850: Mainline

Having defined the interface, you proceed to define the class. The new class, like the Movie class, is an observable, with a setter that activates observers when the movie vector is set, and a miscellaneous method, changed that activates observers when called.

import java.util.*; 
public class MovieData extends Observable implements MovieDataInterface { 
 private Vector vector; 
 public MovieData () { 
  setMovieVector(MovieAuxiliaries.readMovieFile("general.movies"));      
 } 
 public void setMovieVector (Vector v) { 
  vector = v; 
  setChanged(); 
  notifyObservers(); 
 } 
 public Vector getMovieVector () { 
  return vector; 
 } 
 public Movie getMovie (int i) { 
  if (i >= 0 && i <= vector.size()) { 
   return (Movie)(vector.elementAt(i)); 
  } 
  else {return null;} 
 } 
 public void changed () { 
  setChanged(); 
  notifyObservers(); 
 } 
}