org.apache.log4j

Class AsyncAppender

public class AsyncAppender extends AppenderSkeleton implements AppenderAttachable

The AsyncAppender lets users log events asynchronously.

The AsyncAppender will collect the events sent to it and then dispatch them to all the appenders that are attached to it. You can attach multiple appenders to an AsyncAppender.

The AsyncAppender uses a separate thread to serve the events in its buffer.

Important note: The AsyncAppender can only be script configured using the DOMConfigurator.

Since: 0.9.1

Author: Ceki Gülcü Curt Arnold

Field Summary
static intDEFAULT_BUFFER_SIZE
The default buffer size is set to 128 events.
Constructor Summary
AsyncAppender()
Create new instance.
Method Summary
voidaddAppender(Appender newAppender)
Add appender.
voidappend(LoggingEvent event)
voidclose()
Close this AsyncAppender by interrupting the dispatcher thread which will process all pending events before exiting.
EnumerationgetAllAppenders()
Get iterator over attached appenders.
AppendergetAppender(String name)
Get appender by name.
booleangetBlocking()
Gets whether appender should block calling thread when buffer is full.
intgetBufferSize()
Gets the current buffer size.
booleangetLocationInfo()
Gets whether the location of the logging request call should be captured.
booleanisAttached(Appender appender)
Determines if specified appender is attached.
voidremoveAllAppenders()
Removes and closes all attached appenders.
voidremoveAppender(Appender appender)
Removes an appender.
voidremoveAppender(String name)
Remove appender by name.
booleanrequiresLayout()
voidsetBlocking(boolean value)
Sets whether appender should wait if there is no space available in the event buffer or immediately return.
voidsetBufferSize(int size)
Sets the number of messages allowed in the event buffer before the calling thread is blocked (if blocking is true) or until messages are summarized and discarded.
voidsetLocationInfo(boolean flag)
The LocationInfo option takes a boolean value.

Field Detail

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE
The default buffer size is set to 128 events.

Constructor Detail

AsyncAppender

public AsyncAppender()
Create new instance.

Method Detail

addAppender

public void addAppender(Appender newAppender)
Add appender.

Parameters: newAppender appender to add, may not be null.

append

public void append(LoggingEvent event)
{@inheritDoc }

close

public void close()
Close this AsyncAppender by interrupting the dispatcher thread which will process all pending events before exiting.

getAllAppenders

public Enumeration getAllAppenders()
Get iterator over attached appenders.

Returns: iterator or null if no attached appenders.

getAppender

public Appender getAppender(String name)
Get appender by name.

Parameters: name name, may not be null.

Returns: matching appender or null.

getBlocking

public boolean getBlocking()
Gets whether appender should block calling thread when buffer is full. If false, messages will be counted by logger and a summary message appended after the contents of the buffer have been appended.

Returns: true if calling thread will be blocked when buffer is full.

getBufferSize

public int getBufferSize()
Gets the current buffer size.

Returns: the current value of the BufferSize option.

getLocationInfo

public boolean getLocationInfo()
Gets whether the location of the logging request call should be captured.

Returns: the current value of the LocationInfo option.

isAttached

public boolean isAttached(Appender appender)
Determines if specified appender is attached.

Parameters: appender appender.

Returns: true if attached.

removeAllAppenders

public void removeAllAppenders()
Removes and closes all attached appenders.

removeAppender

public void removeAppender(Appender appender)
Removes an appender.

Parameters: appender appender to remove.

removeAppender

public void removeAppender(String name)
Remove appender by name.

Parameters: name name.

requiresLayout

public boolean requiresLayout()
{@inheritDoc }

setBlocking

public void setBlocking(boolean value)
Sets whether appender should wait if there is no space available in the event buffer or immediately return.

Parameters: value true if appender should wait until available space in buffer.

setBufferSize

public void setBufferSize(int size)
Sets the number of messages allowed in the event buffer before the calling thread is blocked (if blocking is true) or until messages are summarized and discarded. Changing the size will not affect messages already in the buffer.

Parameters: size buffer size, must be positive.

setLocationInfo

public void setLocationInfo(boolean flag)
The LocationInfo option takes a boolean value. By default, it is set to false which means there will be no effort to extract the location information related to the event. As a result, the event that will be ultimately logged will likely to contain the wrong location information (if present in the log format).

Location information extraction is comparatively very slow and should be avoided unless performance is not a concern.

Parameters: flag true if location information should be extracted.

Copyright 2000-2005 Apache Software Foundation.