Package org.apache.log4j.rolling

Class 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

    • 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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void activateOptions()
      Prepare instance of use.
      void close()
      Close appender.
      private java.io.FileOutputStream createFileOutputStream​(java.lang.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​(java.io.Writer writer)  
      protected java.io.OutputStreamWriter createWriter​(java.io.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​(org.w3c.dom.Element element, java.util.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 java.lang.Object

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

    • Field Detail

      • 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 Detail

      • RollingFileAppender

        public RollingFileAppender()
        Construct a new instance.

    • Method Detail

      • 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​(java.io.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 java.io.FileOutputStream createFileOutputStream​(java.lang.String newFileName,
                                                        boolean append)
                                                 throws java.io.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:
        java.io.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 java.io.OutputStreamWriter createWriter​(java.io.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​(org.w3c.dom.Element element,
                                        java.util.Properties props)
                                 throws java.lang.Exception
        Specified by:
        parseUnrecognizedElement in interface org.apache.log4j.xml.UnrecognizedElementHandler
        Throws:
        java.lang.Exception