防护条件不同的状态转换 [英] state transition with different guard condition

问题描述

在状态模式下如何建模?

In the state pattern how is this modeled ?

状态A到触发器X和状态C1上的状态B，当前状态为A

state A to state B on trigger X and conditon C1 when current state is A

当当前状态为A时，状态X会在触发器X和状态C2上变为状态C

state A to state C on trigger X and condition C2 when current state is A

通常如何完成?我有很多可能需要实施的警卫条件.

how is this usually accomplished ? I have a lot of guard conditions that I may need to implement.

推荐答案

这很标准，例如参见此示例.

[不是根据功课编辑的！]

假设我理解正确:

• 您有一个事件(X)，可以触发两个可能的过渡之一
• 根据适合的条件(C1或C2)选择向哪个火场过渡

• You have one event (X) which can trigger one of two possible transitions
• Selecting which transition to fire is made according to which condition holds true (C1 or C2)

如果是这样，这是使用保护条件的标准情况.语法为:

If so that's a standard case for using guard conditions. The syntax would be:

• X[C1]作为过渡A-> B上的标签，并且
• X[C2]在A-> C过渡上.

• X[C1] as the label on the transition A->B, and
• X[C2] on the transition A->C.

C1& C2必须计算为布尔值，因此可以根据您的注释替换var==2.即标签将变为X[var==2]和X[var==3].

C1 & C2 must evaluate to booleans, so it would be fine to substitute var==2 as per your comment. i.e. the labels would become X[var==2] and X[var==3].

为了使其在语义上正确，C1& C2在状态A中必须互斥-否则您将无法确定.

For it to be semantically correct, C1 & C2 must be mutually exclusive in state A - otherwise you have non-determinism.

hth.

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