Enum in InputArgument with DataTypeDefinition = null

[an-nie]

Hi!

I want to call method GenerateFileForRead. This is the InputArgument:

StructureDefinition[
	defaultEncodingId=NodeId{ns=3, id=5012}, 
	baseDataType=NodeId{ns=0, id=22}, 
	structureType=Structure, 
	fields=[
		StructureField[
			name='Storage', 
			description=LocalizedText[locale=, text=Indication from where the production dataset is read], 
			dataType=NodeId{ns=3, id=3005}, 
			valueRank=-1, 
			arrayDimensions=null, 
			maxStringLength=0, 
			isOptional=false
		], 
		StructureField[
			name='Name', 
			description=LocalizedText[locale=, text=Name of the production dataset that should be transferred from the server to the client], 
			dataType=NodeId{ns=0, id=12}, 
			valueRank=-1, 
			arrayDimensions=null, 
			maxStringLength=0, 
			isOptional=false
		]
	]
]

The problem is constructing an Enum value for the field 'Storage'.

Here is what I do (Scala code, but should be self-explanatory):

val inputStructureDef: StructureDefinition = ... // StructureDefinition shown above
val storageDataTypeNodeId: NodeId = inputStructureDef.getFields.toList.find(_.getName == "Storage").get.getDataType
val storageDataType: DataType = client.getDataTypeTree.getDataType(storageDataTypeNodeId)
val storage = new DynamicEnumType(storageDataType, 1)

This fails in the last line, since on this particular server, storageDataType.dataTypeDefinition is null.

I am unsure how to proceed.

Is this a server issue, do I need to contact the vendor? The NamespaceVersion on the server is 1.04.

If it is not – is there another way to create a DynamicEnumType, one that doesn't require a DataTypeDefinition?

[kevinherron]

Can you browse Types > DataTypes > Enumeration in that server with something like UaExpert and find the DataType Node for this enum? Does it have a DataTypeDefinition/EnumDefinition value?

[kevinherron]

Ok, so this server either doesn't support the OPC UA 1.04 DataTypeDefinition attribute at all, or it's just broken with this enum type.

Try using an Int32 for the enum instead of using DynamicEnumType.

[an-nie]

val method = client.getAddressSpace.getObjectNode(productionDatasetTransferNode)
	.getMethod(new QualifiedName(0, "GenerateFileForRead"))
val inputDataTypeNodeId = method.getInputArguments.head.getDataType
val inputDataType = client.getDataTypeTree.getDataType(inputDataTypeNodeId)
val members: java.util.LinkedHashMap[String, java.lang.Object] = new java.util.LinkedHashMap[String, java.lang.Object]()
members.put("Storage", java.lang.Integer.valueOf(1))
members.put("Name", null)
val input = new DynamicStructType(inputDataType, members)
ExtensionObject.encode(client.getDynamicEncodingContext, input) // fails

Error message:

java.lang.ClassCastException: class java.lang.Integer cannot be cast to class org.eclipse.milo.opcua.stack.core.types.UaEnumeratedType

I have tried UInt und UShort as well, with the same result. It seems like the Argument type (inputDataType) expects an object of type Enum for its first argument, and that object cannot be created without its Enum DataType, which is missing its DataTypeDefinition.

(For context, this issue does seem vendor-specific. I have checked two other servers that implement this specification. The server from the same company as this one also has no DataTypeDefinitions; the server from another company does, and the original code, with the DynamicEnum, works fine.)

[kevinherron]

Ah, I missed that the input argument was a structure containing the enumeration as a member - I thought the enumeration was its own input argument.

In that case, you might get away with instantiating an anonymous UaEnumeratedType rather than the Int32 I suggested...

    var enumValue = new UaEnumeratedType() {
      @Override
      public int getValue() {
        return 0; // enum value
      }

      @Override
      public ExpandedNodeId getTypeId() {
        return ExpandedNodeId.parse(""); // ExpandedNodeId of enum DataType node
      }
    };

Maybe...

[an-nie]

It worked! Thank you for your quick help!

For completeness' sake, I want to mention that before we upgraded to Milo 1.1.0, the following code worked in Milo 0.6.8:

val method = client.getAddressSpace.getObjectNode(datasetTransferNode)
	.getMethod(new QualifiedName(0, "GenerateFileForRead"))
val inputDataType = method.getInputArguments.head.getDataType
val tree: DataTypeTree = DataTypeTreeBuilder.build(client)
val encodingId = tree.getBinaryEncodingId(inputDataType)
val struct = Struct.builder("ProductionDatasetReadOptionsType")
	.addMember("Storage", Unsigned.ushort(1))
	.addMember("Name", null)
	.build()
val encoded = ExtensionObject.encodeDefaultBinary(client.getDynamicSerializationContext, struct, encodingId)

Now we found a way to make it work in 1.1.0, so for now it seems like there is no loss of functionality in the upgrade, but it might be worth keeping an eye out. I cannot gauge how reliable our solution is for other cases of missing DataTypeDefinitions and the like.

And again, thank you!

[kevinherron]

The reason for the change is because in 0.6.x you would have been using the legacy DataType dictionary mechanism for defining/discovering custom types, and now in 1.x you're using the DataTypeDefinition attribute that was introduced in OPC UA 1.04 to replace it.

Most of your servers seem to work, but you have one that either doesn't support it at all or has this misconfigured enum DataType Node.