Custom object and type instance with attribute delegate

[rich0rd]

Hy,

I was playing with the server example of milo, more precisely with the addCustomObjectTypeAndInstance” method. (https://github.com/eclipse/milo/blob/c77d06a4d7ccfe408c3e931e15700f53c42a8f8d/milo-examples/server-examples/src/main/java/org/eclipse/milo/examples/server/ExampleNamespace.java#L540)

In my example my object nodes should have user access level AccessLevel.CurrentRead, AccessLevel.HistoryRead and an attribute delegate for reading requests.
In the milo server example, the object node is created comfortable by the node factory. But neither the user access level nor the attribute delegate is set/copied in the created object node. I’m new to milo and could not access if the node factory should do this. But who can I access the created child nodes of my object node to set these attributes?

        // Use NodeFactory to create instance of MyObjectType called "MyObject".
        // NodeFactory takes care of recursively instantiating MyObject member nodes
        // as well as adding all nodes to the address space.
        UaObjectNode myObject = nodeFactory.createObject(
            new NodeId(namespaceIndex, "HelloWorld/MyObject"),
            new QualifiedName(namespaceIndex, "MyObject"),
            LocalizedText.english("MyObject"),
            objectTypeNode.getNodeId()
      );

      //how to create AccessLevel.CurrentRead, AccessLevel.HistoryRead and an attribute delegate 
      //for "foo" and "bar" node???

Many thanks,

[Dalaitama]

Hallo

IMHO, i’m not 100% sure but an attribute delegate doesn’t belong to an Instance Definition, it belongs to the ObjectNode which will be instantiated later. I didn’t find out which member are applied on the ObjectNode created on cascade from the nodeFactory, but an AttributeDelegate if set on the InstanceDefinition, will not work on the instance. You have to set it after the object creation, on the real instance.

I assume this is not a Bug (may be I am wrong) but to me could make sense, since if you create 3 instances of a NodeType with the Node Factory (and its components, aka InstanceDefinitions) , then I think you should set there attribute delegate. Hence it will not make sense to have in the same server 3 Attribute Delegate which potentially access the same data.

Make sense ? @kevinherron , i am in a wrong way? or it is simply that the attribute Delegate it is not a standard construct ?

Thanks Lorenzo

[kevinherron]

Yes, that's correct, you would not put a delegate onto the definition for your custom type. It belongs on an instance.

Further, AccessLevel is an Attribute that belongs to a VariableNode, not and ObjectNode, which is why you aren't able to configure it.

On Mon, Mar 19, 2018 at 5:15 AM, Dalaitama notifications@github.com wrote:

Hallo

IMHO, i’m not 100% sure but an attribute delegate doesn’t belong to an Instance Definition, it belongs to the ObjectNode which will be instantiated later. I didn’t find out which member are applied on the ObjectNode created on cascade from the nodeFactory, but an AttributeDelegate if set on the InstanceDefinition, will not work on the instance. You have to set it after the object creation, on the real instance.

I assume this is not a Bug (may be I am wrong) but to me could make sense, since if you create 3 instances of a NodeType with the Node Factory (and its components, aka InstanceDefinitions) , then I think you should set there attribute delegate. Hence it will not make sense to have in the same server 3 Attribute Delegate which potentially access the same data.

Make sense ? @kevinherron https://github.com/kevinherron , i am in a wrong way?

Thanks Lorenzo

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[rich0rd]

Many thanks for the quick response. Of course the AccessLevel belongs to the VaribleNode but even if I set the AccessLevel on "foo" and "bar", the node factory does not assign the property to the object node. See: https://github.com/eclipse/milo/blob/c77d06a4d7ccfe408c3e931e15700f53c42a8f8d/opc-ua-sdk/sdk-server/src/main/java/org/eclipse/milo/opcua/sdk/server/nodes/NodeFactory.java#L196

[kevinherron]

Sorry, I misunderstood your issue originally.

[kevinherron]

Ok, it's a little more complicated. VariableTypeNodes don't have AccessLevel and UserAccessLevel attributes, which is why they aren't "inherited" or assigned when building an instance.

The "fix" for this is going to require some work I'm planning on the 0.3 branch, which is to allow some kind of interceptor/visitor to be installed on the factory that gets called/notified at various stages of construction of a complex node hierarchy. In this case, the way it might work is you'd get a call that provided you the parent node and the newly instantiated child node and you'd have an opportunity to do anything you wish with that information, such as set an AccessLevel on the node, or instantiate some type of object(s) specific to your application that the node represents, etc...