Java Design Pattern: Abstract Factory

Abstract Factory pattern adds another layer of abstraction for Factory pattern. If we compare Abstract Factory with Factory, it is pretty obvious that a new layer of abstraction is added. Abstract Factory is a super-factory which creates other factories. We can call it 「Factory of factories」.

Abstract Factory class diagram

Abstract Factory Java code

interface CPU {
    void process();
}
 
interface CPUFactory {
	CPU produceCPU();
}
 
class AMDFactory implements CPUFactory {
    public CPU produceCPU() {
        return new AMDCPU();
    }
}
 
class IntelFactory implements CPUFactory {
    public CPU produceCPU() {
        return new IntelCPU();
    }
}
 
class AMDCPU implements CPU {
    public void process() {
        System.out.println("AMD is processing...");
    }
}
 
class IntelCPU implements CPU {
    public void process() {
        System.out.println("Intel is processing...");
    }
}
 
class Computer {
	CPU cpu;
 
    public Computer(CPUFactory factory) {
    	cpu = factory.produceCPU();
        cpu.process();
    }
}
 
public class Client {
    public static void main(String[] args) {
        new Computer(createSpecificFactory());
    }
 
    public static CPUFactory createSpecificFactory() {
        int sys = 0; // based on specific requirement
        if (sys == 0) 
        	return new AMDFactory();
        else 
        	return new IntelFactory();
    }
}

Real use example

Actually, this is a very important concept of modern frameworks. Here is a question about this.