State Diagram
Berikut adalah state diagram dari mesin turnstile
Terdapat 2 state, yaitu LOCKED dan UNLOCKED. State awal adalah LOCKED. Panah pada gambar merupakan representasi dari perubahan suatu state. Untuk berubah state, maka perlu adanya event tertentu, misal memasukkan token/koin untuk menuju state unlocked.
Use Case
CRC
Turnstile
Responsibilities
|
Collaborator
|
Allow user to pass through the machine
|
UnlockedState
|
Allow user to insert token
|
|
Allow user to get refund
|
|
Turn on alarm
|
LockedState
Responsibilities
|
Collaborator
|
Set machine state to unlocked
|
Turnstile
|
UnlockedState
Responsibilities
|
Collaborator
|
Set machine state to locked
|
Turnstile
|
Deployment Diagram
Class Diagram
Source Code
Turnstile.java
public class Turnstile
{
private State state;
private final State lockedState;
private final State unlockedState;
public Turnstile()
{
lockedState = new LockedState(this);
unlockedState = new UnlockedState(this);
// set initial state of turnstile
state = lockedState;
}
public State getState()
{
return state;
}
public void setState(State state)
{
this.state = state;
}
public void insertToken()
{
state.insertToken();
}
public void passThru()
{
state.passThru();
}
public void lock()
{
System.out.println("Locking the turnstile...");
setState(lockedState);
System.out.println(getState());
}
public void unlock()
{
System.out.println("Unlocking the turnstile...");
setState(unlockedState);
System.out.println(getState());
}
public void alarm()
{
System.out.println("Alert! Cannot pass through without inserting a token!!");
}
public void refund()
{
System.out.println("Refunding the token...");
}
public String toString()
{
StringBuffer result = new StringBuffer();
result.append("\n-- Welcome to the Turnstile Application --\n");
result.append(getState());
return result.toString();
}
} State.java
public interface State
{
public void insertToken();
public void passThru();
}
UnlockedState.java
public class UnlockedState implements State
{
private final Turnstile turnstile;
public UnlockedState(Turnstile turnstile)
{
this.turnstile = turnstile;
}
public void insertToken()
{
System.out.println("insertToken(): Accepting token in the " + turnstile.getState() +
" state...");
turnstile.refund();
}
public void passThru()
{
System.out.println("passThru(): Passing through in the " + turnstile.getState() + " state...");
turnstile.lock();
}
public String toString()
{
return "UNLOCKED";
}
}
LockedState.java
public class LockedState implements State
{
private final Turnstile turnstile;
public LockedState(Turnstile turnstile)
{
this.turnstile = turnstile;
}
public void insertToken()
{
System.out.println("insertToken(): Accepting token in the " + turnstile.getState() +
" state...");
turnstile.unlock();
}
public void passThru()
{
System.out.println("passThru(): Passing through in the " + turnstile.getState() + " state....");
turnstile.alarm();
}
public String toString()
{
return "LOCKED";
}
}
Berikut adalah source code untuk client
TurnstileApp.java
import java.util.Scanner;
/**
* Created by A-BILAL on 12/18/2016.
*/
public class TurnstileApp
{
private TurnstileApp()
{
// using default private constructor in lieu of creating a Singleton object
}
public static void main(String[] args)
{
Turnstile turnstile = new Turnstile();
// first person inserts a token and passes through the turnstile
System.out.println(turnstile);
turnstile.insertToken();
turnstile.passThru();
// second person attempts to pass through turnstile without inserting a token
System.out.println(turnstile);
turnstile.passThru();
turnstile.insertToken();
turnstile.passThru();
// third person attempts to pass through turnstile without initially inserting a token.
System.out.println(turnstile);
turnstile.insertToken();
turnstile.insertToken();
turnstile.passThru();
while(true){
// System.out.println(turnstile);
Scanner reader = new Scanner(System.in); // Reading from System.in
System.out.println("Enter action (1 = Insert Token, 2 = Pass Through), 3 = Exit: ");
int n = reader.nextInt(); // Scans the next token of the input as an int.
if(n == 1){
turnstile.insertToken();
}
else if(n == 2){
turnstile.passThru();
}
else if(n == 3){
break;
}
else{
System.out.println("Input Tidak Valid");
}
}
}
}
Output
Terdapat 3 percobaan pada program client, yaitu :
- Memasukkan token dan melewati mesin turnstile
State akan berubah menjadi UNLOCKED dan mesin bisa terlewati lalu state akan kembali ke LOCKED - Mencoba melewati mesin turnstile tanpa memasukkan token
State tetap pada LOCKED dan tidak bisa melewati mesin serta terdapat pemanggilan fungsi alarm - Memasukkan token 2 kali
State pada mesin berubah menjadi UNLOCKED. Setelah memasukkan token ke-2 maka user akan mendapatkan refund. Setelah melewati mesin maka state kembali ke LOCKED.
Untuk input User :
- 1 = Insert Token
- 2 = Pass Through
Referensi :
