Secondary actors in Use Case Diagrams, unlike primary actors, are not directly involved in the primary goal of the system but provide support services or resources that the system needs to accomplish its tasks. They are entities that interact with the system but are not the primary users or external systems that the system is designed for.
For Example:
Let’s understand secondary actors with the help of an e-commerce system.
- This secondary actor represents an external service that the e-commerce system interacts with to handle the shipping of products.
- The shipping service is not directly involved in the primary goal of the e-commerce system (facilitating online transactions), but it provides a critical service that the system relies on to fulfill orders.
Roles of Secondary Actors
Secondary actors play important roles in a system, even though they are not directly involved in its primary functionality. Here are some key aspects of their importance and roles:
1. Supporting Functionality
Secondary actors provide supporting services or resources that are crucial for the system to achieve its primary goals. These services may include logging, authentication, notification, or integration with external systems.
2. Boundary Definition
Including secondary actors helps define the boundaries of the system and clarifies its interactions with external entities. This is important for understanding the system’s scope and ensuring that all necessary interactions are considered during design and development.
3. Indirect Interactions
While secondary actors do not directly participate in the primary use cases of the system, they may trigger or be triggered by the system’s actions. Understanding these interactions is important for designing robust and reliable systems.
4. System Integration
Secondary actors often represent external systems or services that the system needs to integrate with. Identifying these actors helps in planning and implementing the necessary integration points and interfaces.
5. Impact Analysis
Changes to secondary actors or their interfaces can have an impact on the system. By understanding the interactions with secondary actors, developers can analyze the potential impact of changes and plan accordingly.
In conclusion, secondary actors play a crucial role in supporting the functionality of a system, defining its boundaries, clarifying interactions, enabling system integration, and analyzing the impact of changes. Understanding and identifying secondary actors is important for designing systems that are robust, reliable, and able to meet the needs of their users.