I currently doing some model transformations using EMF-UML-Implementation. In my model transformation I create an uml class with some attributes. The attributes are type of enumerations I also created. Some of the attribute should get a default value. The default value should be enumeration literals.
The question now is, how do I get the enumeration literals to the defaultValue-property of the Property.
I already have found that I have to use ValueSpecification. But the UML superstructure says not much about that (page 139 f.). Which properties do I have to use for setting the defaultValue to enumeration literals?
I think the main problem I have is, that the use of ValueSpecification is unclear to me. Currently I only use default to set the default values, which is type of String.
The defaultValue-property takes a ValueSpecification argument. So in your case, you need an InstanceValue for this purpose (which derives from ValueSpecification). The InstanceValue itself has an instance-property, which takes an InstanceSpecification as argument. As EnumerationLiteral derives from InstanceSpecification, you can now simply assign one of your EnumerationLiterals to it.
来源：https://stackoverflow.com/questions/11989969/how-to-specifiy-enumeration-literal-as-default-value-in-uml-attribute