org.apache.log4j.net
Class SocketHubAppender

java.lang.Object
  extended by org.apache.log4j.AppenderSkeleton
      extended by org.apache.log4j.net.SocketHubAppender
All Implemented Interfaces:
Appender, OptionHandler

public class SocketHubAppender
extends AppenderSkeleton

Sends LoggingEvent objects to a set of remote log servers, usually a SocketNodes.

Acts just like SocketAppender except that instead of connecting to a given remote log server, SocketHubAppender accepts connections from the remote log servers as clients. It can accept more than one connection. When a log event is received, the event is sent to the set of currently connected remote log servers. Implemented this way it does not require any update to the configuration file to send data to another remote log server. The remote log server simply connects to the host and port the SocketHubAppender is running on.

The SocketHubAppender does not store events such that the remote side will events that arrived after the establishment of its connection. Once connected, events arrive in order as guaranteed by the TCP protocol.

This implementation borrows heavily from the SocketAppender.

The SocketHubAppender has the following characteristics:

Author:
Mark Womack

Field Summary
static String ZONE
          The MulticastDNS zone advertised by a SocketHubAppender
 
Fields inherited from class org.apache.log4j.AppenderSkeleton
closed, errorHandler, headFilter, layout, name, tailFilter, threshold
 
Constructor Summary
SocketHubAppender()
           
SocketHubAppender(int _port)
          Connects to remote server at address and port.
 
Method Summary
 void activateOptions()
          Set up the socket server on the specified port.
 void append(LoggingEvent event)
          Append an event to all of current connections.
 void cleanUp()
          Release the underlying ServerMonitor thread, and drop the connections to all connected remote servers.
 void close()
          Close this appender.
protected  ServerSocket createServerSocket(int socketPort)
          Creates a server socket to accept connections.
 String getApplication()
          Returns value of the Application option.
 int getBufferSize()
          Returns value of the bufferSize option.
 boolean getLocationInfo()
          Returns value of the LocationInfo option.
 int getPort()
          Returns value of the Port option.
 boolean isAdvertiseViaMulticastDNS()
           
 boolean requiresLayout()
          The SocketHubAppender does not use a layout.
 void setAdvertiseViaMulticastDNS(boolean advertiseViaMulticastDNS)
           
 void setApplication(String lapp)
          The App option takes a string value which should be the name of the application getting logged.
 void setBufferSize(int _bufferSize)
          The BufferSize option takes a positive integer representing the number of events this appender will buffer and send to newly connected clients.
 void setLocationInfo(boolean _locationInfo)
          The LocationInfo option takes a boolean value.
 void setPort(int _port)
          The Port option takes a positive integer representing the port where the server is waiting for connections.
 
Methods inherited from class org.apache.log4j.AppenderSkeleton
addFilter, clearFilters, doAppend, finalize, getErrorHandler, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setErrorHandler, setLayout, setName, setThreshold
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

ZONE

public static final String ZONE
The MulticastDNS zone advertised by a SocketHubAppender

See Also:
Constant Field Values
Constructor Detail

SocketHubAppender

public SocketHubAppender()

SocketHubAppender

public SocketHubAppender(int _port)
Connects to remote server at address and port.

Method Detail

activateOptions

public void activateOptions()
Set up the socket server on the specified port.

Specified by:
activateOptions in interface OptionHandler
Overrides:
activateOptions in class AppenderSkeleton

close

public void close()
Close this appender.

This will mark the appender as closed and call then cleanUp() method.


cleanUp

public void cleanUp()
Release the underlying ServerMonitor thread, and drop the connections to all connected remote servers.


append

public void append(LoggingEvent event)
Append an event to all of current connections.

Specified by:
append in class AppenderSkeleton

requiresLayout

public boolean requiresLayout()
The SocketHubAppender does not use a layout. Hence, this method returns false.


setPort

public void setPort(int _port)
The Port option takes a positive integer representing the port where the server is waiting for connections.


setApplication

public void setApplication(String lapp)
The App option takes a string value which should be the name of the application getting logged. If property was already set (via system property), don't set here.


getApplication

public String getApplication()
Returns value of the Application option.


getPort

public int getPort()
Returns value of the Port option.


setBufferSize

public void setBufferSize(int _bufferSize)
The BufferSize option takes a positive integer representing the number of events this appender will buffer and send to newly connected clients.


getBufferSize

public int getBufferSize()
Returns value of the bufferSize option.


setLocationInfo

public void setLocationInfo(boolean _locationInfo)
The LocationInfo option takes a boolean value. If true, the information sent to the remote host will include location information. By default no location information is sent to the server.


getLocationInfo

public boolean getLocationInfo()
Returns value of the LocationInfo option.


setAdvertiseViaMulticastDNS

public void setAdvertiseViaMulticastDNS(boolean advertiseViaMulticastDNS)

isAdvertiseViaMulticastDNS

public boolean isAdvertiseViaMulticastDNS()

createServerSocket

protected ServerSocket createServerSocket(int socketPort)
                                   throws IOException
Creates a server socket to accept connections.

Parameters:
socketPort - port on which the socket should listen, may be zero.
Returns:
new socket.
Throws:
IOException - IO error when opening the socket.


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