94 lines
3.7 KiB
Plaintext
94 lines
3.7 KiB
Plaintext
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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****************************************************************************/
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/*!
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\example statemachine/pingpong
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\title Ping Pong States Example
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\brief The Ping Pong States example shows how to use parallel states together
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with custom events and transitions in \l{The State Machine Framework}.
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This example implements a statechart where two states communicate by
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posting events to the state machine. The state chart looks as follows:
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\image pingpong-example.png
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\omit
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\caption This is a caption
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\endomit
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The \c pinger and \c ponger states are parallel states, i.e. they are
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entered simultaneously and will take transitions independently of
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eachother.
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The \c pinger state will post the first \c ping event upon entry; the \c
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ponger state will respond by posting a \c pong event; this will cause the
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\c pinger state to post a new \c ping event; and so on.
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\snippet statemachine/pingpong/main.cpp 0
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Two custom events are defined, \c PingEvent and \c PongEvent.
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\snippet statemachine/pingpong/main.cpp 1
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The \c Pinger class defines a state that posts a \c PingEvent to the state
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machine when the state is entered.
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\snippet statemachine/pingpong/main.cpp 2
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The \c PingTransition class defines a transition that is triggered by
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events of type \c PingEvent, and that posts a \c PongEvent (with a delay
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of 500 milliseconds) to the state machine when the transition is
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triggered.
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\snippet statemachine/pingpong/main.cpp 3
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The \c PongTransition class defines a transition that is triggered by
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events of type \c PongEvent, and that posts a \c PingEvent (with a delay
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of 500 milliseconds) to the state machine when the transition is
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triggered.
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\snippet statemachine/pingpong/main.cpp 4
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The main() function begins by creating a state machine and a parallel
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state group.
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\snippet statemachine/pingpong/main.cpp 5
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Next, the \c pinger and \c ponger states are created, with the parallel
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state group as their parent state. Note that the transitions are \e
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targetless. When such a transition is triggered, the source state won't be
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exited and re-entered; only the transition's onTransition() function will
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be called, and the state machine's configuration will remain the same,
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which is precisely what we want in this case.
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\snippet statemachine/pingpong/main.cpp 6
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Finally, the group is added to the state machine, the machine is started,
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and the application event loop is entered.
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*/
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