The class is the dominant artifact on a class diagram. In
the UML metamodel it is a sub-class of Classifier
and GeneralizableElement
.
A class is represented on a class diagram as a rectangle with three horizontal compartments. The top compartment displays the class name (and stereotype), the second compartment any attributes and the third any operations. The last two compartments may optionally be hidden.
The details tabs that are active for classes are as follows.
ToDoItem
Standard tab.
Properties
See Section 17.5.2, “Class Property Toolbar” and Section 17.5.3, “Property Fields For Class” below.
Documentation
Standard tab. See Section 12.5, “Documentation Tab”.
Style
Standard tab. The tick boxes,
Attributes
and Operations
allow the attributes and operations compartments to be shown (the
default) or hidden.
This is a setting valid for all diagrams that show the class.
The Bounds:
field defines
the bounding box for the package on the diagram.
Source
Standard tab. This contains a template for the class declaration and declarations of associated classes.
Constraints
Standard tab. There are no standard constraints
defined for Class
within the UML
metamodel.
Tagged Values
Standard tab.
In the UML metamodel, Class
has the following
standard tagged values defined.
persistence
(from the
superclass, Classifier
). Values
transitory
, indicating state is
destroyed when an instance is destroyed or
persistent
, marking state is
preserved when an instance is destroyed.
semantics
(from the
superclass, Classifier
). The value is a
specification of the semantics of the
class.
derived
(from the
superclass, ModelElement
). Values
true
, meaning the class is
redundant—it can be formally derived from other
elements, or false
meaning it
cannot.
![]() | Note |
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Derived classes still have their value in analysis to introduce useful names or concepts, and in design to avoid re-computation. |
![]() | Note |
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The UML |
Go
up
Navigate up through the package structure.
Add
attribute
This creates a new attribute (see Section 17.6, “Attribute”) within the class, navigating immediately to the properties tab for that attribute.
Add
operation
This creates a new operation (see Section 17.7, “Operation”) within the class, navigating immediately to the properties tab for that operation.
Add inner
class
This creates a new inner class (which appears on no diagram) within the class. This belongs to the class and is restricted to the namespace of the class. It exactly models the Java concept of inner class. As an inner class it needs no attributes or operations, since it shares those of its owner.
![]() | Note |
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Inner class is not a separate concept in UML. This is a convenient shorthand for creating a class that is restricted to the namespace of its owning class. |
New
class
This creates a new class (which appears on no diagram) within the same namespace as the current class.
Delete
This deletes the class from the model
![]() | Warning |
---|---|
This is a deletion from the model
not just the diagram. To delete a class
from the diagram, but keep it within the model, use the main
menu |
Name
Text box. The name of the class. The name of a class has a leading capital letter, with words separated by “bumpy caps”.
![]() | Note |
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The ArgoUML critics will complain about class names that do not have an initial capital. |
Stereotype
Drop down selector.
Class is provided by default with the UML standard stereotypes for
Class
(implementationClass
and
type
) and for Classifier
(metaclass
, powerType
,
process
, thread
and
utility
).
![]() | Tip |
---|---|
One stereotype that is not part of the UML standard,
but is widely used is |
Navigate Stereotype
icon. If a
stereotype has been selected, this will navigate to the
stereotype property panel (see Section 17.4, “Stereotype”).
Namespace
Drop down selector. Records and allows setting of the namespace for the class. This is the package hierarchy.
Button 1 click on the entry will move the class to the selected namespace.
Modifiers
Check box, with entries
Abstract
,
Leaf
,
Root
, and
Active
.
Abstract
is used to declare
that this class cannot be instantiated, but must always be
subclassed. The name of an abstract class is displayed in
italics on the diagram.
![]() | Caution |
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If a class has any abstract operations, then it should be declared abstract. ArgoUML will not enforce this. |
Leaf
indicates that this
class cannot be further subclassed, while
Root
indicates it can have no
superclass. It is possible for a class to be both Abstract
and Leaf, since its static operations may still be
referenced.
Active
indicates that this
class exhibits dynamic behavior (and is thus associated with
a state or activity diagram).
Visibility
Radio box, with three entries
public
, protected
and
private
. Indicates whether the class is visible
outside the namespace.
Client Dependencies
Text area. Lists the “depending” ends of the relationship, i.e. the end that makes use of the other end.
Button 1 double click navigates to the dependency and opens its property tab.
Supplier Dependencies
Text area. Lists the “supplying” ends of the relationship, i.e. the end supplying what is needed by the other end.
Button 1 double click navigates to the dependency and opens its property tab.
Generalizations
Text area. Lists any class that generalizes this class.
Button 1 double click navigates to the generalization and opens its property tab.
Specializations
Text box. Lists any specialized class (i.e. for which this class is a generalization.
button 1 double click navigates to the generalization and opens its property tab.
Attributes
Text area. Lists all the attributes (see Section 17.6, “Attribute”) defined for this class. Button 1 double click navigates to the selected attribute.
Association Ends
Text box. Lists any association ends (see Section 17.11, “Association”) of associations connected to this class.
Button 1 double click navigates to the selected entry.
Operations
Text area. Lists all the operations (see Section 17.7, “Operation”) defined on this class. Button 1 click navigates to the selected operation.
Owned Elements
Text area. A listing of artifacts contained within the classes' namespace. This is where any inner class (see Section 17.5.2, “Class Property Toolbar”) will appear
Button 1 double click on any of the artifacts navigates to that artifact.
![]() | Tip |
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Most namespace hierarchies should be managed through the package mechanism. Namespace hierarchies through classes are best restricted to inner classes. Conceivable datatypes, signals and interfaces could also appear here, but actors and use cases would seem of no value. |