51 lines
1.2 KiB
Go
51 lines
1.2 KiB
Go
// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.
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package machine
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import (
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_ "errors"
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"fmt"
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)
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type Transitioner interface {
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Run(m Modeler) error
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Subscribe(s Subscriber)
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}
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type Transition struct {
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trigger string
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source State
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dest State
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subscriptions []Subscriber
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}
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func NewTransition(trigger string, source State, dest State) Transitioner {
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return &Transition{trigger: trigger, source: source, dest: dest}
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}
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func (r *Transition) Run(m Modeler) error {
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currentState := m.InspectState()
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if currentState == r.dest {
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return nil
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}
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if currentState == r.source || r.source == "*" {
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res := m.ChangeState(r.dest)
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if res == currentState {
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r.Notify(EXITSTATEEVENT, currentState, r.dest)
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r.Notify(ENTERSTATEEVENT, currentState, r.dest)
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return nil
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}
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}
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return fmt.Errorf("Transition from %s to %s failed on model state %s", r.source, r.dest, currentState)
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}
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func (r *Transition) Subscribe(s Subscriber) {
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r.subscriptions = append(r.subscriptions, s)
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}
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func (r *Transition) Notify(on Eventtype, source State, dest State) {
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for _, s := range r.subscriptions {
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s.Notify(&EventMessage{On: on, Source: source, Dest: dest})
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}
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}
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