Re: Request for new feature

[Marcel Ruff <ruff at swand.lake.de>]

Matt Jensen wrote:
> 
> On Fri, 23 Feb 2001, Peter Antman wrote:
> 
> > On 23 Feb, Marcel Ruff wrote:
> > > Peter Antman wrote:
> > >>
> > >> Naively I have assumed that the following behaviour was supported...
> > >> - A new client subscriber will only get new messages, not messages
> > >>    published before it logged in and started its subscription.
> >
> > > I have added your suggestion, the new publish qos is called
> > >    <isVolatile>true</isVolatile>
> 
> For what it's worth as an idea, OpenQueue supports a value for initial
> backlog of messages.  If 0, you get just new messages since your
> subscription started.  If -1, you get all the old messages. If 5, you get
> the last 5 messages before you started.

This is a good idea!

Could you please explain, is the following statement correct:

All messages are backlogged when published, and
each subscriber can set the number of backlog messages
he wishes to receive when he subcribes?

> The motivation was for scrolling
> headline news in an applet, so you are guaranteed to see some headlines
> without waiting.  (For a demo, see http://www.newsblip.com/applet.php3)

I just tried it but with Linux/netscape 4.75 i got this error in the
Java console:


error in paint()...
java.lang.NullPointerException: trying to get field at offset 0
  at org.openqueue.applet1.OQApplet.paint(OQApplet.java:437)
  at org.openqueue.applet1.OQApplet.jbInit(OQApplet.java:135)
  at org.openqueue.applet1.OQApplet.init(OQApplet.java:89)
  at
netscape.applet.DerivedAppletFrame$InitAppletEvent.dispatch(DerivedAppletFrame.java:553)
  at
java.awt.EventDispatchThread$EventPump.dispatchEvents(EventDispatchThread.java:81)
  at java.awt.EventDispatchThread.run(EventDispatchThread.java:135)
  at
netscape.applet.DerivedAppletFrame$AppletEventDispatchThread.run(DerivedAppletFrame.java:911)
error in paint()...
java.lang.NullPointerException: trying to get field at offset 0
  at org.openqueue.applet1.OQApplet.paint(OQApplet.java:437)
  at org.openqueue.applet1.OQApplet.jbInit(OQApplet.java:135)
  at org.openqueue.applet1.OQApplet.init(OQApplet.java:89)
  at
netscape.applet.DerivedAppletFrame$InitAppletEvent.dispatch(DerivedAppletFrame.java:553)
  at
java.awt.EventDispatchThread$EventPump.dispatchEvents(EventDispatchThread.java:81)
  at java.awt.EventDispatchThread.run(EventDispatchThread.java:135)
  at
netscape.applet.DerivedAppletFrame$AppletEventDispatchThread.run(DerivedAppletFrame.java:911)


any idea?

regards,

Marcel

-- 
Marcel Ruff
mailto:ruff at swand.lake.de
http://www.lake.de/home/lake/swand/
http://www.xmlBlaster.org