基于枚举的FSM(有限状态机)

StateMachine.java

package com.yonyou.dmscloud.passengerflow.domain.model;


public class StateMachine {
    ReceptionRecord context;
    State state;

    StateMachine(ReceptionRecord context) {
        this.context = context;
        this.state = State.Initial;
    }

    public enum Event {Submit, Overtime}

    void submit() {
        state.process(this, Event.Submit);
    }

    void overtime() {
        state.process(this, Event.Overtime);
    }

    public enum State {
        Initial {
            @Override
            void process(StateMachine sm, Event e) {
                switch (e) {
                    case Submit:
                        this.exit(sm);
                        if (sm.context.getArrivalResult() == ReceptionRecord.ArrivalResult.无效) {
                            sm.state = Invalid;
                        } else {
                            // todo: [store.passengerFlow.enableAssign=true]/state=assigned
                            sm.state = Final;
                        }
                        sm.state.entry(sm);
                        break;
                    case Overtime:
                        this.exit(sm);
                        sm.state = Invalid;
                        sm.state.entry(sm);
                        break;
                }
            }
        },
        Invalid {
            @Override
            void process(StateMachine sm, Event e) {

            }
        },
        Assigned {
            @Override
            void process(StateMachine sm, Event e) {
                switch (e) {
                    case Submit:
                        this.exit(sm);
                        sm.state = Final;
                        sm.state.entry(sm);
                        break;
                }
            }
        },
        Final {
            @Override
            void process(StateMachine sm, Event e) {

            }
        };

        abstract void process(StateMachine sm, Event e);

        void entry(StateMachine sm) {
        }

        void exit(StateMachine sm) {
        }
    }
}