Strategy Pattern

2023-10-11 in Design Patterns

Strategy Pattern에 대해 설명하는 페이지입니다.

Environment

• Programming Language: Java

Index

• Index
• Introduction
• How to Use (Example)
• Comments

Introduction

• Purpose
  • Defines a set of encapsulated algorithms that can be swapped to carry out a specific behavior.
• Use When
  • The only difference between many related classes is their behavior.
  • Multiple versions or variations of an algorithm are required.
  • The behavior of a class should be defined at runtime.
  • Conditional statements are complex and hard to maintain.

How to Use (Example)

public interface FlyBehavior {
    public void fly();
}

public class FlyWithWings implements FlyBehavior {
    public void fly() {
        System.out.println("I'm flying.");
    }
}

public class FlyNoWay implements FlyBehavior {
    public void fly() {
        System.out.println("I can't fly.");
    }
}

public abstract class Bird {
    FlyBehavior flyBehavior;

    public Bird() {}

    public void performFly() {
        flyBehavior.fly();
    }
}

public class MyBird extends Bird {
    public MyBird() {
        flyBehavior = new FlyNoWay();
    }

    public void setFlyBehavior(FlyBehavior flyBehavior) {
        this.flyBehavior = flyBehavior();
    }
}

public class Main {
    public static void main(String[] args) {
        Bird myBird = new MyBird();
        myBird.performFly();  // "I can't fly."

        myBird.setFlyBehavior(new FlyWithWings());
        myBird.performFly();  // "I'm flying."
    }
}

Comments

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