在所有流都到达合并节点之前,UML 合并节点不会退出吗?

Does UML merge node doesn't exit until all flows have arrived at the merge node?

我是 UML 的初学者并尝试理解它。现在我读 UML Demystified。有这样一句话:

A merge node doesn't exit until all flows have arrived at the merge node.

但是www.omg.org/spec/UML/2.5/Beta2中有一个标题为Figure 15.12 Activity node example (where the arrowed lines are the only non-activity node symbols)的图:

现在我认为如果上面的句子是正确的,上图说 Activity 将被 merge 节点阻止;因为到达所有流是不可能的;因为只能拒绝或接受订单。

现在我想知道是引用的句子不正确还是我误解了什么?

来自 UML 2.5 规范:

15.7.21 MergeNode [Class]

A merge node is a control node that brings together multiple alternate flows. It is not used to synchronize concurrent flows but to accept one among several alternate flows.

因此它随时接受单个令牌并将其传递到其传出流。一般来说,书作者写的是他们的解释——这可能是错误的。在任何情况下,您都需要遵守 UML 规范的规定。