Software Design Architecture UML Activity Diagrams UML Activity

Software Design & Architecture UML Activity Diagrams

UML Activity Diagram • A UML activity diagram shows sequential and parallel activities in a process. They are useful for modeling business processes, workflows, data flows, and complex algorithms. • It shows a business process or a software process as a flow of work through a series of actions. People, software components, or computers can perform these actions.

UML Activity Diagram • Activity diagram is basically a flow chart to represent the flow form one activity to another activity. The activity can be described as an operation of the system. • Other diagrams are used to show the message flow from one object to another but activity diagram is used to show message flow from one activity to another. • Activity is a particular operation of the system http: //www. tutorialspoint. com/uml_activity_diagram. htm

UML Activity Diagram • Basic UML activity diagram notation involves an action, partition, fork, join, and object node. In essence, this diagram shows a sequence of actions, some of which may be parallel. Most of the notation is self-explanatory; two subtle points: • once an action is finished, there is an automatic outgoing transition • the diagram can show both control flow and data flow

An activity will be expanded in another diagram

Signals • They are useful, for example, when you need to model events such as time triggering an action, or a cancellation request.

Guidelines • This technique proves most valuable for very complex processes, usually involving many parties. Use-case text suffices for simple processes. • If modeling a business process, take advantage of the "rake" notation and sub-activity diagrams. On the first overview "level 0" diagram, keep all the actions at a very high level of abstraction, so that the diagram is short. Expand the details in sub-diagrams at the "level 1" level, and perhaps even more at the "level 2" level, and so forth. • Related to the above, strive to make the level of abstraction of action nodes roughly equal within a diagram.

Activity Diagrams in the UP • One of the UP disciplines is Business Modeling; its purpose is to understand communicate "the structure and the dynamics of the organization in which a system is to be deployed". A key artifact of the Business Modeling discipline is the Business Object Model (a superset of the UP Domain Model), which essentially visualizes how a business works, using UML class, sequence, and activity diagrams. Thus, activity diagrams are especially applicable within the Business Modeling discipline of the UP.

Constructing Activity Diagrams • Collect information sources—How am I supposed to know that? • Find activities and actions—What has to be done when actors draw upon offered goods and services? • Adopt actors from business use cases—Who is responsible for each action? • Connect actions—In which order are actions processed? • Refine activities—Do any other activity diagrams have to be added? • Verify the view—Is everything correct? https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Constructing Activity Diagrams • In case study, you can find the following work steps for passenger services: • Passenger checks in (derived from use case diagram); this entails issuing a boarding pass though passenger services. • Passenger boards airplane (derived from use case diagram). https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Constructing Activity Diagrams • In addition to this, there are other steps and events: • Passenger arrives at check-in counter and shows his or her ticket; this event initiates the check-in activity. • Luggage is loaded into the airplane by baggage transportation. • At first, just as above, activities can be described in an informal manner. We often find pre-existing documentation of processes, either informal or structured, which can be used as a basis to find activities and actions. https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Constructing Activity Diagrams https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Constructing Activity Diagrams • When a passenger checks in, he or she first shows his or her ticket at the check-in counter. The ticket will be checked for its validity. If the ticket is not OK the passenger will be referred to customer service. If the ticket is OK the passenger will check his or her luggage. If the luggage has excess weight he or she will pay an additional fee. The luggage will be forwarded to baggage transportation. The passenger receives his or her boarding pass. https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Constructing Activity Diagrams https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Constructing Activity Diagrams https: //sourcemaking. com/uml/modeling-business-systems/external-view/constructing-activity-diagrams

Example • Develop an activity diagram based on the following narrative. The purpose of the Open Access Insurance System is to provide automotive insurance to car owners. Initially, prospective customers fill out an insurance application, which provides information about the customer and his or her vehicles. This information is sent to an agent, who sends it to various insurance companies to get quotes for insurance. When the responses return, the agent then determines the best policy for the type and level of coverage desired and gives the customer a copy of the insurance policy proposal and quote.

Example