edu.cuny.cat.comm
Class ListenableConnection<M extends Message>

java.lang.Object
  edu.cuny.cat.comm.ListenableConnection<M>

Type Parameters:

M - the type of messages that can be transmitted through the connection.

All Implemented Interfaces:

Connection<M>, ReactiveConnection<M>, java.lang.Runnable

public class ListenableConnection<M extends Message>
extends java.lang.Object
implements java.lang.Runnable, ReactiveConnection<M>

The class wraps the usual querying-based Connection to support actively pushing Message to a listener.

It should be used in the following way:

   Connection<Message> conn;
 
   ...
       
   ReactiveConnection<Message> reactiveConn = ListenableConnection.makeReactiveConnection(conn);
   reactiveConn.setListener(listener);
   reactiveConn.start();
   
   ...
       
   reactiveConn.stop();
   reactiveConn.setListener(null); // (optional) ...
 

Version:

$Revision: 1.4 $

Author:

Jinzhong Niu

Field Summary

protected ProactiveConnection<M>	connection
protected ConnectionListener<M>	listener
protected java.lang.Thread	thread
static long	THREAD_STACK_SIZE
protected static java.lang.ThreadGroup	threadGroup

Constructor Summary

ListenableConnection(ProactiveConnection<M> connection)

Method Summary

void	close() TODO: not safe to simply set listener null.
ConnectionListener<M>	getListener()
java.lang.String	getLocalAddressInfo()
CatpMessage	getMessage()
java.lang.String	getRemoteAddressInfo()
java.lang.Thread	getThread() This is needed only for debug purpose.
boolean	isClosed() checks whether the connection is closed or not.
static <T extends Message> ReactiveConnection<T>	makeReactiveConnection(Connection<T> conn) wraps a ProactiveConnection with ListenableConnection if necessary to make it support registering-and-listening message passing, i.e.
void	open() opens the connection before sending or receiving any message.
void	run() loops to attempt to read messages and notifies the listener of the arrival.
void	sendMessage(M msg) sends a Message through this connection.
void	setListener(ConnectionListener<M> listener)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

THREAD_STACK_SIZE

public static final long THREAD_STACK_SIZE

See Also:

Constant Field Values

listener

protected ConnectionListener<M extends Message> listener

connection

protected ProactiveConnection<M extends Message> connection

thread

protected java.lang.Thread thread

threadGroup

protected static java.lang.ThreadGroup threadGroup

Constructor Detail

ListenableConnection

public ListenableConnection(ProactiveConnection<M> connection)

Method Detail

getMessage

public CatpMessage getMessage()
                       throws CatException

Throws:

CatException

sendMessage

public void sendMessage(M msg)
                 throws CatException

Description copied from interface: Connection

sends a Message through this connection.

Specified by:

sendMessage in interface Connection<M extends Message>

Parameters:

msg - message to be sent.

Throws:

CatException

run

public void run()

loops to attempt to read messages and notifies the listener of the arrival.

Specified by:

run in interface java.lang.Runnable

See Also:

ConnectionListener.messageArrived(Message)

setListener

public void setListener(ConnectionListener<M> listener)

Specified by:

setListener in interface ReactiveConnection<M extends Message>

getListener

public ConnectionListener<M> getListener()

Specified by:

getListener in interface ReactiveConnection<M extends Message>

open

public void open()
          throws ConnectionException

Description copied from interface: Connection

opens the connection before sending or receiving any message.

Specified by:

open in interface Connection<M extends Message>

Throws:

ConnectionException

close

public void close()
           throws ConnectionException

TODO: not safe to simply set listener null.

Specified by:

close in interface Connection<M extends Message>

Throws:

ConnectionException

isClosed

public boolean isClosed()

Description copied from interface: Connection

checks whether the connection is closed or not.

Specified by:

isClosed in interface Connection<M extends Message>

Returns:

true if closed; false otherwise.

getLocalAddressInfo

public java.lang.String getLocalAddressInfo()

Specified by:

getLocalAddressInfo in interface Connection<M extends Message>

Returns:

a string describing the address of the local end of this connection

getRemoteAddressInfo

public java.lang.String getRemoteAddressInfo()

Specified by:

getRemoteAddressInfo in interface Connection<M extends Message>

Returns:

a string describing the address of the remote end of this connection

makeReactiveConnection

public static <T extends Message> ReactiveConnection<T> makeReactiveConnection(Connection<T> conn)

wraps a ProactiveConnection with ListenableConnection if necessary to make it support registering-and-listening message passing, i.e. an instance of ReactiveConnection.

getThread

public java.lang.Thread getThread()

This is needed only for debug purpose.

Returns:

the thread that runs to repeatedly read from the proactive connection and call listener to process messages.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object