20. Memorandum Mode

Memorandum mode:

Memento: capture the internal state of an object without compromising encapsulation, and save the state outside the object. In order to restore the object to the original save state.

 

Demo:

// Memorandum Mode

Class Program

{

Static void main (string [] ARGs)

{

Originator o = new originator ();

O. State = "on ";

O. Show ();

// Instantiate the manager and save the status

Caretaker c = new caretaker ();

C. mement0 = O. creatememento ();

 

O. State = "off ";

O. Show ();

// Restore status

O. setmemento (C. mement0 );

O. Show ();

 

Console. readkey ();

}

}

 

Class Originator

{

Private string state; // saved attributes

Public String state

{

Get {return state ;}

Set {state = value ;}

}

Public memento creatememento () // create a memorandum to import and instantiate a memento object.

{

Return (new memento (State ));

}

Public void setmemento (memento) // restore Memorandum

{

State = memento. State;

}

Public void show ()

{

Console. writeline ("state =" + State );

}

}

 

// Memorandum

Class memento

{

Private string state;

Public memento (string state)

{

This. State = State;

}

Public String state

{

Get {return state ;}

}

}

 

// Manager class

Class caretaker

{

Private memento;

Public memento mement0 // get or set the Memorandum

{

Get {return memento ;}

Set {memento = value ;}

}

}