系统顺序图 ●顺序图显示参与者和系统之间的事件 创建系统顺序图是调査要建造什么系统的工作的 部分 在进行逻辑设计之前以黑箱调查系统的行为 系统行为是描述系统做什么,而不是怎么做 系统顺序图 ●用例 系统合约
系统顺序图 ⚫ 顺序图显示参与者和系统之间的事件 ⚫ 创建系统顺序图是调查要建造什么系统的工作的 一部分 ⚫ 在进行逻辑设计之前以黑箱调查系统的行为 ⚫ 系统行为是描述系统做什么，而不是怎么做 ⚫ 系统顺序图 ⚫ 用例 ⚫ 系统合约
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enterItem(itemID, quantity) : Cashier :System endSale makePayment(amount) a UML loop interaction frame, with a boolean guard expression external actor to system Process Sale Scenario system as black box the name could be "NextGenPOS" but "System" keeps it simple the ":" and underline imply an instance, and are explained in a later chapter on sequence diagram notation in the UML a message with parameters it is an abstraction representing the system event of entering the payment data by some mechanism description, total return value(s) associated with the previous message an abstraction that ignores presentation and medium the return line is optional if nothing is returned total with taxes change due, receipt makeNewSale loop [ more items ]