Use the design mode to solidify your C # Program (5-2)

Use the design mode to solidify your C # Program (5-1)

Design Patterns: Solidify Your C # Application Architecture with Design Patterns Chinese edition (Part 1)
Author: Samir Bajaj
Translator: glory

The following is a complete example of the state mode.

C # example:

Using System;

Abstract class State

{

Public virtual void AddNickel (VendingMachine vm ){}

Public virtual void AddDime (VendingMachine vm ){}

Public virtual void AddQuarter (VendingMachine vm ){}

Protected virtual void ChangeState (VendingMachine vm, State s)

{

Vm. ChangeState (s );

}

}

Class VendingMachine

{

Private State state;

Public VendingMachine ()

{

Console. WriteLine ("The Vending Machine is now online: product costs 25c ");

State = Start. Instance ();

}

Public void ChangeState (State)

{

State =;

}

Public void Vend ()

{

// Send a drink

Console. WriteLine ("Dispensing product... Thank you! ");

}

Public void AddNickel ()

{

State. AddNickel (this );

}

Public void AddDime ()

{

State. AddDime (this );

}

Public void AddQuarter ()

{

State. AddQuarter (this );

}

}

Class Start: State

{

Private static State state = new Start ();

Private Start ()

{

}

Public static State Instance ()

{

// Singleton Logic

Console. WriteLine ("Credit: 0c ");

Return state;

}

Public override void AddNickel (VendingMachine vm)

{

ChangeState (vm, Five. Instance ());

}

Public override void AddDime (VendingMachine vm)

{

ChangeState (vm, Ten. Instance ());

}

Public override void AddQuarter (VendingMachine vm)

{

Vm. Vend ();

}

}

Class Five: State

{

Private static State state = new Five ();

Private Five ()

{

}

Public static State Instance ()

{

// Singleton Logic

Console. WriteLine ("Credit: 5c ");

Return state;

}

Public override void AddNickel (VendingMachine vm)

{

ChangeState (vm, Ten. Instance ());

}

Public override void AddDime (VendingMachine vm)

{

ChangeState (vm, Fifteen. Instance ());

}

Public override void AddQuarter (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance (); // no change returned :-)

}

}

Class Ten: State

{

Private static State state = new Ten ();

Private Ten ()

{

}

Public static State Instance ()

{

// Singleton Logic

Console. WriteLine ("Credit: 10c ");

Return state;

}

Public override void AddNickel (VendingMachine vm)

{

ChangeState (vm, Fifteen. Instance ());

}

Public override void AddDime (VendingMachine vm)

{

ChangeState (vm, Twenty. Instance ());

}

Public override void AddQuarter (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance (); // no change returned :-)

}

}

Class Fifteen: State

{

Private static State state = new Fifteen ();

Private deleteen ()

{

}

Public static State Instance ()

{

// Singleton Logic

Console. WriteLine ("Credit: 15c ");

Return state;

}

Public override void AddNickel (VendingMachine vm)

{

ChangeState (vm, Twenty. Instance ());

}

Public override void AddDime (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance ());

}

Public override void AddQuarter (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance (); // no change returned :-)

}

}

Class Twenty: State

{

Private static State state = new Twenty ();

Private Twenty ()

{

}

Public static State Instance ()

{

// Singleton Logic

Console. WriteLine ("Credit: 20c ");

Return state;

}

Public override void AddNickel (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance ());

}

Public override void AddDime (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance ());

}

Public override void AddQuarter (VendingMachine vm)

{

Vm. Vend ();

ChangeState (vm, Start. Instance (); // no change returned :-)

}

}

Class Application

{

Public static void Main ()

{

Int coin = 0;

String input = null;

VendingMachine vm = new VendingMachine ();

While (true)

{

Console. Write ("Insert a coin (5, 10, 25 ):");

Input = Console. ReadLine ();

Coin = Int32.Parse (input );

Switch (coin)

{

Case 5:

Vm. AddNickel ();

Break;

Case 10:

Vm. AddDime ();

Break;

Case 25:

Vm. AddQuarter ();

Break;

Default:

Break;

}

}

}

}

/* The following is the output result of a running task:

The Vending Machine is now online: product costs 25c

Credit: 0c

Insert a coin <5, 10, 25>: 5

Credit: 5c

Insert a coin <5, 10, 25>: 10

Credit: 15c

Insert a coin <5, 10, 25>: 5

Credit: 20c

Insert a coin <5, 10, 25>: 5

Dispensing product... Thank you!

*/