[RFC][plugin]: fix concurrency problems in PAV.java

[Dr Andrew John Hughes]

On 09:45 Thu 14 Apr     , Denis Lila wrote:
> > Instead of doing this, it would be easier to change the type of
> > appletPanels to Vector<AppletViewerPanel> , then the casting is not
> > needed as AVP inherits from AP.
> 
> The casting to AppletViewerPanel is not caused by appletPanels. It
> is caused by the "panel" member. It used to be declared as an AVP,
> then I changed it to a NetxPanel, which made the 3 new casts
> necessary (but it eliminated many more casts than it added).
> 
> That said, I wouldn't mind changing the type of appletPanels
> to Vector<AVP>. Do you still think I should?
> 

Does it only ever store AVPs?  And, most importantly, are there casts
which assume AVPs are stored there?

If only the former is true, it would strengthen the type requirements
of the collection to a specific subtype so you must be sure that's
what you want and that you don't ever want to store a different subtype
or instances of the more general type.

> Thank you,
> Denis.
> 
> ----- Original Message -----
> > * Denis Lila <dlila at redhat.com> [2011-04-13 15:10]:
> > > > If a patch akin to
> > > > http://hg.openjdk.java.net/jdk6/jdk6/langtools/rev/5c2858bccb3f
> > > > goes in, I will not be responsible for my actions.
> > >
> > > I definitely don't want that ;-).
> > >
> > > Attached is the second patch. It's mostly cleanup, and it
> > > also uses "pav" in destroyApplet, instead of calling
> > > get(id) again and again.
> > >
> > > Ok to push?
> > >
> > 
> > ...
> > ...
> > 
> > <snip>
> > >
> > >              PluginDebug.debug("getCachedImageRef() getting img from
> > >              URL = ", url);
> > > @@ -910,8 +815,8 @@
> > >          SocketPermission panelSp =
> > >                  new SocketPermission(panel.getCodeBase().getHost(),
> > >                  "connect");
> > >          synchronized(appletPanels) {
> > > - for (Enumeration e = appletPanels.elements();
> > > e.hasMoreElements();) {
> > > - AppletPanel p = (AppletPanel) e.nextElement();
> > > + for (Enumeration<AppletPanel> e = appletPanels.elements();
> > > e.hasMoreElements();) {
> > > + AppletPanel p = e.nextElement();
> > >                  String param = p.getParameter("name");
> > >                  if (param != null) {
> > >                      param = param.toLowerCase();
> > > @@ -1591,15 +1496,15 @@
> > >           * at the same time.
> > >           */
> > >          try {
> > > - panel.joinAppletThread();
> > > - panel.release();
> > > + ((AppletViewerPanel)panel).joinAppletThread();
> > > + ((AppletViewerPanel)panel).release();
> > >          } catch (InterruptedException e) {
> > >              return; // abort the reload
> > >          }
> > >
> > >          AccessController.doPrivileged(new PrivilegedAction<Void>()
> > >          {
> > >              public Void run() {
> > > - panel.createAppletThread();
> > > + ((AppletViewerPanel)panel).createAppletThread();
> > >                  return null;
> > >              }
> > 
> > 
> 

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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