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 java.lang.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 Summary

Fields
Modifier and Type	Field	Description
`protected boolean`	`closed`	Is this appender closed?
`protected ErrorHandler`	`errorHandler`	It is assumed and enforced that errorHandler is never null.
`protected Filter`	`headFilter`	The first filter in the filter chain.
`protected Layout`	`layout`	The layout variable does not need to be set if the appender implementation has its own layout.
`protected java.lang.String`	`name`	Appenders are named.
`protected Filter`	`tailFilter`	The last filter in the filter chain.
`protected Priority`	`threshold`	There is no level threshold filtering by default.

Constructor Summary

Constructors
Modifier Constructor Description

AppenderSkeleton()
Create new instance.

protected AppenderSkeleton(boolean isActive)
Create new instance.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`activateOptions()`	Derived appenders should override this method if option structure requires it.
`void`	`addFilter(Filter newFilter)`	Add a filter to end of the filter list.
`protected abstract void`	`append(LoggingEvent event)`	Subclasses of `AppenderSkeleton` should implement this method to perform actual logging.
`void`	`clearFilters()`	Clear the filters chain.
`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.
`void`	`finalize()`	Finalize this appender by calling the derived class' `close` method.
`ErrorHandler`	`getErrorHandler()`	Return the currently set `ErrorHandler` for this Appender.
`Filter`	`getFilter()`	Returns the head Filter.
`Filter`	`getFirstFilter()`	Return the first filter in the filter chain for this Appender.
`Layout`	`getLayout()`	Returns the layout of this appender.
`java.lang.String`	`getName()`	Returns the name of this appender.
`Priority`	`getThreshold()`	Returns this appenders threshold level.
`boolean`	`isAsSevereAsThreshold(Priority priority)`	Check whether the message level is below the appender's threshold.
`void`	`setErrorHandler(ErrorHandler eh)`	Set the `ErrorHandler` for this Appender.
`void`	`setLayout(Layout layout)`	Set the layout for this appender.
`void`	`setName(java.lang.String name)`	Set the name of this Appender.
`void`	`setThreshold(Priority threshold)`	Set the threshold level.

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.log4j.Appender
close, requiresLayout

- Field Detail
  - layout
```
protected Layout layout
```
    The layout variable does not need to be set if the appender implementation has its own layout.
  - name
```
protected java.lang.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 Detail
  - 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 Detail
  - 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 java.lang.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 java.lang.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(java.lang.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

Modifier	Constructor	Description
	`AppenderSkeleton()`	Create new instance.
`protected`	`AppenderSkeleton(boolean isActive)`	Create new instance.

Class AppenderSkeleton

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.log4j.Appender

Field Detail

layout

name

threshold

errorHandler

headFilter

tailFilter

closed

Constructor Detail

AppenderSkeleton

AppenderSkeleton

Method Detail

activateOptions

addFilter

append

clearFilters

finalize

getErrorHandler

getFilter

getFirstFilter

getLayout

getName

getThreshold

isAsSevereAsThreshold

doAppend

setErrorHandler

setLayout

setName

setThreshold