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What is the primary role of a Boundary Object?
🌐 It defines interfaces to and communicates with the external environment. %%% What does a Boundary Class typically represent in a UML class diagram?
🖥️ It represents the User Interface (UI) or external systems' interfaces, depicting interactions between the system and its actors. %%% In terms of External Interaction, how does a Boundary Class function?
🔄 It acts as a Proxy: handling input/output operations and facilitating communication between the internal system and external entities. %%% What is the specific responsibility of a Boundary Object regarding Hardware?
🔌 Device I/O: It receives input from and/or sends output to a hardware device. %%%
What are the three key characteristics of a Boundary Class?
- Interface Representation (UI/External interfaces).
- External Interaction (Proxy) (Mediating communication).
- Device I/O (Hardware communication). %%% What is the primary function of an Entity Object?
📦 It encapsulates information and represents data that needs to be stored and managed within the system. %%% What are the two types of Entity Objects based on data lifespan?
⏳
- Data abstraction objects: Used for transient data (temporary).
- Database objects: Used for persistent data (long-term). %%% In a UML class diagram, what do the attributes of an Entity Class represent?
📋 They represent the properties or characteristics of the entity, corresponding to specific data fields. %%%
How do Entity Classes typically interact with one another?
🔗 Through associations (relationships) that indicate how different entities are connected. %%% If persistent data is stored in a database, what is the role of the Entity Object?
🎁 It acts as a wrapper: mapping database columns to the object's attributes. %%% Why is a mutex usually required when using Entity Objects in a multi-threaded environment?
🔒 Because Entity Objects are almost always passive, meaning they do not manage their own concurrency/execution flow. %%% What is the primary purpose of a Control Object?
🕹️ It provides overall coordination for a collection of objects within the system. %%% How do Control Objects facilitate the fulfillment of a Use Case?
🎼 They contain methods that orchestrate the sequence of actions needed to execute the use case logic. %%%
How does a Control Object interact with Boundary and Entity classes?
🔄 It receives input from Boundary classes, processes it, and interacts with Entity classes to retrieve or update data. %%% What defines a State-dependent control object?
🚦 Its behavior depends on its current state, and it changes states based on inputs (events) from other objects. %%% What is a Coordinator control object?
🤝 An overall decision-making object that controls others but is not state-dependent (e.g., a system scheduler). %%% What is the function of a Timer control object?
⏱️ It controls other objects on a periodic basis, triggered by an external clock. %%% What are the three types of Control Objects?
- State-dependent (Behavior depends on state).
- Coordinator (Decision making, non-state-based).
- Timer (Periodic triggers). %%%
What is the primary role of Application Logic classes?
🧠 They encapsulate the core functionality, algorithms, and logic of an application, playing a central role in executing its operations. %%% How do Application Logic classes interact with Entities and Controls?
🔗 They interact with Entity classes to retrieve/update data and with Control classes to coordinate the flow of system activities. %%%
What does it mean for Application Logic to be independent of presentation details?
🏗️ It ensures separation of concerns; changes to the User Interface (UI) should not directly impact the core application logic. %%% Why are Application Logic classes used to partition logic away from data?
🔄 Because logic is expected to change more frequently than the underlying data structures. %%% What is the difference between how Simple and Complex Algorithms are encapsulated?
🧮
- Simple: Often encapsulated directly within Entity objects.
- Complex: Placed in a separate class that interacts with multiple objects (similar to a coordinator). %%% What is the purpose of a Service type Application Logic class?
🛠️ It provides a specific service to other objects, such as reading/writing data or forwarding messages across a network. %%% Which specific object type is the only one allowed to communicate with an Actor?
🎭 Boundary Objects. Actors cannot interact with Controllers or Entities directly. %%% What are the communication limits for a Boundary Object?
🔌 it can only talk to Actors and Controllers. (It cannot talk directly to Entities). %%% Who are Entity Objects permitted to communicate with?
📦 Only Controllers and other Entity Objects. %%% Which class acts as the "middleman" that can talk to Boundary, Entity, and other Control objects?
🕹️ The Control class. (Note: It still cannot talk directly to Actors). %%% Can an Entity Object initiate communication with a Boundary Object?
❌ No. Communication between data (Entity) and the interface (Boundary) must be mediated by a Controller. %%% Which object types are allowed to communicate with others of their own type?
👥 Entity objects and Control objects. %%% Why is a Controller forbidden from talking to an Actor?
🧱 To ensure independence from presentation details; the logic (Controller) should only interact with the interface representation (Boundary). %%% Which types of objects are assumed to be active (concurrent) by default?
🏃 All non-entity objects. Each has its own thread of control and can operate in parallel. %%% What does it mean for an Entity Object to be passive?
🧘 It does not have its own thread; instead, it is called by active objects to perform tasks. %%% How does communication differ between Active and Passive objects?
💬
- Active to Active: Asynchronous communication.
- Active to Passive: Synchronous communication (e.g., a standard method call). %%% What is the primary purpose of a Boundary Object in the context of the Hardware/Software boundary?
🔌 To abstract away the details of communicating with the "hardware" side of the interface. %%% Why are Entity Objects usually the only passive objects in this architecture?
💾 Because their primary role is to store and manage data for other active components rather than orchestrating system behavior or timing.