một khi bạn bắt đầu sử dụng một. Vì vậy, có một hơi thở sâu, và cuộc hành trình chúng ta hãy để M3. Bạn có một fan hâm mộ khoa học viễn tưởng? Một tín đồ của Star Trek, có lẽ? Bạn đã bao giờ UML đã biến kính lúp trên sơ đồ hoạt động và thêm vào một số kỹ thuật mô hình. | 334 Hour 19 Preconditions A totaled check Postconditions A printed check Steps 1. The server clicks a button on the handheld to print the check. 2. The networked printer in the serving area prints the check. 3. The server clicks a button on the handheld to remove this order from the list of active orders. Benefiting Actor Customer Summon an Assistant This one is important because assistants help keep everything flowing smoothly. Description Request an assistant to clean the table for the next customer. Assumptions The system allows wireless communication between two mobile employees. The system has a user interface screen for sending a message to an assistant. Preconditions An empty table that must be cleaned and reset Postconditions The assistant has come to the table to clean and reset it. Developing the Use Cases 335 Steps 1. The server activates the interface for sending a message to an assistant. 2. The server receives an acknowledgment from the assistant. As in the Notify chef about party status use case the last step uses the Receive acknowledgment use case. Benefiting Actor Assistant Analyzing this use case as well as the use cases in the Assistant package might lead you to believe that splitting the Assistant class into two classes Assistantserver and Assistantchef is a good idea. It just makes things cleaner. Could they be children of an abstract Assistant class They could but you probably wouldn t gain much from setting up this abstract class. Creating these two new classes necessitates revisiting the domain analysis. You have to rework the class diagrams particularly the diagram for Employee as Figure shows. FIGURE The updated class diagram for Employee. You would also have to update your package diagrams to include an Assistant Server package and an Assistant Chef package. This is an example of how the segments of GRAPPLE feed each other. The knowledge gained during use case analysis has helped you evolve the domain analysis. 336 Hour 19 .
