EA & UML Sun Arch - State Diagram :: Redraw Button State Diagram

State diagram of the button handling module,It has been explained in the previous article,But when we model the signal system engine,It was found that the original design did not meet the needs,Therefore, the completed model needs to be modified.

Such modifications frequently occur during software development,What needs to be done is not to suppress this modification,Rather, let this modification happen as early as possible.This is also a role of modeling.

在前面的例子中,It is hoped that the stop button and the pedestrian through the request button can be expressed in a sequence diagram,As a result, neither situation is appropriate.This paper adopts another strategy：

1. Design a state diagram for standard button handling,The stop button can use this state diagram
2. Pedestrians extend the standard button module by requesting the button module

Standard button module state machine

Work状态

装置工作状态,This state contains two sub-states, valid and invalid.WorkStatus if acceptedShutdown要求,The transition to the completed state.从UMLState machine semantics,regardless of the statusWorkingthe substate of ,The above migrations all work.

Disable状态

The device does not accept user button actions.接受到DeviceEnable事件之后,向Enable状态迁移.

Enable状态

接受DeviceDisable事件以后,向Disable状态迁移;When a button press event is received,向Disable状态迁移,But at the same time send the button press event.

If compared with the previous button device state diagram,It should be seen that this scheme is clearer,The focus is also more prominent.

Pedestrian through the request button state machine

First, compare it with the standard button module state diagram,The difference can be seenEnableThe status is further refined,At the same time, the corresponding migration has also changed.Only the added part is described below.

LaterReportWait状态

In this state if the user presses the button,Button press events are not sent immediately,而是向CmdReady状态迁移.如果接收到SetInstantReport通知,则向InstantReportWait状态迁移.

InstantReportWait状态

When a button press event is received in this state,向Disable状态迁移,But at the same time send the button press event.

CmdReady状态

Entering this state means,The user pressed the request button.当接收到HandlerReady事件时,向Disable状态迁移,But at the same time send the button press event.

补充说明

Although the order in which the articles are issued is sequential,But actually the signal system engine module and the pedestrian pass request button module and the state diagram are designed at the same time,同时完成的.Of course it can be done one after the other.

Although the state diagram designed in the previous article describing the button module has been greatly modified,But object-oriented thinking is the same.

参考资料：

14.2 Behavior StateMachines (6)--Substate machine state

14.2 Behavior StateMachines (10) --记法

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