Re: Synchronization when collecting data from the EDT?

From:

Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid>

Newsgroups:

comp.lang.java.gui

Date:

Fri, 10 Jun 2011 01:25:58 +0200

Message-ID:

<isrkq4$hkf$1@dont-email.me>

On 10/06/2011 01:17, Daniele Futtorovic allegedly wrote:

static <V> V invokeAndWait( final Callable<V> callable )
    throws InterruptedException
{
    final Exchanger<V> x = new Exchanger<V>();
    EventQueue.invokeLater(
        new Runnable(){ @Override public void run() {
            try {
                x.exchange( callable.call() );
            }
            catch (InterruptedException iex ){
                Thread.currentThread().interrupt();
            }
            catch ( Exception e ){
                //exception in the callable. Blow shit up.
                throw new RuntimeException(e);
            }
        }}
    );

    return x.exchange( null );
}

Realised one big mistake: the caller might block indefinitely.

Corrected version:

static <V> V invokeAndWait( final Callable<V> callable )
    throws InterruptedException
{
    final Exchanger<V> x = new Exchanger<V>();
    EventQueue.invokeLater(
        new Runnable(){ @Override public void run() {
            try {
                x.exchange( callable.call() );
            }
            catch (InterruptedException iex ){
                //best effort
                try { x.exchange( null ); } catch ( InterruptedException
iex2 ){}
                Thread.currentThread().interrupt();
            }
            catch ( Exception e ){
                //exception in the callable. Blow shit up.
                try {
                    x.exchange( null );
                    throw new RuntimeException(e);
                }
                catch ( InterruptedException iex2 ){
                    Thread.currentThread().interrupt();
                }
            }
        }}
    );

    return x.exchange( null );
}