Proxy

Here is a common interface that the proxy and service
must share. (They could have shared a superclass instead).
-----------------------------------------------------
public interface IService{
    public String doIt(int value);
}
-----------------------------------------------------


Here is the service providing class
-----------------------------------------------------
class Service implements IService{
    public String doIt(int temp){
        return "I preformed some service for you";
    }
}
-----------------------------------------------------

Here is the proxy class. 
The proxy here is providing a security layer to calls 
made to the service. (It does not like the int 2)
Proxy classes are commonly used for some type of
service managment.
-----------------------------------------------------
class ServiceProxy implements IService{
    private Service service = new Service();
    public String doIt(int temp){
        if(temp==2)
            return "I refuse";
        else
            return service.doIt(temp);
    }
}
-----------------------------------------------------

Here is the test class that simply demonstrates the 
function of the proxy class.
-----------------------------------------------------
class Test{

    public static void main(String[] args){
        System.out.println("class: Test, method: main\n");
        
        IService serviceProxy = new ServiceProxy();
        IService service = new Service();

        System.out.println("calling service and proxy with arg of 1");        
        System.out.println("service: " + service.doIt(1));
        System.out.println("proxy: " + serviceProxy.doIt(1));

        System.out.println("");        

        System.out.println("calling service and proxy with arg of 2");        
        System.out.println("service: " + service.doIt(2));
        System.out.println("proxy: " + serviceProxy.doIt(2));
    }
}
-----------------------------------------------------


Here is a tar with above classes in it. 
proxy.tar