org.apache.uima.collection.impl.cpm.container.deployer.vns

Class LocalVNS

java.lang.Object

org.apache.vinci.transport.VinciServableAdapter

org.apache.uima.collection.impl.cpm.container.deployer.vns.LocalVNS

All Implemented Interfaces:

Runnable, org.apache.vinci.transport.TransportableFactory, org.apache.vinci.transport.VinciServable

public class LocalVNS
extends org.apache.vinci.transport.VinciServableAdapter
implements Runnable

LOCAL Vinci Naming Service. Used by locally deployed TAEs. Locally, meaning TAEs running on the same machine but in different JVM. This VNS is primarily used by TAEs to advertise their availability after succesfull startup.

Constructor Summary

Constructors

Constructor and Description
LocalVNS() Instantiates a new local VNS.
LocalVNS(int aStartPort, int aEndPort, int aVNSPort) Initialize local VNS instance with a range of ports, and the port for the VNS itself.
LocalVNS(String aStartPort, String aEndPort, String aVNSPort) Instantiates Local Vinci Naming Service.

Method Summary

Modifier and Type	Method and Description
org.apache.vinci.transport.Transportable	eval(org.apache.vinci.transport.Transportable in) Main method called by services advertising their availability.
protected void	finalize()
int	getPort() Returns the next available port.
int	getVNSPort() Returns the port number on which local VNS is listening for requests.
boolean	isAvailable(int port) Determines if a given port is free.
void	run() Starts VNS thread.
void	setConnectionPool(BoundedWorkQueue pQueue) Associates a port pool with instance of VNS.
void	shutdown() Stop the VNS service.

Methods inherited from class org.apache.vinci.transport.VinciServableAdapter

cleanExit, makeTransportable

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LocalVNS

public LocalVNS()

Instantiates a new local VNS.

LocalVNS

public LocalVNS(String aStartPort,
                String aEndPort,
                String aVNSPort)
         throws PortUnreachableException

Instantiates Local Vinci Naming Service.

Parameters:

aStartPort - - a starting port # for clients (services)

aEndPort - - an ending port # for clients( services)

aVNSPort - - port on which this VNS will listen on

Throws:

PortUnreachableException - the port unreachable exception

LocalVNS

public LocalVNS(int aStartPort,
                int aEndPort,
                int aVNSPort)
         throws PortUnreachableException

Initialize local VNS instance with a range of ports, and the port for the VNS itself. A given port is tested first for availability. If it is not available the next port is tested, until one is found to be available.

Parameters:

aStartPort - - starting port number used

aEndPort - - end port number. Together with StartPort defines the range of ports (port pool)

aVNSPort - - port on which this VNS will listen for requests

Throws:

PortUnreachableException - unreachable port after retries

Method Detail

setConnectionPool

public void setConnectionPool(BoundedWorkQueue pQueue)

Associates a port pool with instance of VNS.

Parameters:

pQueue - - queue where allocated ports will be added

isAvailable

public boolean isAvailable(int port)

Determines if a given port is free. It establishes a short lived connection to the port and if successful returns false.

Parameters:

port - number to check

Returns:

true, if is available

getVNSPort

public int getVNSPort()

Returns the port number on which local VNS is listening for requests.

Returns:

- VNS port number

getPort

public int getPort()
            throws PortUnreachableException

Returns the next available port. The port is allocated from a cache of ports given to the VNS service on startup.

Returns:

- free port

Throws:

PortUnreachableException - can't get port in configured range

eval

public org.apache.vinci.transport.Transportable eval(org.apache.vinci.transport.Transportable in)
                                              throws org.apache.vinci.transport.ServiceException

Main method called by services advertising their availability. Each service, on startup sends "serveon" request to VNS and waits for assigned port. The VNS looks up its cahce of ports and returns to the service one that has not yest allocated.

Specified by:

eval in interface org.apache.vinci.transport.VinciServable

Specified by:

eval in class org.apache.vinci.transport.VinciServableAdapter

Parameters:

in - the in

Returns:

the transportable

Throws:

org.apache.vinci.transport.ServiceException - the service exception

shutdown

public void shutdown()

Stop the VNS service.

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

run

public void run()

Starts VNS thread. This thread runs continuously waiting for service registrations and returning port number back.

Specified by:

run in interface Runnable