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public interface UaView
Each View defines a subset of the Nodes in the AddressSpace. The entire AddressSpace is the default View. Each Node in a View may contain only a subset of its References, as defined by the creator of the View. The View Node acts as the root for the Nodes in the View.
All Nodes contained in a View shall be accessible starting from the View Node when browsing in the context of the View. The browse may take several hops, i.e. it is not necessary that all containing Nodes can be browsed directly from the View Node.
A View Node may not only be used as additional entry point into the AddressSpace but as a construct to organize the AddressSpace and thus as the only entry point into a subset of the AddressSpace. Therefore clients shall not ignore View Nodes when exposing the AddressSpace. Simple clients that do not deal with Views for filtering purposes can for example handle a View Node like an Object of type FolderType.
The mandatory ContainsNoLoops Attribute is set to false if the server is not able to identify if the View contains loops or not.
The mandatory EventNotifier Attribute identifies if the View can be used to subscribe to Events that either occur in the content of the View or as ModelChangeEvents of the content of the View or to read / write the history of the Events. A View that supports Events shall provide all Events that occur in any Object used as EventNotifier that is part of the content of the View. In addition, it shall provide all ModelChangeEvents that occur in the context of the View.
To avoid recursion, i.e. getting all Events of the Server, the Server Object shall never be part of any View since it provides all Events of the Server.
Views are defined by the server. The browsing and querying Services expect the NodeId of a View Node to provide these Services in the context of the View.
(OPC UA Specification, Part 3.)
UaObject,
UaVariable,
UaType,
UaClientReference| Method Summary | |
|---|---|
Boolean |
getContainsNoLoops()
If set to true this Attribute indicates that following References in the context
of the View contains no loops, i.e. starting from a Node 'A' contained in the View and
following the forward References in the context of the View Node 'A' will not be reached again. |
EnumSet<EventNotifierClass> |
getEventNotifier()
Defines whether the node can be used to subscribe to events. |
UaProperty |
getViewVersion()
The version number for the View. |
void |
setContainsNoLoops(Boolean containsNoLoops)
|
void |
setEventNotifier(EnumSet<EventNotifierClass> eventNotifier)
|
| Method Detail |
|---|
Boolean getContainsNoLoops()
true this Attribute indicates that following References in the context
of the View contains no loops, i.e. starting from a Node 'A' contained in the View and
following the forward References in the context of the View Node 'A' will not be reached again.
It does not specify that there is only one path starting from the View Node to reach a Node
contained in the View. If set to false this Attribute indicates that following
References in the context of the View may lead to loops. (OPC UA Specification, Part 3.)
EnumSet<EventNotifierClass> getEventNotifier()
| Value | Description |
|---|---|
| SubscribeToEvents | Indicates if it can be used to subscribe to Events (0 means cannot be used to subscribe to Events, 1 means can be used to subscribe to Events). |
| HistoryRead | Indicates if the history of the Events is readable (0 means not readable, 1 means readable). |
| HistoryWrite | Indicates if the history of the Events is writable (0 means not writable, 1 means writable). |
UaProperty getViewVersion()
void setContainsNoLoops(Boolean containsNoLoops)
containsNoLoops - the value of containsNoLoops to setgetContainsNoLoops()void setEventNotifier(EnumSet<EventNotifierClass> eventNotifier)
eventNotifier - the value of Eventnotifier to setgetEventNotifier()
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