Re: using threads

From:

"Daniel Pitts" <googlegroupie@coloraura.com>

Newsgroups:

comp.lang.java.programmer

Date:

29 Dec 2006 23:28:33 -0800

Message-ID:

<1167463713.595297.128620@n51g2000cwc.googlegroups.com>

Brandon McCombs wrote:

hello,

I have an LDAP program that uses threads to perform LDAP searches.
After actually getting the threads to properly start [I was calling
run() instead of "new Thread(p).start()"] my application responds really
fast and keeps chugging while the query in the background completes. The
problem is that I don't know how to actually retrieve the results from
the Vector that they were placed in so that I can display them in the
JList that I created. Since my program continued on, the code goes past
the point where the Vector normally would have data (without threads)
and would get loaded into the Jlist. So what's the proper way to
backtrack to get my Vector only after the thread has finished so the
data can be viewed? Do I have to end up employing another thread to
monitor the first one and then the code I have that loads the Vector
into my JList would get put into the second thread to be executed when
it detects the first thread completed?

thanks

something like this:

public class MyWorker implements Runnable {
    // fields and constructor
    public void run() {
        final Result result = doWork();
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                addResultToList(result);
            }
        });
    }
}

You may have to move some things around in your program, Since you are
using threads, you need some sort of callback mechanism (such as the
addResultToList method, as I called it here). Its important to use
invokeLater, so that any GUI manipulation happens on the Event Dispatch
Thread. (google Swing and Threads)
Also look up SwingWorker. It wasn't a part of the standard Java
distribution, but you can find a copy of it easily online.