Proxy dp

Proxy_impl.java

public interface Service {

	void insert();
	
}

public class RealService implements Service{

	@Override
	public void insert() {
		System.out.println("Insert");
	}
	
}

public class Proxy implements Service{

	private RealService realService;
	
	@Override
	public void insert() {
		if(realService==null) {
		   realService = new RealService();
		}
		System.out.println("action before");
		realService.insert();
		System.out.println("action after");
	}

}

public class Client {
	
	public static void main(String[] args) {
		Service service  = new Proxy();
		service.insert();
	}

}