Package org.apache.logging.log4j.core
Interface Appender
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- All Superinterfaces:
LifeCycle
- All Known Implementing Classes:
AbstractAppender
,AbstractFileAppender
,AbstractOutputStreamAppender
,AbstractWriterAppender
,AppenderAdapter.Adapter
,AsyncAppender
,ConsoleAppender
,CountingNoOpAppender
,FailoverAppender
,FileAppender
,HttpAppender
,MemoryMappedFileAppender
,NullAppender
,OutputStreamAppender
,RandomAccessFileAppender
,RewriteAppender
,RollingFileAppender
,RollingRandomAccessFileAppender
,RoutingAppender
,ScriptAppenderSelector
,SmtpAppender
,SocketAppender
,SyslogAppender
,WriterAppender
public interface Appender extends LifeCycle
AppendsLogEvent
s. An Appender can contain aLayout
if applicable as well as anErrorHandler
. Typical Appender implementations coordinate with an implementation ofAbstractManager
to handle external resources such as streams, connections, and other shared state. As Appenders are plugins, concrete implementations need to be annotated withPlugin
and need to provide a static factory method annotated withPluginFactory
.Most core plugins are written using a related Manager class that handle the actual task of serializing a
LogEvent
to some output location. For instance, many Appenders can take advantage of theOutputStreamManager
class.It is recommended that Appenders don't do any heavy lifting since there can be many instances of the class being used at any given time. When resources require locking (e.g., through
FileLock
), it is important to isolate synchronized code to prevent concurrency issues.
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Nested Class Summary
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Nested classes/interfaces inherited from interface org.apache.logging.log4j.core.LifeCycle
LifeCycle.State
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Field Summary
Fields Modifier and Type Field Description static String
ELEMENT_TYPE
Main plugin element type for Appender plugins.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
append(LogEvent event)
Logs a LogEvent using whatever logic this Appender wishes to use.ErrorHandler
getHandler()
Gets theErrorHandler
used for handling exceptions.Layout<? extends Serializable>
getLayout()
Returns the Layout used by this Appender if applicable.String
getName()
Gets the name of this Appender.boolean
ignoreExceptions()
Some Appenders need to propagate exceptions back to the application.void
setHandler(ErrorHandler handler)
Sets theErrorHandler
used for handling exceptions.
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Field Detail
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ELEMENT_TYPE
static final String ELEMENT_TYPE
Main plugin element type for Appender plugins.- Since:
- 2.6
- See Also:
- Constant Field Values
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Method Detail
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append
void append(LogEvent event)
Logs a LogEvent using whatever logic this Appender wishes to use. It is typically recommended to use a bridge pattern not only for the benefits from decoupling an Appender from its implementation, but it is also handy for sharing resources which may require some form of locking.- Parameters:
event
- The LogEvent.
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getName
String getName()
Gets the name of this Appender.- Returns:
- name, may be null.
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getLayout
Layout<? extends Serializable> getLayout()
Returns the Layout used by this Appender if applicable.- Returns:
- the Layout for this Appender or
null
if none is configured.
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ignoreExceptions
boolean ignoreExceptions()
Some Appenders need to propagate exceptions back to the application. WhenignoreExceptions
isfalse
the AppenderControl will allow the exception to percolate.- Returns:
true
if exceptions will be logged but not thrown,false
otherwise.
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getHandler
ErrorHandler getHandler()
Gets theErrorHandler
used for handling exceptions.- Returns:
- the ErrorHandler for handling exceptions.
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setHandler
void setHandler(ErrorHandler handler)
Sets theErrorHandler
used for handling exceptions.- Parameters:
handler
- the ErrorHandler to use for handling exceptions.
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