Enum enumeration writes a simple state machine

Today is raining, the mood is a little depressed, therefore uses the enumeration to write a state machine to resolve the mood, by the way the enumeration uses the method.

 PackageStateMachine;Importjava.util.ArrayList;Importjava.util.List;/** *  * @authorZhenweilai **/ Public enumStateenum {Ready ("1", "Ready") {@OverridevoidSubmit (Entity entity) {Super. Submit (entity); //rewrite the update state method to add your own business logicSystem.out.println ("Ready to submit the finishing touches ..."); }}, START ("2", "Start") {@OverridevoidUndo (Entity entity) {Super. Undo (entity); System.out.println ("Start Undo Finishing work ..."); }}, RUN ("3", "Run"), STOP ("4", "Stop"); //Status Code    PrivateString Code; //Status Name    PrivateString name; //Construction MethodStateenum (string code, string name) { This. Code =Code;  This. Name =name; //Register code in the list when constructingStateList.stateList.add (code); }    //update the state of the method, if the update state needs to do something else, then override the method, then super call, and then add your own logic    voidSubmit (Entity entity) {if(entity.getstate () = =NULL&&! This. GetCode (). Equals (Ready.getcode ()))Throw NewRuntimeException ("Status not valid"); Else if(entity.getstate () = =NULL&& This. GetCode (). Equals (Ready.getcode ())) {Entity.setstate (StateList.stateList.get (0)); return; }                    if(! StateList.stateList.get ((StateList.stateList.indexOf (Entity.getstate ()) +1). Equals ( This. Code)) Throw NewRuntimeException ("Status not valid"); if(StateList.stateList.contains ( This. Code)) {Entity.setstate ( This. Code); }    }    //anti-operation method, same as submission method    voidUndo (Entity entity) {//throws an exception if there is currently no state and is not the current enumeration state        if(entity.getstate () = =NULL||! Entity.getstate (). Equals ( This. Code)) Throw NewRuntimeException ("Status not valid"); //determine if the legal state of the list has been registered            if(StateList.stateList.contains ( This. Code)) {Integer Codeindex= StateList.stateList.indexOf ( This. Code); //if it is not initialized, fallback to a state, otherwise set to null                if(codeindex>0) entity.setstate (StateList.stateList.get (--codeindex)); ElseEntity.setstate (NULL); }    }        //get the state name according to code     Public Staticstring Getnamebycode (String code) { for(Stateenum item:StateEnum.values ()) {if(Item.getcode (). Equals (code)) {returnItem.getname (); }        }         return""; }        /**     *      * @authorZhenweilai * Static inner class, very eco-friendly, in order to use this static list * Because the enumeration constructor method cannot call the static property, the reason is unknown, know the person please tell me*/    Static classstatelist{Private StaticList<string> statelist =NewArraylist<>(); }        //------------------------------------------------------Getter Setter-------------------------------------------------------------------------         PublicString GetCode () {returnCode; }     Public voidSetcode (String code) { This. Code =Code; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }}

 PackageStateMachine;/** *  * @authorZhenweilai * Entity*/ Public classEntity {//Status Code    PrivateString State; /*** Get Status code translation *@return     */     PublicString Getstatename () {returnStateenum.getnamebycode ( This. State); }         PublicString getState () {returnState ; }         Public voidsetState (String state) { This. State =State ; }}

 PackageStateMachine;/** *  * @authorZhenweilai **/ Public classTestClass {/*** Test method *@paramargs*/     Public Static voidMain (string[] args) {Entity entity=NewEntity ();        StateEnum.READY.submit (entity);        System.out.println (Entity.getstatename ());        StateEnum.START.submit (entity);        System.out.println (Entity.getstatename ());        StateEnum.RUN.submit (entity);        System.out.println (Entity.getstatename ());        StateEnum.STOP.submit (entity);                System.out.println (Entity.getstatename ());        StateEnum.STOP.undo (entity);        System.out.println (Entity.getstatename ());        StateEnum.RUN.undo (entity);        System.out.println (Entity.getstatename ());        StateEnum.START.undo (entity);        System.out.println (Entity.getstatename ());        StateEnum.READY.undo (entity);        System.out.println (Entity.getstatename ()); }}

Console output Results:

Ready to submit the finishing touches ... Ready to start running stop running start undo finishing work ... Get ready

Enum enumeration writes a simple state machine