Bridge Pattern

Bridge = “separate abstraction and implementation so both can change independently”

Adapter: use a old class into another new class, when call new method then call old method of old class inside. Factory Method and Bridge pattern are the same same. Put Interface into Abstract class.

• Factory Method
  • Define Interface via abstract method
  • Logic call Interface in normal method at Abstract Class
• Bridge pattern:
  • Define Interface via Constructor and got Abstract method
  • logic call Interface in Concrete class that extends Abstract class

Example

// Implementation hierarchy
interface Device {
    void turnOn();
    void turnOff();
}

class TV implements Device {
    public void turnOn() { System.out.println("TV on"); }
    public void turnOff() { System.out.println("TV off"); }
}

class Radio implements Device {
    public void turnOn() { System.out.println("Radio on"); }
    public void turnOff() { System.out.println("Radio off"); }
}

// Abstraction
abstract class RemoteControl {
    protected Device device;

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

    abstract void togglePower();
}

// Refined abstraction
class BasicRemote extends RemoteControl {
    public BasicRemote(Device device) {
        super(device);
    }

    void togglePower() {
        device.turnOn(); // bridge to implementation
    }
}