브리지 패턴

ynkim·2024년 12월 12일

브리지

큰 클래스 또는 밀접하게 관련된 클래스들의 집합을 두 개의 계층구조로 나눈 뒤 독립적으로 개발할 수 있도록 하는 패턴

구조

추상화: 구현 객체에 의존해 실제 하위 작업들을 수행
구현: 모든 구상 구현들에 공통적인 인터페이스를 선언하며 추상화는 여기에 선언된 메서드들을 통해서만 구현 객체와 소통 가능
구상 구현: 플랫폼별 맞춤형 코드를 포함
정제된 추상화: 제어 논리의 변형들을 제공

예시 코드

public interface Device {
    boolean isEnabled();

    void enable();

    void disable();

    int getVolume();

    void setVolume(int percent);

    int getChannel();

    void setChannel(int channel);

    void printStatus();
}

public class Radio implements Device {
    private boolean on = false;
    private int volume = 30;
    private int channel = 1;

    @Override
    public boolean isEnabled() {
        return on;
    }

    @Override
    public void enable() {
        on = true;
    }

    @Override
    public void disable() {
        on = false;
    }

    @Override
    public int getVolume() {
        return volume;
    }

    @Override
    public void setVolume(int volume) {
        if (volume > 100) {
            this.volume = 100;
        } else if (volume < 0) {
            this.volume = 0;
        } else {
            this.volume = volume;
        }
    }

    @Override
    public int getChannel() {
        return channel;
    }

    @Override
    public void setChannel(int channel) {
        this.channel = channel;
    }

    @Override
    public void printStatus() {
        System.out.println("------------------------------------");
        System.out.println("| I'm radio.");
        System.out.println("| I'm " + (on ? "enabled" : "disabled"));
        System.out.println("| Current volume is " + volume + "%");
        System.out.println("| Current channel is " + channel);
        System.out.println("------------------------------------\n");
    }
}

public class Tv implements Device {
    private boolean on = false;
    private int volume = 30;
    private int channel = 1;

    @Override
    public boolean isEnabled() {
        return on;
    }

    @Override
    public void enable() {
        on = true;
    }

    @Override
    public void disable() {
        on = false;
    }

    @Override
    public int getVolume() {
        return volume;
    }

    @Override
    public void setVolume(int volume) {
        if (volume > 100) {
            this.volume = 100;
        } else if (volume < 0) {
            this.volume = 0;
        } else {
            this.volume = volume;
        }
    }

    @Override
    public int getChannel() {
        return channel;
    }

    @Override
    public void setChannel(int channel) {
        this.channel = channel;
    }

    @Override
    public void printStatus() {
        System.out.println("------------------------------------");
        System.out.println("| I'm TV set.");
        System.out.println("| I'm " + (on ? "enabled" : "disabled"));
        System.out.println("| Current volume is " + volume + "%");
        System.out.println("| Current channel is " + channel);
        System.out.println("------------------------------------\n");
    }
}

public interface Remote {
    void power();

    void volumeDown();

    void volumeUp();

    void channelDown();

    void channelUp();
}

public class BasicRemote implements Remote {
    protected Device device;

    public BasicRemote() {}

    public BasicRemote(Device device) {
        this.device = device;
    }

    @Override
    public void power() {
        System.out.println("Remote: power toggle");
        if (device.isEnabled()) {
            device.disable();
        } else {
            device.enable();
        }
    }

    @Override
    public void volumeDown() {
        System.out.println("Remote: volume down");
        device.setVolume(device.getVolume() - 10);
    }

    @Override
    public void volumeUp() {
        System.out.println("Remote: volume up");
        device.setVolume(device.getVolume() + 10);
    }

    @Override
    public void channelDown() {
        System.out.println("Remote: channel down");
        device.setChannel(device.getChannel() - 1);
    }

    @Override
    public void channelUp() {
        System.out.println("Remote: channel up");
        device.setChannel(device.getChannel() + 1);
    }
}

public class AdvancedRemote extends BasicRemote {

    public AdvancedRemote(Device device) {
        super.device = device;
    }

    public void mute() {
        System.out.println("Remote: mute");
        device.setVolume(0);
    }
}

public class Demo {
    public static void main(String[] args) {
        testDevice(new Tv());
        testDevice(new Radio());
    }

    public static void testDevice(Device device) {
        System.out.println("Tests with basic remote.");
        BasicRemote basicRemote = new BasicRemote(device);
        basicRemote.power();
        device.printStatus();

        System.out.println("Tests with advanced remote.");
        AdvancedRemote advancedRemote = new AdvancedRemote(device);
        advancedRemote.power();
        advancedRemote.mute();
        device.printStatus();
    }
}