Delegations no Kotlin (Medium)

1-interfaces.java

interface Loggable {
  public void log(String message);
}

class ConsoleLogger implements Loggable {
  @Override
  public void log(String message) {
     System.out.println("Message");
  }
}

class ToastLogger implements Loggable {
  Context context;

  public ToastLogger(Context context) {
     this.context = context;
  }

  @Override
  public void log(String message) {
     Utils.showToast(context, message);
  }
}

2-implementation.java

class Worker implements Loggable {
   public Loggable logger;

   public Worker(Loggable logger) {
       this.logger = logger;
   }

   @Override
   public void log(String message) {
       logger.log(message);
   }

   public void doWork() {
       log("Working");
       //..
       log("Work done");
   }
}

Worker worker = new Worker(new ConsoleLogger());
worker.logger = new ToastLogger(getContext());
worker.doWork();