Front Controller Design Pattern - Implementation

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Front Controller Design Pattern - Implementation - Class Diagram

UserView.java

public class UserView
{
public void show()
{
System.out.println("Displaying User Page");
}
}

SalaryView.java

public class SalaryView
{
public void show()
{
System.out.println("Displaying Salary Page");
}
}

AccountView.java

public class AccountView
{
public void show()
{
System.out.println("Displaying Account Page");
}
}

Dispatcher.java

public class Dispatcher
{
private SalaryView  salaryView;
private UserView    userView;
private AccountView accountView;

public Dispatcher()
{
salaryView = new SalaryView();
userView = new UserView();
accountView = new AccountView();
}

public void dispatch( String request )
{
if( request.equalsIgnoreCase("USER") )
{
userView.show();
}
else if( request.equalsIgnoreCase("ACCOUNT") )
{
accountView.show();
}
else
{
salaryView.show();
}
}
}

FrontController.java

public class FrontController
{
private Dispatcher dispatcher;

public FrontController()
{
dispatcher = new Dispatcher();
}

private boolean isAuthenticUser()
{
//here you have to write Authentication logic
System.out.println("User is authenticated successfully.");
return true;
}

private void trackRequest( String request )
{
System.out.println("Page requested: " + request);
}

public void dispatchRequest( String request )
{
// log each request
trackRequest(request);
// authenticate the user
if( isAuthenticUser() )
{
dispatcher.dispatch(request);
}
}
}

FrontControllerPatternDemo.java

public class FrontControllerPatternDemo

{

public static void main( String[] args )

{

FrontController frontController = new FrontController();

frontController.dispatchRequest("USER");

System.out.println();

frontController.dispatchRequest("ACCOUNT");

System.out.println();

frontController.dispatchRequest("SALARY");

}

}

Output

Page requested: USER

User is authenticated successfully.

Displaying User Page

Page requested: ACCOUNT

User is authenticated successfully.

Displaying Account Page

Page requested: SALARY

User is authenticated successfully.

Displaying Salary Page

See also:

Front Controller Design Pattern - Introduction

Front Controller Design Pattern - Class and Sequence Diagram

Front Controller Design Pattern - Key Points

All Design Patterns Links