Examples of org.tanukisoftware.wrapper.WrapperActionServer

• org.tanukisoftware.wrapper.WrapperActionServer
  If an application instantiates an instance of this class, the JVM will listen on the specified port for connections. When a connection is detected, the first byte of input will be read from the socket and then the connection will be immediately closed. An action will then be performed based on the byte read from the stream.

  The easiest way to invoke an action manually is to telnet to the specified port and then type the single command key. telnet localhost 9999, for example.

  Valid commands include:

  • S : Shutdown cleanly.
  • H : Immediate forced shutdown.
  • R : Restart
  • D : Perform a Thread Dump
  • U : Unexpected shutdown. (Simulate a crash for testing)
  • V : Cause an access violation. (For testing)
  • G : Make the JVM appear to be hung. (For testing)

  Additional user defined actions can be defined by calling the {@link #registerAction(byte command,Runnable action)} method.The Wrapper project reserves the right to define any upper case commands in the future. To avoid future conflicts, please use lower case for user defined commands.

  This application will work even in most deadlock situations because the thread is in issolation from the rest of the application. If the JVM is truely hung, this class will fail to accept connections but the Wrapper itself will detect the hang and restart the JVM externally.

  The following code can be used in your application to start up the WrapperActionServer with all default actions enabled:

   int port = 9999; WrapperActionServer server = new WrapperActionServer( port ); server.enableShutdownAction( true ); server.enableHaltExpectedAction( true ); server.enableRestartAction( true ); server.enableThreadDumpAction( true ); server.enableHaltUnexpectedAction( true ); server.enableAccessViolationAction( true ); server.enableAppearHungAction( true ); server.start(); 

  Then remember to stop the server when your application shuts down:

   server.stop(); 

  @author Leif Mortenson

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