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https://issues.apache.org/jira/browse/NIFI-988?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14936771#comment-14936771
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ASF GitHub Bot commented on NIFI-988:
-------------------------------------
Github user markap14 commented on the pull request:
https://github.com/apache/nifi/pull/92#issuecomment-144378199
@joemeszaros the concern that I have with the notion of the
ExtendedDistributedMapCacheClient is that once that is released, it will have
the same caveats as the DistributedMapCacheClient - others can extend it, so we
cannot change the interface in a non-backward-compatible way once we release it.
I think if there are specific methods that we think will be added, then we
need to implement those before we release the service. Otherwise, in order to
add new methods to the ExtendedDistributedMapCacheClient we would need to
create yet another interface that extends that one. This is all done because we
consider the Standard Services API to be "public interfaces" so that once they
are out there, we have no idea who has implemented them. As a result, if we
change them, even if we update all of the code in Apache NiFi, we may be
breaking someone else's "private" implementation.
In theory, though, this will become a lot less painful once we move to
1.0.0 because I believe the intent is to move to Java 8, which means that we
can include default implementations in the interfaces. As a result, we could
potentially add new methods to interfaces as long as they can be implemented
using existing methods.
> PutDistributedMapCache processor
> --------------------------------
>
> Key: NIFI-988
> URL: https://issues.apache.org/jira/browse/NIFI-988
> Project: Apache NiFi
> Issue Type: New Feature
> Components: Core Framework
> Reporter: Joe Mészáros
> Priority: Minor
> Labels: cache, distributed, feature, new, put
>
> There is a standard controller service, called DistributedMapCacheServer,
> which provides a distributed cache, and an associated
> DistributedMapCacheClientService to interact with the cache. But there is not
> any standard processor, which puts data into the cache, and helps the user to
> leverage the distributed cache capabilities.
> The purpose of PutDistributedMapCache is very similar to the egress
> processors: it gets the content of a FlowFile and puts it to a distributed
> map cache, using a cache key computed from FlowFile attributes. If the cache
> already contains the entry and the cache update strategy is 'keep original'
> the entry is not replaced.
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