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Activity and sequence diagram are the two system behavior diagrams. The activity diagram represent the activities flow in a system while sequence diagrams depicts flow of message sequence from one object to another object in the system. Workflow model in a system is been created with the help of activity diagram while the power to visualize the sequence of calls in a system can be done with help of sequence diagram.
The activity and sequence diagrams both are UML diagrams and are used to represent the control flow in the system.
Activity Diagram:
• It represents the UML, which is used for modelling the workflow of the system.
• It is used for functional modelling which shows the message flow within the different activity of a predefined system.
• It describes the operational flow of the system with the help of pictorial representation which can be either sequential, branch, etc.
• It represents process execution by describing the sequence of several objects as well as use case of the predefined system.
There are various different elements that are used in the pictorial representation of activity diagram which are mentioned below:
1. Initial node: Indicates the beginning of workflow.
2. Control Flow: Shows direction of workflow.
3. Stop Node: End of the workflow.
4. Activity: Indicates step in process.
5. Decision box: Indicating a choice or decision making.
6. Guard Condition: Condition attached to control flow.
7. Event: Trigger attached to flow.
8. Connector: It has multiple inputs and multiple outputs.
9. Continuation Node: Help to give continuity from 1 page through another page.
10. Branch and Merge.
11. Fork and Join: Has ability to show multiple activity parallel activity.
12. Nested Loop Activity: It consists a series of activities internally
Sequential Diagram:
• It represents the UML, which is used for visualizing3872453a8d444e3c85013bd9dc138545 sequence of the flow in the system that is predefined to do certain special functions in the system.
• It is used for dynamic modelling which shows the message flow within the different object of a predefined system.
• It describes the interaction between different objects in a system with the help of pictorial representation which can be step by step process.
• It represents process time order by describing the sequence of several objects in a single use case of the predefined system.
The sequence diagram can be formed by the classes that are discovered by Boundary, Entity and Controller Class. It includes Lifeline, Camel Casting, Return message and focus of control. It always flows in timeline.
