Re: Master Detail with JCombo & JList?

From:
Michael Rauscher <michlmann@gmx.de>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 23 Jun 2009 13:14:35 +0200
Message-ID:
<h1qder$a5s$03$1@news.t-online.com>
mttc wrote:

JComboBox as master, JList as detail. both components fill the model
from DB.
How make it work, when i change the master, the detail update list
automatically.
comment: I prepare load all records of details at once, there is few
records. but I not see on DefaultListModel any method for filter view
according the master key


Of course. There's no reason for (Default)ListModel to provide filter
methods. There are many ways to implement a filter but it depends on
interpretation, the concrete situation and the design of the
application, of course.

A simple approach could look like the following:

interface Entity {
     int getParentId();
}

class DetailsListModel extends AbstractListModel {
     private List<Entity> details;
     private List<Entity> data;
     private int filterId;

     public DetailsListModel(List<Entity> details) {
         this.details = details;
         filter();
     }

     public void setFilterId(int id) {
         this.filterId = id;
         filter();
     }

     private void filter() {
         if ( filterId == 0 )
             data = details;
         else {
             data = new ArrayList<Entity>();
             // add matching elements to data
         }
         fireContentsChanged(this, 0, data.size());
     }

     // implement abstract methods based on data
     // getSize
     // getElementAt
}

To get a reusable filter one could implement an observable filter class
that uses Comparator or bean introspection. A ListModel can then use and
observe an instance of this filter class.

Bye
Michael

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