Requirement for _default_ eviction region

brian.stansberry Mar 12, 2008 1:19 PM

Follow-on to our discussion on http://jira.jboss.org/jira/browse/JBCACHE-1288

Looking at RegionManager for other reasons and noticed this bit in getRegion(Fqn, Region.Type, boolean):

 // test if the default region has been defined. If not, and if eviction regions
 // are in use, throw an exception since it is required.
 if ((nextBestThing == null || nextBestThing.getFqn().isRoot() && !regionsRegistry.containsKey(Fqn.ROOT))
 && type == EVICTION)
 {
 if (log.isTraceEnabled())
 log.trace("Next best region is " + nextBestThing + ". RegionsRegistry contains a default? " + regionsRegistry.containsKey(Fqn.ROOT) + " Region type requested = " + type);
 throw new RuntimeException("No default eviction region defined!");
 }

Looks like we *are* enforcing a requirement for a _default_ region.

1. Re: Requirement for _default_ eviction region

brian.stansberry Mar 12, 2008 1:32 PM (in response to brian.stansberry)
Looking at the usage of this method, only code that passes in Region.Type.EVICTION is EvictionInterceptor.canIgnoreEvent(). And that can handle a null return just fine. So, seems we could safely replace the above with:

// test if the default region has been defined. If not, and if the request // is for an eviction region, return null if ((nextBestThing != null && nextBestThing.getFqn().isRoot() && !regionsRegistry.containsKey(Fqn.ROOT)) && type == EVICTION) { log.trace("No default eviction region; returning null"); nextBestThing = null; }

Haven't looked carefully to see if the method contract implies it won't return null.
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2. Re: Requirement for _default_ eviction region

brian.stansberry Mar 12, 2008 1:34 PM (in response to brian.stansberry)

And, change the if test order so "type == EVICTION" comes first. :-)
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3. Re: Requirement for _default_ eviction region

manik Mar 12, 2008 3:36 PM (in response to brian.stansberry)

Hmm, good point. And this plays much better into what we expect with default behaviour.
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