Скачать или смотреть How to Identify Actors and Systems for Your Use Case Diagram

Struggling with use case diagrams? Learn how to effectively identify `actors` and `systems` in your projects, particularly when integrating new sensors with existing systems.
---
This video is based on the question https://stackoverflow.com/q/65147382/ asked by the user 'Whippet' ( https://stackoverflow.com/u/14764559/ ) and on the answer https://stackoverflow.com/a/65149228/ provided by the user 'bruno' ( https://stackoverflow.com/u/2458991/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Identifying the correct system and actors for use case diagram

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Identify Actors and Systems for Your Use Case Diagram

Creating a use case diagram can be a challenging task, especially when determining the roles of different components within your system. If you’re finding it difficult to correctly identify the actor and system, you’re not alone. In this guide, we will explore the concepts of actors and systems in use case diagrams, particularly focusing on scenarios involving new sensors that interact with existing systems.

Understanding the Basics

Before we dive deeper, let’s clarify what actors and systems are in the context of use case diagrams:

Actor: An actor represents a user or another system that interacts with the system being modeled. Actors are always external to the system.

System: A system encompasses everything being modeled, including all functionalities and processes to be carried out.

The Dilemma: Sensors as Actors or Systems?

The main question arises when you have multiple sensors that interact with an existing system. Here’s the dilemma:

You are developing four sensors intended to interact with an already established system.

You originally contemplated treating the sensors as secondary actors. However, this raised concerns about their classification since they are not typically viewed as external components.

Considering the Sensors as Systems

One possible solution is to approach the situation by envisioning the sensors as a system itself. Here’s how you can perceive it:

If you treat the sensors as the primary system:

The existing system can be viewed as an actor, even potentially as a primary actor if it activates your use cases.

In this view, you document how your sensors function and how they interact with the external existing system.

Reversed Roles:

Conversely, if you decide to describe the existing sensors along with their functionalities, your sensors would become the actors while the existing system would be the new primary system you’re documenting.

Understanding System and Subsystem Dynamics

In complex projects, it’s essential to remember:

When considering the overall system, if it encompasses both your sensors and the existing system, both can be regarded as subsystems.

Your approach should focus on how they interact within the overall architecture.

Representation in Your Diagrams

Here’s a quick guide for documenting your use case diagrams:

Identify the Primary System: Choose which of your sensors or existing systems will serve as the primary focus.

Define the Actors: Based on which system you selected, identify what constitutes the actors. Who or what interacts with the primary system?

Diagram Relationships:

Use arrows to show interactions.

Clearly label each component to avoid confusion.

Conclusion

In summary, identifying whether your sensors or the existing system should be treated as actors or systems largely depends on the perspective you choose to adopt. It’s a matter of how you define the system’s boundaries. Always document the reasoning behind your decisions, as this clarity will help you in your school project—and it’s essential for sharing your insights with peers and stakeholders.

As you approach your use case diagrams, remember that there is flexibility in representation, and ensure that your diagrams are easily interpretable based on the focus chosen. Good luck with your project!