Name 

Description 

 

Init 

Called by the Remote Server to provide initialization information to the Data Adapter. The call must not be blocking; any polling cycle or similar must be started in a different thread. If an exception occurs in this method, Lightstreamer Kernel can't complete the startup and must exit. The initialization information can be supplied in different ways, depending on the way the Remote Server is launched.
The call must not be blocking; any polling cycle or similar must be started in a different thread. Any delay in returning from this call will in turn delay the Server initialization. If an exception... more 

 

IsSnapshotAvailable 

Called by Lightstreamer Kernel through the Remote Server to know whether the Data Adapter, after a subscription for an Item, will send some Snapshot Item Events before sending the updates. An Item Snapshot can be represented by zero, one or more Item Events, also depending on the Item type. The decision whether to supply or not to supply Snapshot information is entirely up to the Data Adapter.
The method should be nonblocking. The availability of the snapshot for an Item should be a known architectural property. When the snapshot, though expected, cannot be obtained at subscription time, then it can... more 

 

SetListener 

Called by the Remote Server to provide a listener to receive the Item Events carrying data and asynchronous error notifications for Lightstreamer Kernel. The listener is set before any subscribe is called and is never changed.  

 

Subscribe 

Called by Lightstreamer Remote Server to request data for an Item. If the request succeeds, the Remote Data Adapter can start sending an ItemEvent to the listener for any update of the Item value. Before sending the updates, the Remote Data Adapter may optionally send one or more ItemEvents to supply the current Snapshot.
The general rule to be followed for event dispatching is:  

 

Unsubscribe 

Called by Lightstreamer Kernel through the Remote Server to end a previous request of data for an Item. After the call has returned, no more ItemEvents for the Item should be sent to the listener until requested by a new subscription for the same Item.
The method can be blocking, but, as the Proxy Adapter implements subscribe and unsubscribe asynchronously, subsequent subscribe-unsubscribe-subscribe-unsubscribe requests can still be issued by Lightstreamer Server to the Proxy Adapter. When this happens, the requests may be queued on the Remote Adapter, hence some Subscribe calls may be delayed.