Re: [cp-patches] [RFA/JDWP] ReferenceKey

[Archie Cobbs <archie at dellroad dot org>]

Keith Seitz wrote:
> One minor snafu -- maybe someone sees a way around this.
>
> In order to facilitate the two types of needed lookups, we keep around
> the two tables I mentioned:
>
> oidTable maps from Object (ReferenceKey) to ObjectId
> idTable maps from Long (numerical ID) to ObjectId
>
> iodTable is used by the back-end and the VM parts to query IDs for
> Objects to be passed to the debugger. idTable is for looking up objects
> from commands sent by the debugger.
>
> Whatever the table type (Hashtable or WeakHashMap), I would need to keep
> a ReferenceQueue of the garbage collected Objects in order to clear the
> IDs from garbage collected Objects from idTable.
>
> Unfortunately, with the WeakHashMap, there is no way to get the keys put
> into a ReferenceQueue (that I can see at least). Consequently, I'll
> never know when to clean up the idTable unless I iterate over the table,
> asking each ID whether its object is still valid.
>
> So if I am to continue to use two tables for lookups, I need a little
> more control over the garbage collection of keys than WeakHashMap
> affords me, I think.

Seems you're right.. it sounds a bit more complicated than a simple
weak-key hash map would allow. Makes for an interesting programming
exercise then.. :-)

-Archie

__________________________________________________________________________
Archie Cobbs      *        CTO, Awarix        *      http://www.awarix.com