Class AppenderSkeleton

java.lang.Object
org.apache.log4j.AppenderSkeleton
All Implemented Interfaces:
Appender, OptionHandler
Direct Known Subclasses:
AsyncAppender, JDBCAppender, JMSAppender, NullAppender, RewriteAppender, SMTPAppender, SocketAppender, SocketHubAppender, SyslogAppender, TelnetAppender, WriterAppender

public abstract class AppenderSkeleton extends Object implements Appender, OptionHandler
Abstract superclass of the other appenders in the package. This class provides the code for common functionality, such as support for threshold filtering and support for general filters.
Since:
0.8.1
Author:
Ceki Gülcü
  • Field Details

    • layout

      protected Layout layout
      The layout variable does not need to be set if the appender implementation has its own layout.
    • name

      protected String name
      Appenders are named.
    • threshold

      protected Priority threshold
      There is no level threshold filtering by default.
    • errorHandler

      protected ErrorHandler errorHandler
      It is assumed and enforced that errorHandler is never null.
    • headFilter

      protected Filter headFilter
      The first filter in the filter chain. Set to null initially.
    • tailFilter

      protected Filter tailFilter
      The last filter in the filter chain.
    • closed

      protected boolean closed
      Is this appender closed?
  • Constructor Details

    • AppenderSkeleton

      public AppenderSkeleton()
      Create new instance.
    • AppenderSkeleton

      protected AppenderSkeleton(boolean isActive)
      Create new instance. Provided for compatibility with log4j 1.3.
      Parameters:
      isActive - true if appender is ready for use upon construction. Not used in log4j 1.2.x.
      Since:
      1.2.15
  • Method Details

    • activateOptions

      public void activateOptions()
      Derived appenders should override this method if option structure requires it.
      Specified by:
      activateOptions in interface OptionHandler
    • addFilter

      public void addFilter(Filter newFilter)
      Add a filter to end of the filter list.
      Specified by:
      addFilter in interface Appender
      Since:
      0.9.0
    • append

      protected abstract void append(LoggingEvent event)
      Subclasses of AppenderSkeleton should implement this method to perform actual logging. See also AppenderSkeleton.doAppend method.
      Since:
      0.9.0
    • clearFilters

      public void clearFilters()
      Clear the filters chain.
      Specified by:
      clearFilters in interface Appender
      Since:
      0.9.0
    • finalize

      public void finalize()
      Finalize this appender by calling the derived class' close method.
      Overrides:
      finalize in class Object
      Since:
      0.8.4
    • getErrorHandler

      public ErrorHandler getErrorHandler()
      Return the currently set ErrorHandler for this Appender.
      Specified by:
      getErrorHandler in interface Appender
      Since:
      0.9.0
    • getFilter

      public Filter getFilter()
      Returns the head Filter.
      Specified by:
      getFilter in interface Appender
      Returns:
      the head Filter or null, if no Filters are present
      Since:
      1.1
    • getFirstFilter

      public final Filter getFirstFilter()
      Return the first filter in the filter chain for this Appender. The return value may be null if no is filter is set.
    • getLayout

      public Layout getLayout()
      Returns the layout of this appender. The value may be null.
      Specified by:
      getLayout in interface Appender
    • getName

      public final String getName()
      Returns the name of this appender.
      Specified by:
      getName in interface Appender
      Returns:
      name, may be null.
    • getThreshold

      public Priority getThreshold()
      Returns this appenders threshold level. See the setThreshold(org.apache.log4j.Priority) method for the meaning of this option.
      Since:
      1.1
    • isAsSevereAsThreshold

      public boolean isAsSevereAsThreshold(Priority priority)
      Check whether the message level is below the appender's threshold. If there is no threshold set, then the return value is always true.
    • doAppend

      public void doAppend(LoggingEvent event)
      This method performs threshold checks and invokes filters before delegating actual logging to the subclasses specific append(org.apache.log4j.spi.LoggingEvent) method.
      Specified by:
      doAppend in interface Appender
    • setErrorHandler

      public void setErrorHandler(ErrorHandler eh)
      Set the ErrorHandler for this Appender.
      Specified by:
      setErrorHandler in interface Appender
      Since:
      0.9.0
    • setLayout

      public void setLayout(Layout layout)
      Set the layout for this appender. Note that some appenders have their own (fixed) layouts or do not use one. For example, the SocketAppender ignores the layout set here.
      Specified by:
      setLayout in interface Appender
    • setName

      public void setName(String name)
      Set the name of this Appender.
      Specified by:
      setName in interface Appender
    • setThreshold

      public void setThreshold(Priority threshold)
      Set the threshold level. All log events with lower level than the threshold level are ignored by the appender.

      In configuration files this option is specified by setting the value of the Threshold option to a level string, such as "DEBUG", "INFO" and so on.

      Since:
      0.8.3