com.lightstreamer.javameclient.midp

Interface ExtendedTableListener

public interface ExtendedTableListener

A fast, though basic, listener interface, which receives notification of data updates and other messages related to a subscribed table. It can be used in place of SimpleTableListener when item and field name information is available (that is, a LiteralBasedProvider or equivalent Metadata Adapter is configured on the Server).
Only notifications of changed field values received from the Server are available. Unchanged fields are just not included in the update representations.
The listener is called directly from the worker threads. The method implementations should be fast and nonblocking. Any slow operations should be enqueued and performed asynchronously.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	UNCHANGED Constant that represents unchanged fields.

Method Summary

Modifier and Type	Method and Description
void	onControlError(int code, java.lang.String msg) Notification that the Server has refused a Subscription request because of the constraints imposed by the Metadata Adapter or by Server configuration.
void	onEndOfSnapshot(java.lang.String item) Notification that no more snapshot events are coming for an item.
void	onRawUpdatesLost(java.lang.String item, int lostUpdates) Notification of one or more updates that were suppressed in the Server because of internal memory limitations.
void	onUnsubscribe() Notification of the unsubscription of all the items in the table.
void	onUpdate(java.lang.String item, ExtendedItemUpdate update) Notification of an update of the values for an item in the associated table.

Field Detail

UNCHANGED

static final java.lang.String UNCHANGED

Constant that represents unchanged fields. Object identity rather than object equality must be tested; a string value of "UNCHANGED" may be a legal value coming from the Data Adapter.

Method Detail

onUpdate

void onUpdate(java.lang.String item,
              ExtendedItemUpdate update)

Notification of an update of the values for an item in the associated table.

Parameters:

item - Name of the item in the Group of items in the table.

update - Object that carries values received from the Server.

See Also:

ExtendedItemUpdate.isReusable()

onEndOfSnapshot

void onEndOfSnapshot(java.lang.String item)

Notification that no more snapshot events are coming for an item. This notification is always received once, when the item is subscribed in DISTINCT or COMMAND mode and the snapshot is requested.

Parameters:

item - Name of the item in the Group of items in the table.

onRawUpdatesLost

void onRawUpdatesLost(java.lang.String item,
                      int lostUpdates)

Notification of one or more updates that were suppressed in the Server because of internal memory limitations. The notification can be sent if the subscription mode is RAW or COMMAND. It can also be sent if the subscription mode is MERGE or DISTINCT and unfiltered dispatching has been requested. In all these cases, an update loss may be unacceptable for the client (in filtered COMMAND mode, this applies to ADD and DELETE events only).

Parameters:

item - Name of the item in the Group of items in the table.

lostUpdates - Number of consecutive lost updates for the item.

onControlError

void onControlError(int code,
                    java.lang.String msg)

Notification that the Server has refused a Subscription request because of the constraints imposed by the Metadata Adapter or by Server configuration. No data for this table will be received. A detailed error code is supplied. Both the error code and the message are received from the Server. In particular:

• A positive error code is issued by the Server after checking the request against the constraints imposed by the Metadata Adapter or by its own configuration. See the text protocol documentation for a reference of the error codes that can be issued in response to a subscription request.
• A zero or negative error code is issued directly by the Metadata Adapter because of capability restrictions that may be applied to the specific user.

Note: if single connection mode is used, this handler is never called; a subscription error would rather cause the ConnectionListener.onServerError(int, java.lang.String) notification to be issued with error code 19 and the whole session request to fail.

Parameters:

code - The detailed error code, as received from the Server. Its meaning depends on Lightstreamer Server or the Metadata Adapter.

msg - An error detail message, sent by Lightstreamer Server or by the Metadata Adapter.

See Also:

LSClient.useSingleConnection(boolean)

onUnsubscribe

void onUnsubscribe()

Notification of the unsubscription of all the items in the table. The unsubscription may be subsequent to an unsubscribeTable call or to the closure of the connection.