movielistview.java

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/*
 * MovieListView - the list View of the MovieCat model.
 *  This view implements the view of the movie list
 * Copyright (c) 2001, Bruce E. Wampler
 */

import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class MovieListView 
    extends WmvcView
    implements	ListSelectionListener	// for JList
{
    // need updating to avoid interaction between update and
    // valueChanged listener
    private static boolean updating = false;
    private JPanel listPanel;
    private JList jlist;

    private MovieModel myModel;
    private DefaultListModel movieList;

    public JPanel getPanel() { return listPanel; }

    public MovieListView()
    {
	// Build list view which is simply a JList in a JPanel
	myModel = (MovieModel)WmvcApp.getModel();
	myModel.addView(this);	// add view to model list

	movieList = new DefaultListModel(); // first allocation
	movieList.addElement("No Movie List Opened");

	listPanel = new JPanel();
	listPanel.setLayout(new BorderLayout());

	jlist = new JList(movieList);
	jlist.setSelectionMode(
			ListSelectionModel.SINGLE_SELECTION);	    
	jlist.setSelectedIndex(0);
	jlist.addListSelectionListener(this); // valueChanged

	listPanel.add(jlist,BorderLayout.CENTER);
    }

    public void updateView()
    {
	// Called when model changes
	updating = true;
	// if list changed, don't need to refresh here
        if (myModel.getListChanged())
        {
	    movieList.ensureCapacity(
	    		      myModel.getNumberOfMovies() + 8);
	    movieList.clear();

	    // See if just the selection changed
	    // copy titles from movie list to view list
            ListIterator it = myModel.getMovieListIterator();
            while (it.hasNext())
              {
		Movie m = (Movie) it.next();
		movieList.addElement(m.getTitle());
              }
        }
	// Always update selected item
	// Note that by using the DefaultListModel, these will
	// trigger valueChanged, so we need the updating value
	jlist.setSelectedIndex(myModel.getCurrentMovieIndex());
	jlist.ensureIndexIsVisible(
			       myModel.getCurrentMovieIndex());
	updating = false;
    }

    // Implement ListSelectionListener
    public void valueChanged(ListSelectionEvent e)
    {
	if (e.getValueIsAdjusting()) // Still adjusting?
	    return;

	JList theList = (JList)e.getSource();
	if (! theList.isSelectionEmpty()) 
	{
	    int index = theList.getSelectedIndex();
	    // now set the model to use the selected movie name
	    if (!updating)
		myModel.setCurrentMovieIndex(index);
	}
    }
}