UML 2.0 Class Diagram Elements

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Model element is any component of your model that you can put on a diagram. Model elements include nodes and links between them.

Available Model Elements of UML 2.0 Class Diagrams

You can create model elements using the context menus in the Model and Diagram Views and using the Tool Palette.

The following table lists the available model elements of UML 2.0 class diagrams:

UML 2.0 class diagram elements

Icon	Element	Name	Type	Comment
		Package	Node
		Class	Node
	- New UML 2.0	Interface	Node	You can switch between these graphical representations using the View as Class property in the Object Inspector.
		Association Class	Node	An association class has both association and class properties and can be seen as an n-ary association that also has class properties. See N-ary Association in Relationships Among Elements of Class Diagrams.
		Enumeration	Node
		Data Type	Node
		Port		A port is a property of a classifier (class or association class) that specifies a distinct interaction point between that classifier instance and its environment or between a classifier instance and instances it may contain.
		Instance Specification	Node	An instance specification specifies the existence of an entity that represents an instance of a model element in a modeled system and completely or partially describes the entity.
		Generalization Implementation	Link Link	Generalization and Implementation links are created by the same command. Generalization indicates inheritance between two classes or two interfaces. Implementation indicates a class that implements an inherited interface. See the description of Generalization and implementation relationships in Relationships Among Elements of Class Diagrams.
		Provided Interface	Link	The set of interfaces realized by a classifier are its provided interfaces, which represent the obligations that instances of that classifier have to their clients. The provided interfaces describe the services that the instances of that classifier offer to their clients.
		Required Interface	Link	Required interfaces specify services that a classifier needs in order to perform its function and fulfill its own obligations to its clients.
		Association	Link	Possible types: association, aggregation, and composition. See the description of Association relationships in Relationships Among Elements of Class Diagrams.
		Association End	Opens the Association End context menu to select the type (class, structure, enumeration, union) of a participant to add as an association end.	Used to specify association end classes (participants) in an association, which property is represented by an Association Class. See N-ary Association in Relationships Among Elements of Class Diagrams.
		Dependency	Link	See the description of Dependency relationships in Relationships Among Elements of Class Diagrams.
		Node by Pattern	Node	Opens Pattern Wizard.
		Link by Pattern	Link	Opens Pattern Wizard.
		Constraint	"OCL expression" or "free-syntax constraint"	By default, the Modeling tries to validate the specified constraint text as an OCL expression. If it cannot be validated, then the Constraint is red highlighted. To suppress red highlighting, set the Constraint language property to Text (in the Object Inspector).
		Constraint link	Constraint link
		Note	Annotation
		Note Link	Annotation link	You see the note connected by the note link with another modeling element.
		Image	Illustration - frame of the image placeholder.	The Tool Palette command puts on a diagram only the empty frame of the image placeholder. To render an image in this frame: Select this image placeholder. In the Image path property of the Object Inspector, specify the file of the image to be rendered. Here you see the Embarcadero image, rendered in the frame of the image placeholder.
		Image Link	Illustration link	You see the Embarcadero image connected by the image link with another modeling element.

Container Elements. Members of Container Elements

On class diagrams, some types of elements (containers) can have internal members. Internal members can be created in container elements using the context menus of container elements in the Model View and in the Diagram View.

The table below lists the available container elements of UML 2.0 class diagrams along with the members that can be added into them.

Available container elements and members

Container element	Members available
Package	Package Class Association Class Interface Enumeration Data Type Instance specification
Class	Class Interface Attribute Operation Constructor Enumeration Data Type Interaction
Association Class	Class Interface Attribute Operation Constructor Enumeration Data Type Interaction
Interface	Attribute Operation Enumeration Data Type Interaction
Data Type	Attribute Operation
Enumeration	Enumeration literal

Classifiers. Inner classifiers

In general, those modeling elements that can have instances are called classifiers. Classifiers have structural features (attributes) and behavioral features (operations). In the Modeling, classifiers are the basic nodes of Class diagrams: classes, interfaces, and association classes. Some of them can include other classifiers, or inner classifiers.

The table below lists the container elements of class diagrams along with the inner classifiers that you can add into container elements.

Inner classifiers:

Container element	Available inner classifiers
Class	Class Interface
Association Class	Class Interface
Interface

See Also

• UML 1.5 Class Diagrams
• Class Diagram Procedures