Package it.polimi.ingsw.Network

Class KeepAliveSocketWrapper

java.lang.Object

it.polimi.ingsw.Network.SocketWrapper

it.polimi.ingsw.Network.KeepAliveSocketWrapper

public class KeepAliveSocketWrapper
extends SocketWrapper

A SocketWrapper that also takes care of sending or responding to HeartBeatMessage, keeping the connection active so long as the endpoint proves to be active

Field Summary

Fields

Modifier and Type	Field	Description
private final HeartBeatSender	heartBeatSender
private Timer	heartBeatTimer
private final BlockingQueue<Message>	inputQueue
private final long	keepAlivePeriod

Constructor Summary

Constructors

Constructor	Description
KeepAliveSocketWrapper(Socket socket, long keepAlivePeriod, boolean activeHeartBeat)	Wraps the socket around a keep alive wrapper.

Method Summary

Modifier and Type	Method	Description
Message	awaitMessage()	Blocks until a message is read or the heartbeat timeout expires

Methods inherited from class it.polimi.ingsw.Network.SocketWrapper

close, getInetAddress, isClosed, sendMessage

Methods inherited from class java.lang.Object

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

Field Details

inputQueue

private final BlockingQueue<Message> inputQueue

heartBeatSender

private final HeartBeatSender heartBeatSender

keepAlivePeriod

private final long keepAlivePeriod

heartBeatTimer

private Timer heartBeatTimer

Constructor Details

KeepAliveSocketWrapper

public KeepAliveSocketWrapper(Socket socket,
 long keepAlivePeriod,
 boolean activeHeartBeat)
                       throws IOException

Wraps the socket around a keep alive wrapper. The socket can be active or passive, the former means the socket actively sends a HeartBeatMessage at constant intervals, the latter means the socket sends a HeartBeatMessage for every HeartBeatMessage received.
The sockets will automatically close after a timeout, the timeout is 3 times the fixed duration used by an active wrapper to send its heartbeats.
Note: server used wrappers are encouraged to use the passive wrapper while clients are encouraged to use the active version instead.
Note: Assuming both ends of the connection use this wrapper keeping at least one active wrapper either as the client or server will keep the connection alive until an error occurs without the need to manually send the heartbeat. The same can be said if both ends of the connection are active wrappers. The same cannot be said if both ends are passive.

Parameters:

socket - the socket to wrap around

keepAlivePeriod - the time (in milliseconds) it takes for an active wrapper to send a heartbeat and a third of the timeout required to close the connection and deem the endpoint unreachable

activeHeartBeat - if set to true, makes the wrapper send a HeartBeatMessage every period, if set to false makes the HeartBeatMessage be sent only in response to a HeartBeatMessage in input.

Throws:

IOException - if any issues occur while wrapping the socket.

Method Details

awaitMessage

public Message awaitMessage()
                     throws IOException

Blocks until a message is read or the heartbeat timeout expires

Overrides:

awaitMessage in class SocketWrapper

Returns:

the read message

Throws:

IOException - if the timeout runs out or if an error is encountered while fetching a message