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https://issues.apache.org/jira/browse/HBASE-1655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12731574#action_12731574
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Ken Weiner commented on HBASE-1655:
-----------------------------------
- Even though TreeMap uses the comparator rather than the equals method to
compare keys, using a byte[] as the key seems to break the contract of a
java.util.Map. The last paragraph of the [Map
API|http://java.sun.com/javase/6/docs/api/java/util/Map.html] says that impls
are free to avoid calling equals() but the containsKey(Object key) method
should "return true if and only if this map contains a mapping for a key k such
that (key==null ? k==null : key.equals(k))". As you mentioned, you'd need a
byte[] wrapper in order to be compliant. So a byte[] key will work in a
TreeMap (and not in a HashMap), but we'd break the Map contract. Seems better
to just use String and HashMap which works well and satisfies the Map contract.
- Allowing both the static methods and the public construction would bring me
back to the complaint I had originally with this class. :) It becomes
confusing for a user trying to quickly understand how he/she is supposed to
interact with this class. I guess this can all be explained away with
documentation, but, it doesn't feel "good".
- Also, yes, there would be a problem with re-instantiating the static map
multiple times, but this could be prevented by implementing a Singleton pattern
so that the static access operates on an internal singleton instance with a
member Map rather than a static Map.
- I agree that there is no reason to construct HBC's for each invocation. An
internal HBC instance can be constructed and reused.
- Is there a checkstyle.xml file for HBase? That would make it easy to check
my code for formatting problems before submitting patches.
> Usability improvements to HTablePool
> ------------------------------------
>
> Key: HBASE-1655
> URL: https://issues.apache.org/jira/browse/HBASE-1655
> Project: Hadoop HBase
> Issue Type: Improvement
> Components: client
> Reporter: Ken Weiner
> Assignee: Ken Weiner
> Attachments: HBASE-1655-v2-partial.patch, HBASE-1655.patch
>
>
> A discussion on the HBase user mailing list
> (http://markmail.org/thread/7leeha56ny5mwecg) led to some suggested
> improvements for the org.apache.hadoop.hbase.client.HTablePool class.
> I will be submitting a patch that contains the following changes to
> HTablePool:
> * Remove constructors that were not used.
> * Change access to remaining contstructor from public to private to enforce
> use of the static factory method getPool.
> * Change internal map from TreeMap to HashMap because I couldn't see any
> reason it needed to be sorted.
> * Remove HBaseConfiguration and tableName member variables since they aren't
> really properties of the pool itself. They are associated with the HTable
> that should get instantiated when one is requested from the pool, but not
> already there.
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