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https://issues.apache.org/jira/browse/UIMA-5763?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16531957#comment-16531957
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Marshall Schor commented on UIMA-5763:
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There are 2 topics in this comment chain: a "no_access" and "read-only". The
original impetus was to prevent accidental "releasing" of CASes in uima-as
context while the cas was sent to a remote service.
The various expansions and augmentations in the comment chain, if implemented,
probably slightly slow down normal CAS operations.
* I wonder if it's worth checking on every FS creation or feature update,
whether or not a global (to the CAS) read-only flag is set.
* I wonder if it's worth checking on every index or feature access, whether or
not a no-access flag is set.
Doing the original request (preventing a user from accidentally releasing a
CAS) is a very low frequency operation, so no performance impact would be
expected.
For the next release, I'll make a new Jira, which will cover a minimal
implementation of the original intent (preventing accidental releasing of
CASes), and leave this Jira open, in case we figure out a good approach on
going forward with read-only / no-access that won't impact performance.
> UIMA: need a way to lock a CAS to prevent user from releasing it prematurely
> ----------------------------------------------------------------------------
>
> Key: UIMA-5763
> URL: https://issues.apache.org/jira/browse/UIMA-5763
> Project: UIMA
> Issue Type: New Feature
> Components: UIMA
> Reporter: Jerry Cwiklik
> Assignee: Marshall Schor
> Priority: Major
> Fix For: 3.0.1SDK, 2.10.3SDK
>
>
> UIMA-AS client supports an async style of sending CASes for processing to a
> remote service. When using sendCAS( CAS aCas), the code serializes CAS and
> dispatches it to the remote but keeps the CAS in a cache. When a reply comes,
> the cached CAS is used to deserialize a response. The contract is that the
> user code should not call CAS.release(). When a reply finally comes, the CAS
> is handed over to an application callback and upon return from the callback,
> the UIMA-AS releases the CAS.
> Problem: there is nothing to prevent user code to violate the contract. If
> CAS.release() is called while UIMA-AS client awaits reply (or during reply
> deserialization), bad things happen. In a specific use case, a NPE was thrown
> during deserialization and debugging was quite painful.
> Proposed solution: to protect integrity of a CAS need a way to lock/unlock
> it. Such facility can be added to CASImpl class. When a user code tries to
> call release() when a CAS is locked, the code should throw an exception
> (IllegalStateException or similar).
> WDYT?
>
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