org.eclipse.scada.da.core.server

Interface ItemChangeListener

All Known Implementing Classes:

ServerConnectionHandler

public interface ItemChangeListener

Interface for listening to data items

Method Summary

Methods

Modifier and Type	Method and Description
void	dataChanged(String itemId, Variant value, Map<String,Variant> attributes, boolean cache) A change on the data item occurred.
void	subscriptionChanged(String itemId, SubscriptionState subscriptionState) Indicating a change in the item subscription

Method Detail

dataChanged

void dataChanged(String itemId,
               Variant value,
               Map<String,Variant> attributes,
               boolean cache)

A change on the data item occurred.

Parameters:

itemId - The item id that changed

value - The new value, or null if the value did not change

attributes - The attributes that changed, may be null if no attribute change at all

cache - Indicating that the change came from the cache, this means that the change was not triggered by a device and that all attribute where sent, not only the changed ones

subscriptionChanged

void subscriptionChanged(String itemId,
                       SubscriptionState subscriptionState)

Indicating a change in the item subscription

Parameters:

itemId - The item ID that changed

subscriptionState - the new subscription state