P04 Exclusive Choice 排他选择

Pattern 4: Exclusive Choice 排他选择 The divergence of a branch into two or more branches such that when the incoming branch is enabled, the thread of control is immediately passed to precisely one of the outgoing branches based on a mechanism that can select one of the outgoing branches. 流程中的一个点，基于决定或者工作流中的数据，流向若干个分支中的一个。