Clean Architecture & Design Patterns in Practice · Pelajaran

Mediator dan Chain of Responsibility

Jelajahi dua pattern perilaku yang memisahkan pengirim dari penerima: Mediator memusatkan komunikasi, sedangkan Chain of Responsibility meneruskan permintaan melalui rangkaian pengendali.

Mediator dan Chain of Responsibility adalah pelajaran Clean Architecture & Design Patterns in Practice gratis di CoddyKit. Ini adalah pelajaran 4 dari 4. Kamu bisa membaca pelajaran lengkapnya di bawah secara gratis — lalu praktikkan langsung di browser dengan editor kode bawaan dan tutor AI 24/7. Ini adalah bagian dari jalur belajar Clean Architecture & Design Patterns in Practice, dan progresmu tersinkronisasi di web dan aplikasi CoddyKit. Kursus Clean Architecture & Design Patterns in Practice mencakup 4 pelajaran total.

Bagian dari pelajaran ini belum diterjemahkan dan ditampilkan dalam bahasa Inggris.

Two Ways to Decouple Communication

Objects often need to talk to each other, but direct references create tangled webs of dependencies.

This lesson covers two behavioral solutions:

Mediator routes all communication through a central hub.
Chain of Responsibility passes a request down a line until someone handles it.

The Mediator Problem

Imagine a dialog with buttons, checkboxes, and text fields all reacting to each other. If every widget references every other widget, the coupling explodes.

Mediator replaces this mesh with a star: each widget talks only to the mediator.

Mediator Interface

The mediator defines how components notify it of events.

interface Mediator {
    void notify(Component sender, String event);
}

Concrete Mediator

The concrete mediator contains the coordination logic that used to be scattered.

class Dialog implements Mediator {
    Button submit;
    Checkbox terms;
    public void notify(Component sender, String event) {
        if (sender == terms && event.equals("toggle")) {
            submit.setEnabled(terms.isChecked());
        }
    }
}

Components Stay Dumb

Each component simply reports events to the mediator and reacts to instructions. It does not know about its siblings.

class Checkbox {
    Mediator mediator;
    boolean checked;
    void toggle() {
        checked = !checked;
        mediator.notify(this, "toggle");
    }
    boolean isChecked() { return checked; }
}

When to Use Mediator

Components are tightly interconnected.
Reuse is hard because objects depend on many others.
Behavior is spread across classes and hard to change.

Beware: the mediator itself can grow into a god object if overloaded.

The Chain of Responsibility Problem

Now a different scenario: a request might be handled by one of several processors, and you do not want the sender to know which.

Examples: middleware pipelines, event bubbling, approval workflows.

Handler Interface

Each handler can process a request or pass it to the next handler.

abstract class Handler {
    protected Handler next;
    Handler setNext(Handler n) { this.next = n; return n; }
    abstract void handle(Request r);
}

A Concrete Handler

A handler decides whether it can deal with the request; otherwise it forwards.

class AuthHandler extends Handler {
    void handle(Request r) {
        if (!r.authenticated) {
            System.out.println("Rejected: not authenticated");
            return;
        }
        if (next != null) next.handle(r);
    }
}

Building and Running the Chain

Handlers are linked, then the request enters at the head.

class Request { boolean authenticated = true; }
abstract class H { H next; H link(H n){next=n;return n;} abstract void handle(Request r); }
class Log extends H { void handle(Request r){ System.out.println("logged"); if(next!=null) next.handle(r);} }
class Done extends H { void handle(Request r){ System.out.println("handled"); } }
public class Main {
  public static void main(String[] a){
    H head = new Log();
    head.link(new Done());
    head.handle(new Request());
  }
}

Comparing the Two

Mediator: many-to-many coordination through one hub; bidirectional.
Chain: a one-directional pipeline; each link is independent and order matters.

Both decouple senders from receivers, but solve different shapes of problem.

Quick Check

Test your understanding of these two patterns.

Recap

You learned two communication-decoupling patterns.

Mediator turns a mesh of dependencies into a star around a coordinator.
Chain of Responsibility forwards a request along independent handlers until one handles it.

Pertanyaan yang Sering Diajukan

Apakah pelajaran “Mediator dan Chain of Responsibility” gratis?

Ya — teks lengkap “Mediator dan Chain of Responsibility” gratis dibaca di sini di web. Untuk praktiknya secara interaktif (editor kode bawaan dan tutor AI 24/7) dan buka sisa kursus Clean Architecture & Design Patterns in Practice, upgrade ke CoddyKit PRO. Kursus Clean Architecture & Design Patterns in Practice mencakup 4 pelajaran total.

Apa yang akan aku pelajari di “Mediator dan Chain of Responsibility”?

Jelajahi dua pattern perilaku yang memisahkan pengirim dari penerima: Mediator memusatkan komunikasi, sedangkan Chain of Responsibility meneruskan permintaan melalui rangkaian pengendali. Kamu berlatih Clean Architecture & Design Patterns in Practice dengan kode praktik yang langsung kamu jalankan di browser, dan tutor AI 24/7 menjawab pertanyaanmu saat kamu mengerjakan pelajaran ini.

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