Class FixedWindowRollingPolicy

java.lang.Object
org.apache.log4j.rolling.RollingPolicyBase
org.apache.log4j.rolling.FixedWindowRollingPolicy
All Implemented Interfaces:
RollingPolicy, org.apache.log4j.spi.OptionHandler
public final class FixedWindowRollingPolicy extends RollingPolicyBase
When rolling over, FixedWindowRollingPolicy renames files according to a fixed window algorithm as described below.

The ActiveFileName property, which is required, represents the name of the file where current logging output will be written. The FileNamePattern option represents the file name pattern for the archived (rolled over) log files. If present, the FileNamePattern option must include an integer token, that is the string "%i" somewhere within the pattern.

Let max and min represent the values of respectively the MaxIndex and MinIndex options. Let "foo.log" be the value of the ActiveFile option and "foo.%i.log" the value of FileNamePattern. Then, when rolling over, the file foo.max.log will be deleted, the file foo.max-1.log will be renamed as foo.max.log, the file foo.max-2.log renamed as foo.max-1.log, and so on, the file foo.min+1.log renamed as foo.min+2.log. Lastly, the active file foo.log will be renamed as foo.min.log and a new active file name foo.log will be created.

Given that this rollover algorithm requires as many file renaming operations as the window size, large window sizes are discouraged. The current implementation will automatically reduce the window size to 12 when larger values are specified by the user.

Author:
Ceki Gülcü

  • Constructor Details

    • FixedWindowRollingPolicy

      public FixedWindowRollingPolicy()
      Constructs a new instance.

  • Method Details

    • activateOptions

      public void activateOptions()
      Specified by:
      activateOptions in interface org.apache.log4j.spi.OptionHandler
      Overrides:
      activateOptions in class RollingPolicyBase

    • initialize

      public RolloverDescription initialize(String file, boolean append)
      Initialize the policy and return any initial actions for rolling file appender..
      Parameters:
      file - 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

      public RolloverDescription rollover(String currentFileName)
      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.
      Parameters:
      currentFileName - file name for current active log file.
      Returns:
      Description of pending rollover, may be null to indicate no rollover at this time.

    • getMaxIndex

      public int getMaxIndex()
      Get index of oldest log file to be retained.
      Returns:
      index of oldest log file.

    • getMinIndex

      public int getMinIndex()
      Get index of most recent log file.
      Returns:
      index of oldest log file.

    • setMaxIndex

      public void setMaxIndex(int maxIndex)
      Set index of oldest log file to be retained.
      Parameters:
      maxIndex - index of oldest log file to be retained.

    • setMinIndex

      public void setMinIndex(int minIndex)
      Set index of most recent log file.
      Parameters:
      minIndex - Index of most recent log file.