Package pl.morgwai.base.servlet.utils

Class WebsocketPingerService

java.lang.Object

pl.morgwai.base.servlet.utils.WebsocketPingerService

public class WebsocketPingerService
extends Object

Automatically pings and handles pongs from websocket connections.

Initial instances are usually created at app startup and stored in a location easily reachable for endpoint instances (for example on static var in app's ServletContextListener). Additional instances may be added later if number of connections is too big to handle for the existing ones.

Endpoint instances should register themselves for pinging in their Endpoint.onOpen(Session, jakarta.websocket.EndpointConfig) method using addConnection(Session) and deregister in Endpoint.onClose(Session, CloseReason) using removeConnection(Session).

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_MAX_MALFORMED_PONG_COUNT	Arbitrarily chosen number.
static int	DEFAULT_PING_INTERVAL	Majority of proxy and NAT routers have timeout of at least 60s.

Constructor Summary

Constructors

Constructor	Description
WebsocketPingerService()	Calls WebsocketPingerService(DEFAULT_PING_INTERVAL, DEFAULT_MAX_MALFORMED_PONG_COUNT).
WebsocketPingerService(int pingIntervalSeconds, int maxMalformedPongCount)	Configures and starts the service.

Method Summary

Modifier and Type	Method	Description
void	addConnection(Session connection)	Registers connection for pinging.
int	getConnectionsSize()	Returns the number of currently registered connections.
void	removeConnection(Session connection)	Deregisters connection.
ConcurrentMap<Session,pl.morgwai.base.servlet.utils.WebsocketPingerService.PingPongPlayer>	stop()	Stops the service.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PING_INTERVAL

public static final int DEFAULT_PING_INTERVAL

Majority of proxy and NAT routers have timeout of at least 60s.

See Also:

Constant Field Values

DEFAULT_MAX_MALFORMED_PONG_COUNT

public static final int DEFAULT_MAX_MALFORMED_PONG_COUNT

Arbitrarily chosen number.

See Also:

Constant Field Values

Constructor Detail

WebsocketPingerService

public WebsocketPingerService(int pingIntervalSeconds,
                              int maxMalformedPongCount)

Configures and starts the service.

Parameters:

pingIntervalSeconds - how often to ping all connections.

maxMalformedPongCount - limit after which a given connection is closed. Each valid, timely pong resets connection's counter. Pongs received after pingIntervalSeconds count as malformed.

WebsocketPingerService

public WebsocketPingerService()

Calls WebsocketPingerService(DEFAULT_PING_INTERVAL, DEFAULT_MAX_MALFORMED_PONG_COUNT).

Method Detail

addConnection

public void addConnection(Session connection)

Registers connection for pinging. Usually called in Endpoint.onOpen(Session, jakarta.websocket.EndpointConfig).

removeConnection

public void removeConnection(Session connection)

Deregisters connection. Usually called in Endpoint.onClose(Session, CloseReason).

getConnectionsSize

public int getConnectionsSize()

Returns the number of currently registered connections.

stop

public ConcurrentMap<Session,pl.morgwai.base.servlet.utils.WebsocketPingerService.PingPongPlayer> stop()

Stops the service. After a call to this method the service becomes no longer usable and should be discarded.

Returns:

remaining registered connections.