Bridge Pattern

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

Adapter: Put old class into a new class implement Interface 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
    }
}