Để giải thích một sự hợp tác đòi hỏi phải có một số sơ đồ cho thấy cả hai bối cảnh và sự tương tác giữa các yếu tố hợp tác. Tham gia phối hợp một số yếu tố có thể được sử dụng trong nhiều cách. Sơ đồ tiêu biểu sử dụng bao gồm tổng quan về truyền thông, trình tự, tương tác, hoạt động, và máy nhà nước, bao gồm trong chương sau. | 80 Chapter 3 To explain a collaboration requires a number of diagrams showing both the context and the interaction between the collaboration elements. Participating in a collaboration are a number of elements that can be used in many ways. Typical diagrams used include communication sequence interaction overview activity and state machines as covered in later chapters. The type of diagram to use to give a complete picture of the collaboration depends on the actual case. In some cases one diagram may be sufficient in other cases a combination of different diagrams may be necessary. A scenario is an instance of a use case. The scenario is a specific execution path a specific flow of events that represents a specific instantiation of the use case one usage of the system . When a scenario is viewed as a use case only the external behavior toward the actors is described. When viewed as a collaboration occurrence the scenario includes the interaction between the parts inside the system or the runtime architecture as shown in a composite structure diagram. For more on collaborations composite structures and runtime architecture see Chapter 7. A use case can own diagrams that detail its internal structure. A use case can own diagrams to describe the actions that take place to deliver the benefits of the use case. These can emphasize the runtime architecture or other elements that emerge with the implementation of the use case. For example Figure shows a use case that owns a state machine. Such devices make use cases more flexible and link them to other diagrams that can more precisely map actions. Realizing a use case requires the designer to transform the different steps and actions in the use-case description as described in text or other diagrams to classes operations in these classes and relationships between them. This is described as allocating the responsibility of each step in the use case to the classes participating in the collaboration that realizes the use
