Reflection: negative caching would be beneficial in redeployment scenarios
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Key: OPENJPA-219
URL: https://issues.apache.org/jira/browse/OPENJPA-219
Project: OpenJPA
Issue Type: Bug
Components: kernel
Affects Versions: 0.9.6, 0.9.0, 0.9.7
Reporter: Patrick Linskey
Fix For: 0.9.8
In a variety of situations, OpenJPA searches class hierarchies for fields.
These searches invoke Class.getDeclaredField() in order to find non-public
fields. This method throws an exception when it fails to find the specified
field, and the exception creation is, as ever, slow.
It would be useful to create a static (and thus per-classloader)
Map<WeakReference<Class>,Collection<String>> of fields known not to be
available in a given class.
It may also be beneficial to maintain a cache of which fields *are* present in
a given class, but this issue is being filed as a result of a demonstrated
performance hit during deployment due to the lack of a negative cache. If we
obtain quantitative data indicating that a positive cache would be useful, we
might want to implement such a thing at that time.
Trace 3 (2115 occurances): [excepti][00090] java/lang/NoSuchFieldException:
domainName
at
java/lang/Class.getDeclaredField(Ljava/lang/String;I)Ljava/lang/reflect/Field;(Unknown
Source)
at
org/apache/openjpa/enhance/Reflection.findField(Ljava/lang/Class;Ljava/lang/String;Z)Ljava/lang/reflect/Field;(Reflection.java:101)
at
org/apache/openjpa/util/ApplicationIds.toPKValues(Ljava/lang/Object;Lorg/apache/openjpa/meta/ClassMetaData;)[Ljava/lang/Object;
(ApplicationIds.java:89)
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