Activity diagram of UML

Activity Chart:

concept: an activity diagram is a flowchart used to describe the activities in the process and their transitions.

element: contains elements of activity, State, transition, decision, and so on

1. Activity (Action):

An activity in an activity diagram that represents the action of a work or a step that represents a workflow, represented by a rounded rectangle.

In determining the name of the activity should be properly named, as far as possible accurate word description.

2. Status (State):

The main consists of two special States, the start and end states, the start State is represented by a solid black dot, and the ending state is represented by a solid black dot with a circle.

Note: Each activity graph can have only one start state but can have countless end states (unlike a state diagram).

3. Transfer:

Used to represent the flow of control between activities, States, or between activities and states. Represented by a solid line with an open arrow.

4. Decision-Making:

is based on the judging conditions to select the direction of control flow continuation, with a diamond representation.

Other elements:

1. Swimlane (Swinlane):

is the zoning in the activity diagram, where each swimlane represents a responsible area. A swimlane includes a set of related activities.

Swimlane makes the activity diagram very neat, as they greatly enhance the readability of the activity diagram.

2. Bifurcation and coupling:

Forks are used to represent the branching of parallel activities, which are used to aggregate parallel activities into synchronous processing.

3. Object Flow:

An activity can input and output objects, and can modify the state of an object to reflect the dependencies between the activity and the object.

differ from other diagrams:

differs from the state diagram :

activity diagrams focus more on the flow of control from one activity to another, which is an internal process driven process, whereas a state diagram focuses on a process from one state to another, with the involvement of external events.

Different from Flowchart:

1) flowchart focuses on the process of processing, its main control structure is the order, branches and loops, each processing process has a strict sequence and time relationship. The activity diagram describes the rules followed by the sequence of object activity, which focuses on the behavior of the system rather than the process of the system.
2) The activity diagram can represent the situation of concurrent activities, and the flowchart is not.
3) The activity diagram is object-oriented, and the flowchart is process oriented.

activity diagram main application:

1. Describe the behavior of a use case

The activity diagram is especially useful for use case descriptions, which can model the workflow of a use case, showing the path between the use case and the use case, and he can also explain to the reader what conditions the use case will take effect and what conditions or states the system retains after the use case has been completed.

2. Understanding the Workflow

Activity diagrams are useful for understanding business processes. You can draw an activity diagram that describes the business workflow, and how the business process operation is going to change.

3. Algorithms that describe complex processes

In this case the activity diagram used is like a program flowchart, the general sequence, branching process in the activity diagram can be fully performed.

computer room Charge Example (no lane map, understanding is still shallow hope that we have a lot of advice)