In a UML class diagram, the value of one of the attributes of a class is a (typed) dictionary. What is a proper UML type annotation? (Within the box; not as an association.)
For example, in Python I would annotate this attribute with Dict[A,B] or possibly Mapping[A,B]. I am not asking about Python; this is just one example of a somewhat generic attribute annotation. I am open to the possibility that UML does not offer a language agnostic equivalent to this, but I am hoping that is not true.
Comment: I am asking about generic attribute annotation, directly with the class box. I do not wish to add a separate class box for Dict to the diagram. Therefore this is not a duplicate of How can I represent a Python dictionary in UML?
In UML Dict is typically model as a template class with two template parameters for instance named key and value.
Let's say you want the class C has the attribute a being a Dict[A,B], so you have a binding having the template param substitutions key -> A and value -> B.
There are several ways to show that in a class diagram.
For instance using the class DictAB to model Dict[A,B] :
or if you prefer :
But it is also possible to not use the auxiliary class DictAB and to use the textual representation of the binding expression (see formal/2017-12-05 § 7.3.4 page 26) :
Related
I'd like to know if it is correct to add an Association Class to a Composition relationship?
For example (see figure below), can I add an Association Class (i.e. NameValue class) to the composition relationship between Name class and Value class? One Name can have multiple Value and one Value can only be attached to one Name. NameValue class stores the name-value pairs.
The reason why I create the association class (i.e. NameValue class) is that I need to create associations/relationships between NameValue class and other classes such as Class A.
If the answer is yes, is it recommended to turn the association class into a normal class?
Many thanks!
I'd like to know if it is correct to add an Association Class to a Composition relationship?
yes in an association-class the association can have an owner-end property being a composition, in formal/2017-12-05 there is nothing in § 11.5.3.2 Association Classes starting page 200 nor in § 11.8.2 AssociationClass [Class] against that even association-class has some constraints
NameValue class stores the name-value pairs.
note this is absolutely not the goal of the class of an association-class in UML, and not necessary the case when you implement an association-class
The reason why I create the association class (i.e. NameValue class) is that I need to create associations/relationships between NameValue class and other classes such as Class A
because NameValue is used at implementation level to stores the name-value pairs and then to implement the association(-class), in UML the diagram you want is :
(NameValue does not exist at UML level but only at implementation level)
If the answer is yes, is it recommended to turn the association class into a normal class?
At UML level the association-class do not exist for nothing, they make the model clear, so I do not recommend to not use class-association (but this is of course opinion-based)
Using this tool the classes corresponding to my code were created.
Each class has attributes with its getter and setter methods.
The attributes are created in the diagram but with the label << Property >> Without the corresponding methods, as you can see from the image.
Moreover, lists are not attributed to the type List , even if I change the association into aggregation.
The label << Property >> tells you precisely an attribute which correspond getter and setter?
I could not find anything about this label in the UML documentation
What you call label is a stereotype. Attributes with a <<Property>> stereotype are usually marked this way to tell a code generator that appropriate getter and setter methods shall be created if the target language supports (or requires) that.
Lists do not depend on the composition symbol but on the multiplicity which is barely readable, but I guess the dots near the associations are asterisks (for any multiplicity). The dots at the end of the associations are isOwned attributes (saying the the dot-marked class owns the association).
I want to write a class diagram for a class that contains a hashmap.
Normally, I would do this:
But my Map looks like this:
private Map<Beacon, String> beaconRoute;
The key is a custom class.
How can I describe it in an UML diagram?
Use beacon : Beacon inside the qualifier rectangle and use the String data type as the target type (instead of Employee). The property beaconRoute is the association end name. You don't have to be so literal as to have a Map class in UML--doing that loses sight of the problem domain. Not that I understand why a Beacon would map to a String, though. Did you reverse the key and value by mistake?
You can use an association class for that:
In UML, I diagram class B extending class A. In my actual class implementation, class B's constructor sets default values for protected members of class A. I know how to diagram default values for a class's owned members, but how do I diagram default values for fields which are not owned by the class?
In other words, how do I diagram default values in class B for fields defined in class A?
(note: I'm unable to change the class structure; I'm only diagramming)
This should be the way:
In order to create the picture I used Sparx Systems Enterprise Architect and the "Features & Properties → Override Attribute Initializers" context menu operation applied to the inherited field1 attribute.
So I think that this notation is correct because:
there is a remarkable tool that supports it
this notation is also used when showing slots in object instances
I'm not aware of any counterargument
You can use redefinition of attribute from class A in class B. Redefinition should set default value in class B. Or you can define instance specification (instance of class B) with slots. Fill slot value of specific attribute in instance of class B.
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.