Claude Warren created COLLECTIONS-817:
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Summary: BloomFilter: Converting Double to Int
Key: COLLECTIONS-817
URL: https://issues.apache.org/jira/browse/COLLECTIONS-817
Project: Commons Collections
Issue Type: Bug
Components: Collection
Reporter: Claude Warren
Fix For: 4.5
[https://github.com/Claudenw/commons-collections/blob/9f2945cc98747893456b73f42ab53f46a866ac37/src/main/java/org/apache/commons/collections4/bloomfilter/BloomFilter.java#L216-L251]
Should this be a double?
Since this is a pass through method that is converting a precise value from the
shape into an imprecise one I would recommend removing it. A paragraph can be
added to the class javadoc on how to estimate N and also the size of the union
and intersection with another filter. Those methods also suffer from the same
inaccuracy. If this functionality was moved to class javadoc then it is clear
to the user how to compute it and what the computation requires.
Another issue is that the argument filter's shape is not checked. The merge
should join the smaller filter into the bigger one and then the estimateN
called on the larger filter. Otherwise this method is not symmetric. One way
would be fine but the other would result in a merge error.
If this is only intended for filters with the same number of bits then the
expected result of a mismatch is not documented.
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