Coordinates various actions and fires a callback when all are complete

Coordinator.java

import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;

public class Coordinator {

  private List<String> actions;
  private Set<String> completedActions = new TreeSet<>();
  private CoordinatorCompleteAction coordinatorCompleteAction;

  public Coordinator(CoordinatorCompleteAction coordinatorCompleteAction, String... actions) {
    if (coordinatorCompleteAction == null) {
      throw new NullPointerException("Coordinate complete action must not be null");
    }
    if (actions == null || actions.length == 0) {
      throw new IllegalArgumentException("No actions configured");
    }
    this.coordinatorCompleteAction = coordinatorCompleteAction;
    this.actions = Arrays.asList(actions);
  }

  public void completeAction(String action) {
    if (actions.contains(action)) {
      completedActions.add(action);
      checkComplete();
    }
  }

  public void reset() {
    completedActions.clear();
  }

  private void checkComplete() {
    if (actions.size() == completedActions.size()) {
      coordinatorCompleteAction.onCoordinatorComplete();
    }
  }

  public static interface CoordinatorCompleteAction {
    public void onCoordinatorComplete();
  }
}

CoordinatorSample

public class CoordinatorSample {
  private static final String ACTION_1 = "ACTION_1";
  private static final String ACTION_2 = "ACTION_2";
  
  Coordinator coordinator = new Coordinator(new CoordinatorCompleteAction() {
    launchMyAwesomeAction();
  }, ACTION_1, ACTION_2);
  
  public void sampleMethod() {
    doSomeAsyncWork.callback(onComplete() {
      coordinator.completeAction(ACTION_1);
    }
    
    doSomeAsyncWork.callback(onComplete() {
      coordinator.completeAction(ACTION_2);
    }
  }
}