Class RollingFileAppender

java.lang.Object
org.apache.log4j.AppenderSkeleton
org.apache.log4j.WriterAppender
org.apache.log4j.FileAppender
org.apache.log4j.rolling.RollingFileAppender
All Implemented Interfaces:
org.apache.log4j.Appender, org.apache.log4j.spi.OptionHandler, org.apache.log4j.xml.UnrecognizedElementHandler
public final class RollingFileAppender extends org.apache.log4j.FileAppender implements org.apache.log4j.xml.UnrecognizedElementHandler
RollingFileAppender extends FileAppender to backup the log files depending on RollingPolicy and TriggeringPolicy.

To be of any use, a RollingFileAppender instance must have both a RollingPolicy and a TriggeringPolicy set up. However, if its RollingPolicy also implements the TriggeringPolicy interface, then only the former needs to be set up. For example, TimeBasedRollingPolicy acts both as a RollingPolicy and a TriggeringPolicy.

RollingFileAppender can be configured programattically or using DOMConfigurator or DOMConfigurator in log4j 1.2.15 or later. Here is a sample configration file: 

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration>

<log4j:configuration debug="true">

  <appender name="ROLL" class="org.apache.log4j.rolling.RollingFileAppender">
    <rollingPolicy class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
      <param name="FileNamePattern" value="/wombat/foo.%d{yyyy-MM}.gz"/>
    </rollingPolicy>

    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%c{1} - %m%n"/>
    </layout>
  </appender>

  <root">
    <appender-ref ref="ROLL"/>
  </root>

</log4j:configuration>

This configuration file specifies a monthly rollover schedule including automatic compression of the archived files. See TimeBasedRollingPolicy for more details.

Since:
1.3

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    private static class 
    RollingFileAppender.CountingOutputStream
    Wrapper for OutputStream that will report all write operations back to this class for file length calculations.
    private static final class 
    RollingFileAppender.DefaultErrorHandler
     

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private long
    fileLength
    Length of current active log file.
    private Action
    lastRolloverAsyncAction
    Asynchronous action (like compression) from previous rollover.
    private RollingPolicy
    rollingPolicy
    Rolling policy.
    private TriggeringPolicy
    triggeringPolicy
    Triggering policy.

    Fields inherited from class org.apache.log4j.FileAppender

    bufferedIO, bufferSize, fileAppend, fileName

    Fields inherited from class org.apache.log4j.WriterAppender

    encoding, immediateFlush, qw

    Fields inherited from class org.apache.log4j.AppenderSkeleton

    closed, errorHandler, headFilter, layout, name, tailFilter, threshold

  • Constructor Summary

    Constructors
    Constructor
    Description
    RollingFileAppender()
    Construct a new instance.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    activateOptions()
    Prepare instance of use.
    void
    close()
    Close appender.
    private FileOutputStream
    createFileOutputStream(String newFileName, boolean append)
    Creates a new FileOutputStream of a new log file, possibly creating first all the needed parent directories
    private org.apache.log4j.helpers.QuietWriter
    createQuietWriter(Writer writer)
     
    protected OutputStreamWriter
    createWriter(OutputStream os)
    Returns an OutputStreamWriter when passed an OutputStream.
    long
    getFileLength()
    Get byte length of current active log file.
    RollingPolicy
    getRollingPolicy()
    Get rolling policy.
    TriggeringPolicy
    getTriggeringPolicy()
    Get triggering policy.
    void
    incrementFileLength(int increment)
    Increments estimated byte length of current active log file.
    boolean
    parseUnrecognizedElement(Element element, Properties props)
    boolean
    rollover()
    Implements the usual roll over behaviour.
    void
    setRollingPolicy(RollingPolicy policy)
    Sets the rolling policy.
    void
    setTriggeringPolicy(TriggeringPolicy policy)
    Set triggering policy.
    protected void
    subAppend(org.apache.log4j.spi.LoggingEvent event)

    Methods inherited from class org.apache.log4j.FileAppender

    closeFile, getAppend, getBufferedIO, getBufferSize, getFile, reset, setAppend, setBufferedIO, setBufferSize, setFile, setFile, setQWForFiles

    Methods inherited from class org.apache.log4j.WriterAppender

    append, checkEntryConditions, closeWriter, getEncoding, getImmediateFlush, requiresLayout, setEncoding, setErrorHandler, setImmediateFlush, setWriter, shouldFlush, writeFooter, writeHeader

    Methods inherited from class org.apache.log4j.AppenderSkeleton

    addFilter, clearFilters, doAppend, finalize, getErrorHandler, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setLayout, setName, setThreshold

    Methods inherited from class Object

    clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • triggeringPolicy

      private TriggeringPolicy triggeringPolicy
      Triggering policy.

    • rollingPolicy

      private RollingPolicy rollingPolicy
      Rolling policy.

    • fileLength

      private long fileLength
      Length of current active log file.

    • lastRolloverAsyncAction

      private Action lastRolloverAsyncAction
      Asynchronous action (like compression) from previous rollover.

  • Constructor Details

    • RollingFileAppender

      public RollingFileAppender()
      Construct a new instance.

  • Method Details

    • activateOptions

      public void activateOptions()
      Prepare instance of use.
      Specified by:
      activateOptions in interface org.apache.log4j.spi.OptionHandler
      Overrides:
      activateOptions in class org.apache.log4j.FileAppender

    • createQuietWriter

      private org.apache.log4j.helpers.QuietWriter createQuietWriter(Writer writer)

    • rollover

      public boolean rollover()
      Implements the usual roll over behaviour.

      If MaxBackupIndex is positive, then files {File.1, ..., File.MaxBackupIndex -1} are renamed to {File.2, ..., File.MaxBackupIndex}. Moreover, File is renamed File.1 and closed. A new File is created to receive further log output.

      If MaxBackupIndex is equal to zero, then the File is truncated with no backup files created.

      Returns:
      true if rollover performed.

    • createFileOutputStream

      private FileOutputStream createFileOutputStream(String newFileName, boolean append) throws FileNotFoundException
      Creates a new FileOutputStream of a new log file, possibly creating first all the needed parent directories
      Parameters:
      newFileName - Filename of new log file to be created
      append - If file should be appended
      Returns:
      newly created FileOutputStream
      Throws:
      FileNotFoundException - if creating log file or parent directories was unsuccessful

    • subAppend

      protected void subAppend(org.apache.log4j.spi.LoggingEvent event)
      Overrides:
      subAppend in class org.apache.log4j.WriterAppender

    • getRollingPolicy

      public RollingPolicy getRollingPolicy()
      Get rolling policy.
      Returns:
      rolling policy.

    • getTriggeringPolicy

      public TriggeringPolicy getTriggeringPolicy()
      Get triggering policy.
      Returns:
      triggering policy.

    • setRollingPolicy

      public void setRollingPolicy(RollingPolicy policy)
      Sets the rolling policy.
      Parameters:
      policy - rolling policy.

    • setTriggeringPolicy

      public void setTriggeringPolicy(TriggeringPolicy policy)
      Set triggering policy.
      Parameters:
      policy - triggering policy.

    • close

      public void close()
      Close appender. Waits for any asynchronous file compression actions to be completed.
      Specified by:
      close in interface org.apache.log4j.Appender
      Overrides:
      close in class org.apache.log4j.WriterAppender

    • createWriter

      protected OutputStreamWriter createWriter(OutputStream os)
      Returns an OutputStreamWriter when passed an OutputStream. The encoding used will depend on the value of the encoding property. If the encoding value is specified incorrectly the writer will be opened using the default system encoding (an error message will be printed to the loglog.
      Overrides:
      createWriter in class org.apache.log4j.WriterAppender
      Parameters:
      os - output stream, may not be null.
      Returns:
      new writer.

    • getFileLength

      public long getFileLength()
      Get byte length of current active log file.
      Returns:
      byte length of current active log file.

    • incrementFileLength

      public void incrementFileLength(int increment)
      Increments estimated byte length of current active log file.
      Parameters:
      increment - additional bytes written to log file.

    • parseUnrecognizedElement

      public boolean parseUnrecognizedElement(Element element, Properties props) throws Exception
      Specified by:
      parseUnrecognizedElement in interface org.apache.log4j.xml.UnrecognizedElementHandler
      Throws:
      Exception