Adapter Pattern

Adapter Pattern에 대해 설명하는 페이지입니다.

Posted Oct 18, 2023

By HyunJinNo

Tags

Design Pattern, Java

1. Introduction

• a.k.a
  • Wrapper
• Purpose
  • Permits classes with different interfaces to work together by creating a common object by which they may communicate and interact.
• Use When
  • A class to be used doesn't meet interface requirements.
• Mechanism
  • A client makes a request to the adapter by calling a method on it using the target interface.
  • The adapter translates the request into one or more calls on the adaptee using the adaptee interface.
  • The client receives the results of the call and never knows there is an adapter doing the translation.
• Motivation
  • A toolkit or class library may have an interface which is incompatible with an application's interface we want to integrate.
  • It's possible that we don't have access to the source code of the toolkit or library.
  • Even if the source code is available, we may want to minimize the change.
• Summary
  • Converts the interface of a class into another interface clients expect.
  • Lets classes work together that couldn't otherwise because of incompatible interfaces.
  • Class adapter and object adapter

2. How to Use (Example)

• Target Interface

  java

  1public interface Duck {
  2    public void quack();
  3    public void fly();
  4}
  5
  6public class MallardDuck implements Duck {
  7    public void quack() {
  8        System.out.println("Quack.");
  9    }
  10    public void fly() {
  11        System.out.println("I'm flying.");
  12    }
  13}

• Adaptee Interface

  java

  1public interface Turkey {
  2    public void gobble();
  3    public void fly();
  4}
  5
  6public class WildTurkey implements Turkey {
  7    public void gobble() {
  8        System.out.println("Gobble.");
  9    }
  10    public void fly() {
  11        System.out.println("I'm flying.");
  12    }
  13}

• Object Adapter

  java

  1public class TurkeyAdapter implements Duck {
  2    Turkey turkey; // adaptee
  3    public TurkeyAdapter(Turkey turkey) {
  4        this.turkey = turkey;
  5    }
  6    public void quack() {
  7        turkey.gobble();
  8    }
  9    public void fly() {
  10        for (int i = 0; i < 5; i++) {
  11            turkey.fly();
  12        }
  13    }
  14}