Details
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Bug
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Status: Closed
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Major
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Resolution: Won't Fix
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2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.0.5, 2.0.6, 2.0.7, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.2.0, 2.2.1
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None
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Description
CachingLocaleUrlDefinitionDAO#refreshRequired() can incorrectly return false in certain circumstances, causing refresh to not update Tile definitions even though one or more underlying definition XML files have been updated on the file system since startup/last refresh.
Tiles stores an in-memory cache of Tile definitions keyed by locale. These definitions are built lazily as requests come in, based on the locale of the request. If the locale on the request doesn't yet have definitions associated with it, definitions are built for that locale (and parent locales) on-the-fly and cached. If the lazy building of definitions for a new locale results in an updated XML file loaded from the file system that is shared by an existing locale, the definitions already cached for other locales that share the same definition file should be invalidated.
Use Case:
- Updated Tile definition XML files are pushed onto servers. The servers continue to field requests.
- A request with a previously unseen locale comes in, causing a set of definitions to be built for that locale and parent locales. The updated XMLs are processed from the file system for the new locale only, which updates the global cache of XML file last modified dates (BaseLocaleUrlDefinitionDAO#lastModifiedDates)
- BaseLocaleUrlDefinitionDAO#refreshRequired() compares file system last modified dates to the cached ones and returns true if they differ. Since the global cache of last modified dates was updated in the previous step, the framework doesn't detect that anything has changed. Thus, it still holds out-dated definitions for all locales other than new ones that come in after the XML file push.
I don't have test case, unfortunately, but my steps to reproduce using a Servlet environment and ResolvingLocaleUrlDefinitionDAO are:
- Use a Tile definition XML files with no locale suffix, e.g. "my-base-tile-defs.xml"
- Issue a request with the "Accept-Language" HTTP header "en-us". Tile definitions are built for locales "en-us", "en" and "" all using the same base XML file
- Update one of the tile definitions in the XML, save to the file system
- Issue a request with the "Accept-Language" HTTP header "fr-fr". Tile definitions are built for locales "fr-fr", "fr" and rebuilt for "" all using the updated XML file. Cached definitions for "en-us" and "en" are not invalidated, even though the underlying XML file used to build both of them are now changed. This is because BaseLocaleUrlDefinitionDAO#lastModifiedDates now has the updated last mod date found when the definitions were built for "fr-fr", even though the updated definitions are not reflected in the definitions for "en-us"