On Jun 21, 5:08 pm, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:
[...]

[...]

Right, in my GUI:

guestJList.setModel(BedAndBreakfast.getInstance().listModel);
//BedAndBreakfast is the "database"

and then in BedAndBreakfast:

  /*@see GUI
   *this method makes the DefaultListModel match the
   *HashMap which stores the data.
   *ideally, this method shouldn't be required.
   *I'm not quite sure why, but without it
   *nothing synchronizes with the JList.setModel
   *in the GUI*/
  public void sync()
  {
     listModel.clear();
     Collection<?> foos = getGuests();
     for (Object obj : foos)
     {listModel.addElement(obj);}
  }

to try to "sync" up the Map with the ListModel because every example I
see imbeds the data in with the JList, which is what I think I'm going
to do.

Sending an Array or Vector from the "database" (BedAndBreakfast) just
has no effect on syncing with the JList.

For what it's work, here's the "database":

package a00720398.data;

import java.util.*;
import javax.swing.*;
import a00720398.util.*;

public class BedAndBreakfast
{

  private static final BedAndBreakfast INSTANCE = new
BedAndBreakfast();

  private HashMap guests = new LinkedHashMap<Integer, Guest>();
  public DefaultListModel listModel = new DefaultListModel();

  private BedAndBreakfast()
  {sync();}

  public static BedAndBreakfast getInstance()
  {return INSTANCE;}

  /*@see GUI
   *this method makes the DefaultListModel match the
   *HashMap which stores the data.
   *ideally, this method shouldn't be required.
   *I'm not quite sure why, but without it
   *nothing synchronizes with the JList.setModel
   *in the GUI*/
  public void sync()
  {
     listModel.clear();
     Collection<?> foos = getGuests();
     for (Object obj : foos)
     {listModel.addElement(obj);}
  }

  public Collection<?> getGuests()
  {
     return guests.values();
  }

  public void removeGuest(int i)
  {
     System.out.println("index:  " + i);
     guests.remove(i);
     sync();
  }

  @SuppressWarnings( "unchecked" )
  public void addGuest(Guest guest)
  {
     sync();
     if (guest.getID() == 0)
     {  //if ID is default value
    int i = getGuests().size() + 1;
    guest.setID(i);  //kludge to append to the "end" of the Map
     }

     guests.put(guest.getID(), guest);  //hopefully no duplicates
     sync();
     //System.out.println("\n************\n" + getGuests());
  }
}

When I have the JList.setModel method convert the Map to Array it
simply fails to sync :(

thanks,

Thufir

Whether it was a HashMap or anything else, I just couldn't sync it with
the JList.  I ended up with the following kludge:

private DefaultListModel defaultListModel = fixModel();

guestList.setModel(defaultListModel);

  private DefaultListModel fixModel()
  {
     DefaultListModel dlm = new DefaultListModel();
     Object[] guests = BedAndBreakfast.getInstance().getGuests().toArray
();
     for (Object obj : guests)
     {
    dlm.addElement(obj);
     }
     return dlm;
  }

Which is the only way I've ever seen it done.  I know that it's possible
to sync with, for example, a HashMap or Collection in the "database",
BedAndBreakfast, but my attempts failed :(

-Thufir