observer pattern sample

readme.md

observer pattern sample

Created with <3 with dartpad.dev.

main.dart

void main() {
  Miro miro = Miro();
  Student jason = Jason();
  Student bera = Bera();
 
  miro.subscribe(jason);
  miro.subscribe(bera);
  
  miro.speak();
}


abstract class Teacher{
  void notify(String msg){}
  void subscribe(Student s){}
  void unsubscribe(Student s){}
}

class Miro extends Teacher{
  List<Student> students = [];
  @override
  void notify(String msg){
    for(var s in students){
      s.update(msg);
    }
    
  }
  
  @override
  void subscribe(Student s){
    students.add(s);
  }
  
  @override
  void unsubscribe(Student s){
    students.remove(s);
  }
  
  void speak(){
    notify('와랏');
  }
}


abstract class Student{
  void update(String msg);
}


class Jason extends Student{
  @override
  void update(String msg){
    print('jason: $msg');
  }
}
class Bera extends Student{
  @override
  void update(String msg){
    print('Bera : $msg');
  }
}