Use case diagram dependency relationship

UML relationships in use-case diagrams

use case diagram dependency relationship

An include dependency, formerly known as a uses relationship in UML v and earlier, is a. A model may have many use cases, so how do we organize the use cases that define what a system should do? And how do we use this information about use. When it comes to drawing use case diagrams one area many struggles with is showing various relationships in use case diagrams. In fact.

So dependency could in fact have some grave runtime semantics implications. A dependency is generally shown as a dashed arrow pointing from the client dependent at the tail to the supplier provider at the arrowhead. The arrow may be labeled with an optional stereotype and an optional name.

Use Case Diagram - UML 2 Diagrams - UML Modeling Tool

Class SearchController depends on requires SiteSearch interface. For many years UML specifications provide contradictory example of the dependency shown below.

3.04_The ''include'' Dependency

The explanation for the Figure 7. In this case, the dependency is an instantiate dependency, where the Car class is an instance of the CarFactory class.

use case diagram dependency relationship

Car class has a dependency on the CarFactory class. CarFactory class depends on the Car class.

use case diagram dependency relationship

This example in fact shows opposite to what UML specification states. CarFactory depends on the Car class. Car class could be defined without the knowledge of CarFactory class, but CarFactory requires Car for its definition because it produces Cars. It is also wrong to say that " It is possible to have a set of elements for the client or supplier. In this case, one or more arrows with their tails on the clients are connected to the tails of one or more arrows with their heads on the suppliers.

And how do we use this information about use cases to determine how best to execute a project while considering how use cases are related to one another, including what some use cases might have in common, and also taking into account use cases that are options of other use cases? Specialized types of dependencies, called include and extend dependencies, address these questions; dependencies are discussed in Chapter 3.

Use case diagram

The next few sections discuss these specialized types of dependencies. Figure elaborates on the use cases in Figure to show that the activities of the project manager, resource managers, and system administrators are logged when they are performing the use cases shown in the diagram.

use case diagram dependency relationship

Thus, logging activities are common to these three use cases. We can use an include dependency to address this type of situation by factoring out and reusing common behavior from multiple use cases. Use cases with common behavior An include dependency from one use case called the base use case to another use case called the inclusion use case indicates that the base use case will include or call the inclusion use case.

UML Use Case Extend

A use case may include multiple use cases, and it may be included in multiple use cases. An include dependency is shown as a dashed arrow from the base use case to the inclusion use case marked with the include keyword. The base use case is responsible for identifying where in its behavior sequence or at which step to include the inclusion use case. This identification is not done in the UML diagram, but rather in the textual description of the base use case.

Figure refines Figure using include dependencies. The Log Activity use case is common to the Manage Project, Manage Resource, and Administer System use cases, so it is factored out and included by these use cases.

Include dependencies You can use an include dependency when a use case may be common to multiple other use cases and is therefore factored out of the different use cases so that it may be reused. Consequently, you must analyze and develop that use case before you develop the three use cases that depend on it. Figure elaborates the Manage Project use case in Figureand shows that a project manager may manage projects by maintaining the project itself, its activities, or its tasks.

Thus, maintaining the project, its activities, and its tasks are options of managing a project. You can use an extend dependency to address this situation by factoring out optional behavior from a use case.

uml - What is the difference between 'includes', 'extends' and 'uses'? - Stack Overflow

Use cases with optional behavior An extend dependency from one use case called the extension use case to another use case called the base use case indicates that the extension use case will extend or be inserted into and augment the base use case.

A use case may extend multiple use cases, and a use case may be extended by multiple use cases. An extend dependency is shown as a dashed arrow from the extension use case to the base use case marked with the extend keyword.

use case diagram dependency relationship

The base use case is responsible for identifying at which steps in its behavior sequence the extending use cases may be inserted. Figure refines Figure using extend dependencies.

use case diagram dependency relationship

Simple extend dependencies The location in a base use case at which another behavior sequence may be inserted is called an extension point. Extension points for a use case may be listed in a compartment labeled "Extension Points" where each extension point is shown inside the compartment with an extension-point name followed by a colon followed by a suitable description of the location of the extension point in the use case's behavior sequence.

Locations may be described as being before, after, or in-the-place-of a step in the base use case's behavior sequence. For example, the Manage Project use case may have a behavior sequence for finding a project on which to work followed by an extension point named Project Selected followed by another behavior.