Design Pattern---Memo mode

Basic definition

Memo mode: Captures the internal state of an object without compromising encapsulation, and saves the state outside that object. The object can then be restored to its previously saved state.

Explanation: Simply put, you can save an object in a particular state at a certain point in time and restore the object to its saved state at a later time.

Basic code:

classOriginator {Private stringState ;  Public stringState {Get{returnState ;} Set{state =value;} }         PublicMemento Creatememento () {return NewMemento (state); }         Public voidSetmemento (Memento Memento) { state=Memento.        State; }         Public voidDisplay () {Console.WriteLine ("state="+State ); }    }    classMemento {Private stringState ;  Public stringState {Get{returnState ;} }         PublicMemento (stringState ) {             This. State =State ; }    }    classCaretaker {PrivateMemento memento1;  PublicMemento Memento1 {Get{returnmemento1;} Set{memento1 =value;} }    }

classOriginator {Private stringState ;  Public stringState {Get{returnState ;} Set{state =value;} }         PublicMemento Creatememento () {return NewMemento (state); }         Public voidSetmemento (Memento Memento) { state=Memento.        State; }         Public voidDisplay () {Console.WriteLine ("state="+State ); }    }    classMemento {Private stringState ;  Public stringState {Get{returnState ;} }         PublicMemento (stringState ) {             This. State =State ; }    }    classCaretaker {PrivateMemento memento1;  PublicMemento Memento1 {Get{returnmemento1;} Set{memento1 =value;} }    }

Client calls:

New originator ();             "  on " ;            Originator. Display ();             New caretaker ();             = originator. Creatememento ();             " off " ;            Originator. Display ();            Originator. Setmemento (caretaker. MEMENTO1);            Originator. Display ();

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List specific examples:

Play the game, save a character in the state before hitting the boss, to hit the boss after the end of the state before returning to it.

classProgram {Static voidMain (string[] args) {Role Role=NewRole ( -, -); Console.WriteLine ("before the war:"); Role.            Display (); Caretaker caretaker=Newcaretaker (); Caretaker.memento=role.            Savememento (); Role. Setbloodflow ( -); Role. Setmagicpoint ( -); Console.WriteLine ("War"); Role.            Display (); Role. Restorememento (caretaker.            Getmemento ()); Console.WriteLine ("Recovery"); Role.            Display ();        Console.read (); }    }    classRole {Private intBloodflow; Private intMagicPoint;  PublicRole (intBloodflow,intMagicPoint) {             This. Bloodflow =Bloodflow;  This. MagicPoint =MagicPoint; }         Public intGetbloodflow () {returnBloodflow; }         Public voidSetbloodflow (intbloodflow) {             This. Bloodflow =Bloodflow; }         Public intGetmagicpoint () {returnMagicPoint; }         Public voidSetmagicpoint (intMagicPoint) {             This. MagicPoint =MagicPoint; }         Public voidDisplay () {Console.WriteLine ("user's current status:"); Console.WriteLine ("Blood Volume:"+ getbloodflow () +"; Blue Quantity:"+getmagicpoint ()); }         PublicMemento Savememento () {return NewMemento (Getbloodflow (), Getmagicpoint ()); }         Public voidRestorememento (Memento Memento) { This. Bloodflow =Memento.            Getbloodflow ();  This. MagicPoint =Memento.        Getmagicpoint (); }    }    classMemento {Private intBloodflow; Private intMagicPoint;  PublicMemento (intBloodflow,intMagicPoint) {             This. Bloodflow =Bloodflow;  This. MagicPoint =MagicPoint; }         Public intGetbloodflow () {returnBloodflow; }         Public voidSetbloodflow (intbloodflow) {             This. Bloodflow =Bloodflow; }         Public intGetmagicpoint () {returnMagicPoint; }         Public voidSetmagicpoint (intMagicPoint) {             This. MagicPoint =MagicPoint; }    }    classCaretaker { PublicMemento Memento;  PublicMemento Getmemento () {returnMemento; }         Public voidSetmemento (Memento Memento) { This. Memento =Memento; }    }

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The advantages and disadvantages of Memo mode and its application scenario:

Advantages:

Provide users with a mechanism to restore the state, the user is more convenient to revert to a historical state.

Hide recovery details, the user does not need to care about the status of the save details.

Disadvantages:

The object state needs to be fully stored in the memo object, and if the state data is large, the memo object is very memory-intensive on resource consumption.

Applicable scenarios:

In short, the memo pattern can be used where the advantages of the show are avoided.

Design Pattern---Memo mode