Factory Method - Creational Design Pattern

🏭 Factory Method

It provides a way to delegate the instantiation logic to child classes. Example:

interface Interviewer {
   public function takeInterview();
}
class Developer implements Interviewer {
    public function askQuestions() {
        // 'Ask Programming Question!';
    }
}
class CommunityExecutive implements Interviewer {
    public function askQuestions() {
        // 'Ask about Community Building!';
    }
}
abstract class HiringManager {
    abstract protected makeInterviewer();
    public function takeInterviews() {
        Interviewer interviewer = this.makeInterviewer();
        interviewer.askQuestions();
    }
}
// any child can extend it and provide the required interviewer
class DevelopmentManager extends HiringManager {
    protected Interviewer makeInterviewer() {
        return new Developer();
    }
}
class MarketingManager extends HiringManager {
    protected Interviewer makeInterviewer() {
        return new CommunityExecutive();
    }
}

When to Use? Useful when there is some generic processing in a class but the required sub-class is dynamically decided at runtime. Or putting it in other words, when the client doesn’t know what exact sub-class it might need.