Extracting A Value From Hashmap

[henri henri]

I have my HashMap set up to accept a film title as the key and a JavaBean encapsulating information about the film as a value. I need to get the JavaBean out of the HashMap in order to format and present the information in the JavBean. I get stuck at the following line FilmBean film = container.get(it.next());. This is because the get() method only retrives the key.

    try {
      FileInputStream file = new FileInputStream("FilmContainer.ser");
      ObjectInputStream obInputStream = new ObjectInputStream(file);
      container = (FilmContainer)obInputStream.readObject();
       NUM_FILMS = container.size();
          Set set = container.keySet();
          Iterator it = set.iterator();
          while(it.hasNext()) {
            FilmBean film =  container.get(it.next());
        
       
               String name = (String)film.getName();
               String genre = (String)film.getGenre();
               int year = (int)film.getYear();
               String year2 = String.valueOf(year);
               int length = (int)film.getLength();
               String length2 = String.valueOf(length); 
               double audio = (double)film.getAudio();
               String audio2 = String.valueOf(audio);  
               String actorname = film.getActorName(); 
              
           
               nameLabel.setText("Titre du film: " + name);
               genreLabel.setText("Cat�gorie: " + genre);
               actorLabel.setText("Acteur: " + actorname);  
               yearLabel.setText("Ann�e: " + year2);
               lengthLabel.setText("Dur�e: " + length +" Minutes");
               audioLabel.setText("Audio: " + audio2);
            
       System.out.println(name +  " | "  + genre + ",   " + actorname + ",  Ann�e: " + year2 + ",  Dur�e: " +  length2  + "  Minutes,"  + "   "  + "Audio: " + audio2);
 
         
          }
             
           System.out.println("Nombre de films:  " + NUM_FILMS);        
     } catch (Exception ioex) { }
 
 } 
  

[Seb Mathe]

I can be sure because you don't post your FilmContainer code, but wouldn't it be better with :

FilmBean film = container.get(it.next());

Note : HashMap.get(aKey) returns the object associated with the key, not the key...

And are all the cast statements ((int)film.getLength()...) necessary

[henri henri]

The FilmContainer is a simple class extended from HashMap

[henri henri]

This compiles but does not retrieve each Javabean.

 
Set set = container.keySet(); 
        Iterator it = set.iterator(); 
 
          while(it.hasNext()) {
          
      
            FilmBean film = (FilmBean)container.get(it.next());

[Ernest Friedman-Hill]

Right. It retrieves all the keys, because you're iterating over the keySet(). If you want to iterate over all the values, you can use container.values() in place of container.keySet() in the above.

You need to slow down a little, take a deep breath, and pay attention more.

[henri henri]

Thank you so much for your help Mr. Friedman-Hill. It works!! The data in my FilmBeans is printed out. It worked with this code:

     Collection values = container.values(); 
        Iterator it = values.iterator(); 
 
          while(it.hasNext()) {
          
      
            FilmBean film = (FilmBean)it.next();

[Seb Mathe]

If container is a Map,

 
Set set = container.keySet(); 
Iterator it = set.iterator(); 
while(it.hasNext()) {
    FilmBean film = (FilmBean)container.get(it.next());
}

you must retrieve values, too.