Permission Relationships
A permission relationship is a type of dependency relationship that gives one model element access to the contents of another model element. The model element that gains permission is the consumer in the relationship, and the model element that grants permission is the supplier. Permission relationships include access, friend, and import relationships.
For example, a model may be separated into layers to group classes or subsystems that are at the same levels of abstraction. The architect places each layer in a package, so the model elements specific to the application (for example, the classes that implement the user interface) are in one package, and the model elements specific to the type of business (for example, a subsystem that is used to process credit card transactions) are in another package. An access relationship pointing from the application package to the business package indicates that one or more model elements in the application package can access the model elements in the business package.
Connector
A permission relationship appears as a dashed line with an open arrow. It points from the consumer model element to the supplier model element. A stereotype appears next to the connector to indicate the type of permission.
Types of Permission Relationships
The type of access that the consumer model element has to the contents of the supplier model element is defined by a stereotype. The following table identifies the predefined types of permission relationships.
|
Name |
Keyword |
Description |
|
Access |
«access» |
Indicates that the consumer model element can access the public contents of the supplier model element. This type of permission relationship typically connects packages. |
|
Friend |
«friend» |
Indicates that the consumer model element has access to the contents of the supplier model element regardless of the content's visibility. This type of permission relationship typically connects either operations or classes to other classes. |
|
Import |
«import» |
Indicates that the consumer model element adds the public contents of the supplier model element to its namespace. This type of permission relationship typically connects packages. |
Related Topics
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