988: Mainline

All that remains is to define the observer class, MovieDataObserverForTable, that connects model changes to the table.

The new observer checks all the movies to see which already are recorded in the table; it adds all the movies that it does not find. It checks for movies in the table with a private predicate, present. One argument of the private predicate is a vector of row vectors that you obtain using getDataVector; the first element of each such row vector is a movie title.

When the observer does add a new row vector, each element in the row vector must be a class instance; thus, int values must be wrapped in Integer instances. JTable procedures know how to deal with both String and Integer instances, but they are flummoxed by int values, because only class instances can be tested for class identity.

import java.util.*; 
import javax.swing.*;                            
import javax.swing.event.*;  
import javax.swing.table.*;                            
public class MovieDataObserverForTable implements Observer {  
 MovieTableApplication applet; 
 public MovieDataObserverForTable (MovieTableApplication a) { 
  applet = a; 
 } 
 public void update (Observable observable, Object object) { 
  Vector movies = applet.getMovieData().getMovieVector(); 
  RatingTable table = applet.getRatingTable(); 
  RatingTableModel model = (RatingTableModel)(table.getModel()); 
  // Check each movie 
  for (Iterator i = movies.iterator(); i.hasNext();) { 
   Movie movie = (Movie)(i.next()); 
   String title = movie.getTitle(); 
   // Ignore movie, if already in the table 
   if (!present(title, model.getDataVector())) { 
    // Add movie if not already in the table 
    Vector row = new Vector(); 
    row.add(title); 
    row.add(new Integer(movie.rating())); 
    row.add(new Integer(movie.getScript())); 
    row.add(new Integer(movie.getActing())); 
    row.add(new Integer(movie.getDirection())); 
    // Add new row to the table model 
    model.addRow(row); 
   } 
  } 
 } 
 // Test title to see if movie is in the data vector 
 private boolean present (String title, Vector data) { 
  // Iterate over all data elements 
  for (Iterator i = data.iterator(); i.hasNext();) { 
   // Each data element is a row vector 
   Vector v = (Vector)(i.next()); 
   // Title is first element of row vector 
   String t = (String)(v.firstElement()); 
   if (t.equals(title)) { 
    return true; 
   } 
  } 
  return false; 
 } 
}