ClientListener

Event handler that receives a notification when the ClientListener instance is removed from a LightstreamerClient through LightstreamerClient#removeListener. This is the last event to be fired on the listener.

Event handler that receives a notification when the ClientListener instance is added to a LightstreamerClient through LightstreamerClient#addListener. This is the first event to be fired on the listener.

Event handler that receives a notification each time the value of a property of LightstreamerClient#connectionDetails or LightstreamerClient#connectionOptions is changed.
Properties of these objects can be modified by direct calls to them, but also by calls performed on other LightstreamerClient instances sharing the same connection and by server sent events.

Event handler that is called when the Server notifies a refusal on the client attempt to open a new connection or the interruption of a streaming connection. In both cases, the ClientListener#onStatusChange event handler has already been invoked with a "DISCONNECTED" status and no recovery attempt has been performed. By setting a custom handler, however, it is possible to override this and perform custom recovery actions.

Notifies that the Server has sent a keepalive message because a streaming connection is in place and no update had been sent for the configured time (see ConnectionOptions#setKeepaliveInterval). However, note that the lack of both updates and keepalives is already managed by the library (see ConnectionOptions#setReconnectTimeout and ConnectionOptions#setStalledTimeout).

Event handler that receives a notification in case a connection sharing is aborted. A connection sharing can only be aborted if one of the policies specified in the ConnectionSharing instance supplied to the LightstreamerClient#enableSharing method is "ABORT".
If this event is fired the client will never be able to connect to the server unless a new call to enableSharing is issued.

Event handler that receives a notification each time the LightstreamerClient status has changed. The status changes may be originated either by custom actions (e.g. by calling LightstreamerClient#disconnect) or by internal actions.

The normal cases are the following:

• After issuing connect(), if the current status is "DISCONNECTED*", the client will switch to "CONNECTING" first and to "CONNECTED:STREAM-SENSING" as soon as the pre-flight request receives its answer.
  As soon as the new session is established, it will switch to "CONNECTED:WS-STREAMING" if the browser/environment permits WebSockets; otherwise it will switch to "CONNECTED:HTTP-STREAMING" if the browser/environment permits streaming or to "CONNECTED:HTTP-POLLING" as a last resort.
  On the other hand if the status is already "CONNECTED:*" a switch to "CONNECTING" is usually not needed.
• After issuing disconnect(), the status will switch to "DISCONNECTED".
• In case of a server connection refusal, the status may switch from "CONNECTING" directly to "DISCONNECTED". After that, the ClientListener#onServerError event handler will be invoked.

• In case of Server unavailability during streaming, the status may switch from "CONNECTED:*-STREAMING" to "STALLED" (see ConnectionOptions#setStalledTimeout). If the unavailability ceases, the status will switch back to ""CONNECTED:*-STREAMING""; otherwise, if the unavailability persists (see ConnectionOptions#setReconnectTimeout), the status will switch to "DISCONNECTED:TRYING-RECOVERY" and eventually to "CONNECTED:*-STREAMING".
• In case the connection or the whole session is forcibly closed by the Server, the status may switch from "CONNECTED:*-STREAMING" or "CONNECTED:*-POLLING" directly to "DISCONNECTED". After that, the ClientListener#onServerError event handler will be invoked.
• Depending on the setting in ConnectionOptions#setSlowingEnabled, in case of slow update processing, the status may switch from "CONNECTED:WS-STREAMING" to "CONNECTED:WS-POLLING" or from "CONNECTED:HTTP-STREAMING" to "CONNECTED:HTTP-POLLING".
• If the status is "CONNECTED:*-POLLING" and any problem during an intermediate poll occurs, the status may switch to "CONNECTING" and eventually to "CONNECTED:*-POLLING". The same may hold for the "CONNECTED:*-STREAMING" case, when a rebind is needed.
• In case a forced transport was set through ConnectionOptions#setForcedTransport, only the related final status or statuses are possible.
• In case of connection problems, the status may switch from any value to "DISCONNECTED:WILL-RETRY" (see ConnectionOptions#setRetryDelay), then to "CONNECTING" and a new attempt will start. However, in most cases, the client will try to recover the current session; hence, the "DISCONNECTED:TRYING-RECOVERY" status will be entered and the recovery attempt will start.
• In case of connection problems during a recovery attempt, the status may stay in "DISCONNECTED:TRYING-RECOVERY" for long time, while further attempts are made. If the recovery is no longer possible, the current session will be abandoned and the status will switch to "DISCONNECTED:WILL-RETRY" before the next attempts.
• In case the local LightstreamerClient is exploiting the connection of a different LightstreamerClient (see ConnectionSharing) and such LightstreamerClient or its container window is disposed, the status will switch to "DISCONNECTED:WILL-RETRY" unless the current status is "DISCONNECTED". In the latter case it will remain "DISCONNECTED".

By setting a custom handler it is possible to perform actions related to connection and disconnection occurrences. Note that LightstreamerClient#connect and LightstreamerClient#disconnect, as any other method, can be issued directly from within a handler.