Class DailyRollingFileAppender

All Implemented Interfaces:
Appender, OptionHandler

public class DailyRollingFileAppender extends FileAppender
DailyRollingFileAppender extends FileAppender so that the underlying file is rolled over at a user chosen frequency. DailyRollingFileAppender has been observed to exhibit synchronization issues and data loss. The log4j extras companion includes alternatives which should be considered for new deployments and which are discussed in the documentation for org.apache.log4j.rolling.RollingFileAppender.

The rolling schedule is specified by the DatePattern option. This pattern should follow the SimpleDateFormat conventions. In particular, you must escape literal text within a pair of single quotes. A formatted version of the date pattern is used as the suffix for the rolled file name.

For example, if the File option is set to /foo/bar.log and the DatePattern set to '.'yyyy-MM-dd, on 2001-02-16 at midnight, the logging file /foo/bar.log will be copied to /foo/bar.log.2001-02-16 and logging for 2001-02-17 will continue in /foo/bar.log until it rolls over the next day.

Is is possible to specify monthly, weekly, half-daily, daily, hourly, or minutely rollover schedules.

DatePattern Rollover schedule Example
'.'yyyy-MM Rollover at the beginning of each month At midnight of May 31st, 2002 /foo/bar.log will be copied to /foo/bar.log.2002-05. Logging for the month of June will be output to /foo/bar.log until it is also rolled over the next month.
'.'yyyy-ww Rollover at the first day of each week. The first day of the week depends on the locale. Assuming the first day of the week is Sunday, on Saturday midnight, June 9th 2002, the file /foo/bar.log will be copied to /foo/bar.log.2002-23. Logging for the 24th week of 2002 will be output to /foo/bar.log until it is rolled over the next week.
'.'yyyy-MM-dd Rollover at midnight each day. At midnight, on March 8th, 2002, /foo/bar.log will be copied to /foo/bar.log.2002-03-08. Logging for the 9th day of March will be output to /foo/bar.log until it is rolled over the next day.
'.'yyyy-MM-dd-a Rollover at midnight and midday of each day. At noon, on March 9th, 2002, /foo/bar.log will be copied to /foo/bar.log.2002-03-09-AM. Logging for the afternoon of the 9th will be output to /foo/bar.log until it is rolled over at midnight.
'.'yyyy-MM-dd-HH Rollover at the top of every hour. At approximately 11:00.000 o'clock on March 9th, 2002, /foo/bar.log will be copied to /foo/bar.log.2002-03-09-10. Logging for the 11th hour of the 9th of March will be output to /foo/bar.log until it is rolled over at the beginning of the next hour.
'.'yyyy-MM-dd-HH-mm Rollover at the beginning of every minute. At approximately 11:23,000, on March 9th, 2001, /foo/bar.log will be copied to /foo/bar.log.2001-03-09-10-22. Logging for the minute of 11:23 (9th of March) will be output to /foo/bar.log until it is rolled over the next minute.

Do not use the colon ":" character in anywhere in the DatePattern option. The text before the colon is interpeted as the protocol specificaion of a URL which is probably not what you want.

Author:
Eirik Lygre, Ceki Gülcü
  • Constructor Details

    • DailyRollingFileAppender

      public DailyRollingFileAppender()
      The default constructor does nothing.
    • DailyRollingFileAppender

      public DailyRollingFileAppender(Layout layout, String filename, String datePattern) throws IOException
      Instantiate a DailyRollingFileAppender and open the file designated by filename. The opened filename will become the ouput destination for this appender.
      Throws:
      IOException
  • Method Details

    • setDatePattern

      public void setDatePattern(String pattern)
      The DatePattern takes a string in the same format as expected by SimpleDateFormat. This options determines the rollover schedule.
    • getDatePattern

      public String getDatePattern()
      Returns the value of the DatePattern option.
    • activateOptions

      public void activateOptions()
      Description copied from class: FileAppender
      If the value of File is not null, then FileAppender.setFile(java.lang.String) is called with the values of File and Append properties.
      Specified by:
      activateOptions in interface OptionHandler
      Overrides:
      activateOptions in class FileAppender
    • subAppend

      protected void subAppend(LoggingEvent event)
      This method differentiates DailyRollingFileAppender from its super class.

      Before actually logging, this method will check whether it is time to do a rollover. If it is, it will schedule the next rollover time and then rollover.

      Overrides:
      subAppend in class WriterAppender