我正在使用新的Boost 1.44.0 MSM库来生成状态机。在这个状态机中有两类事件class1
和class2
。 class1
事件可以由状态S1
或S2
进行处理,而class2
事件只能由状态S2
进行处理。提升MSM只处理内部转换
一个特殊的class1
事件upgrade_req
请求从状态S1
升级到状态S2
。
,我实现了在升压:: MSM如下:
// State S1 and S2 allow any class1 events
struct class1 {};
// Only state S2 allows class2 events
struct class2 {};
// an upgrade request is a class1 event that requests an upgrade to state 2
struct upgrade_req : public class1 {};
struct MyFSM : public msm::front::state_machine_def<MyFSM>
{
/// State 1. Allows any class1 event
struct S1 : public msm::front::state<>
{
/// functor says "processing event in State 1"
struct ProcessEvent { /* ... */ };
struct internal_transition_table : mpl::vector<
// Event Action Guard
// +-------+-------------+------------+
Internal< class1, ProcessEvent, none >
> {};
}; // S1
/// State 2. Allows any class1 or class2 events
struct S2 : public msm::front::state<>
{
/// functor says "processing event in State 2"
struct ProcessEvent { /* ... */ };
struct internal_transition_table : mpl::vector<
// Event Action Guard
// +-------+-------------+------------+
Internal< class1, ProcessEvent, none >,
Internal< class2, ProcessEvent, none >
> {};
}; // S2
/// everybody starts in state 1
typedef S1 initial_state;
/// send an error if a class2 event was received for state1
struct SendError { /* ... */ };
/// Send a response to the upgrade request
struct SendUpgradeRsp { /* ... */ };
/// functor returns true if the request to upgrade to state 2 is OK.
struct VerifyUpgradeReq { /* ... */ };
struct transition_table : mpl::vector<
// Start Event Next Action Guard
// +------+-------------+------+----------------+------------------+
Row< S1, class1, none, none, none,
Row< S1, class2, S1, SendError, none >,
Row< S1, upgrade_req, S2, SendUpgradRsp, VerifyUpgradeReq >,
Row< S2, class1, none, none, none,
Row< S2, class2, none, none, none >
> {};
}; // MyFSM
我的问题是,当我用这个,因为它是永远不会被主MyFSM::transition_table
处理upgrade_req
事件。它只能由S1::internal_transition_table
处理。
例如:
int main(int argc, char* argv[])
{
msm::back::state_machine<MyFSM> sm;
sm.start();
sm.process_event(class1());
sm.process_event(upgrade_req());
sm.process_event(class2());
return 0;
}
我就是愿意这样做的输出是:在国家
处理事件1.
升级请求确定。在国家2.
但是,
处理事件我所得到的是这样的:在国家1
处理事件
处理事件的国家1.
错误。收到状态1中的第2类事件。
有没有人有关于如何解决此问题的建议?
感谢, PaulH