Mixin

Mixin specifications are evolving in Dart . Keep up to date with the specification and documentation

language/accepted/2.1/super-mixins/feature-specification.md at master · dart-lang/languageGitHub

Introduction to mixin

• Mixin can't have constructors

• Mixin can't be instantiated

• It's a way of injecting code into a class

void main() {
  // Mixins
​
//   var manager1 = Manager();
​
//   manager1.manageproject();
​
//   manager1.work();
​
  var ceo1 = CEO();
​
  ceo1.manageproject();
  ceo1.work();
  ceo1.recruit();
}
​
class Employee {
  void work() {
    print("Work");
  }
}
​
class HR extends Employee {
  void recruit() {
    print("Recruit Employee");
  }
}
​
class Manager extends Employee with CanManageProject {}
​
class CEO extends HR with CanManageProject {}
​
mixin CanManageProject {
  void manageproject() {
    print("manage project");
  }
}
​

The Problem

Solution using mixin

Mixin in Inheritance hierarchy

void main() {
  // Mixins

//   var manager1 = Manager();

//   manager1.manageproject();

//   manager1.work();

  var ceo1 = CEO();

  ceo1.startproject();
}

class Employee {
  void work() {
    print("Work");
  }
}

class HR extends Employee {
  void recruit() {
    print("Recruit Employee");
  }

  void keeplog() {
    print("keep log for recurit ");
  }
}

class Manager extends Employee with CanManageProject {}

class CEO extends HR with ExecutiveDecision, CanManageProject {
  void startproject() {
    manageproject();

    keeplog();
  }
}

mixin CanManageProject {
  void manageproject() {
    print("manage project");
  }

  void keeplog() {
    print("Log for managing project");
  }
}

mixin ExecutiveDecision {
  void decision() {
    print("Executive Decision");
  }

  void keeplog() {
    print("Log for Executive Decision");
  }
}

"on" Keyword

void main() {
  var ceo1 = CEO();

  ceo1.startproject();
}

class Employee {
  void work() {
    print("Work");
  }
}

class HR extends Employee {
  void recruit() {
    print("Recruit Employee");
  }

  void keeplog() {
    print("keep log for recurit ");
  }
}

class Manager extends Employee with CanManageProject {}

class CEO extends HR with ExecutiveDecision, CanManageProject {
  void startproject() {
    manageproject();

    keeplog();
  }
}

class CTO extends HR with ExecutiveDecision, CanManageProject {}

mixin CanManageProject {
  void manageproject() {
    print("manage project");
  }

  void keeplog() {
    print("Log for managing project");
  }
}

mixin ExecutiveDecision on HR {
  void decision() {
    print("Executive Decision");
  }

  void keeplog() {
    print("Log for Executive Decision");
  }
}