powerful.
In order to use TimeBasedRollingPolicy
, the
FileNamePattern option must be set. It basically specifies the name of the
rolled log files. The value FileNamePattern
should consist of
the name of the file, plus a suitably placed %d
conversion
specifier. The %d
conversion specifier may contain a date and
time pattern as specified by the SimpleDateFormat
class. If
the date and time pattern is ommitted, then the default pattern of
"yyyy-MM-dd" is assumed. The following examples should clarify the point.
FileNamePattern value |
Rollover schedule | Example |
---|---|---|
/wombat/folder/foo.%d |
Daily rollover (at midnight). Due to the omission of the optional time and date pattern for the %d token specifier, the default pattern of "yyyy-MM-dd" is assumed, which corresponds to daily rollover. | During November 23rd, 2004, logging output will go to
the file /wombat/foo.2004-11-23 . At midnight and for
the rest of the 24th, logging output will be directed to
/wombat/foo.2004-11-24 .
|
/wombat/foo.%d{yyyy-MM}.log |
Rollover at the beginning of each month. | During the month of October 2004, logging output will go to
/wombat/foo.2004-10.log . After midnight of October 31st
and for the rest of November, logging output will be directed to
/wombat/foo.2004-11.log .
|
Automatic file compression
TimeBasedRollingPolicy
supports automatic file compression.
This feature is enabled if the value of the FileNamePattern option
ends with .gz
or .zip
.
FileNamePattern value |
Rollover schedule | Example |
---|---|---|
/wombat/foo.%d.gz |
Daily rollover (at midnight) with automatic GZIP compression of the archived files. | During November 23rd, 2004, logging output will go to
the file /wombat/foo.2004-11-23 . However, at midnight that
file will be compressed to become /wombat/foo.2004-11-23.gz .
For the 24th of November, logging output will be directed to
/wombat/folder/foo.2004-11-24 until its rolled over at the
beginning of the next day.
|
Decoupling the location of the active log file and the archived log files
The active file is defined as the log file for the current period whereas archived files are those files which have been rolled over in previous periods.
By setting the ActiveFileName option you can decouple the location of the active log file and the location of the archived log files.
FileNamePattern value |
ActiveFileName | Rollover schedule | Example |
---|---|---|---|
/wombat/foo.log.%d |
/wombat/foo.log |
Daily rollover. | During November 23rd, 2004, logging output will go to
the file /wombat/foo.log . However, at midnight that file
will archived as /wombat/foo.log.2004-11-23 . For the 24th
of November, logging output will be directed to
/wombat/folder/foo.log until its archived as
/wombat/foo.log.2004-11-24 at the beginning of the next
day.
|
If configuring programatically, do not forget to call activateOptions()
method before using this policy. Moreover, activateOptions()
of
TimeBasedRollingPolicy
must be called before calling
the activateOptions()
method of the owning
RollingFileAppender
.
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate String
File name at last rollover.private long
Time for next determination if time for rollover.private int
Length of any file type suffix (.gz, .zip).Fields inherited from class org.apache.log4j.rolling.RollingPolicyBase
activeFileName
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
Prepares instance of use.initialize
(String currentActiveFile, boolean append) Initialize the policy and return any initial actions for rolling file appender..boolean
isTriggeringEvent
(org.apache.log4j.Appender appender, org.apache.log4j.spi.LoggingEvent event, String filename, long fileLength) Determines if a rollover may be appropriate at this time.Prepare for a rollover.Methods inherited from class org.apache.log4j.rolling.RollingPolicyBase
formatFileName, getActiveFileName, getDatePatternConverter, getFileNamePattern, getIntegerPatternConverter, parseFileNamePattern, setActiveFileName, setFileNamePattern
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Field Details
-
nextCheck
private long nextCheckTime for next determination if time for rollover. -
lastFileName
File name at last rollover. -
suffixLength
private int suffixLengthLength of any file type suffix (.gz, .zip).
-
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Constructor Details
-
TimeBasedRollingPolicy
public TimeBasedRollingPolicy()Constructs a new instance.
-
-
Method Details
-
activateOptions
public void activateOptions()Prepares instance of use.- Specified by:
activateOptions
in interfaceorg.apache.log4j.spi.OptionHandler
- Overrides:
activateOptions
in classRollingPolicyBase
-
initialize
Initialize the policy and return any initial actions for rolling file appender..- Specified by:
initialize
in interfaceRollingPolicy
- Parameters:
currentActiveFile
- current value of RollingFileAppender.getFile().append
- current value of RollingFileAppender.getAppend().- Returns:
- Description of the initialization, may be null to indicate no initialization needed.
-
rollover
Prepare for a rollover. This method is called prior to closing the active log file, performs any necessary preliminary actions and describes actions needed after close of current log file.- Specified by:
rollover
in interfaceRollingPolicy
- Parameters:
currentActiveFile
- file name for current active log file.- Returns:
- Description of pending rollover, may be null to indicate no rollover at this time.
-
isTriggeringEvent
public boolean isTriggeringEvent(org.apache.log4j.Appender appender, org.apache.log4j.spi.LoggingEvent event, String filename, long fileLength) Determines if a rollover may be appropriate at this time. If true is returned, RolloverPolicy.rollover will be called but it can determine that a rollover is not warranted.- Specified by:
isTriggeringEvent
in interfaceTriggeringPolicy
- Parameters:
appender
- A reference to the appender.event
- A reference to the currently event.filename
- The filename for the currently active log file.fileLength
- Length of the file in bytes.- Returns:
- true if a rollover should occur.
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