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https://issues.apache.org/jira/browse/LUCENENET-292?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12781008#action_12781008
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Nicholas Paldino commented on LUCENENET-292:
--------------------------------------------
It is necessary as it addresses a bug in EquitableList<T> concerning the
AddRange method and correctly setting the Capacity.
It also implements the IClonable interface, which is needed in other places
where EquitableList<T> would be used in place for ArrayList to keep the Java
and .NET more closely synchronized.
The optimization is what originally drove the issue, but caused these other
things to be addressed.
And given that Lucene .NET shares the performance concerns of Lucene, and an
optimization like this would definitely have an impact in places where it is
used (where sequences have to be compared), one could argue it's necessary,
especially if the lists being compared are both large and do not have the same
number of items.
In summary, I think that points #1 and #2 make it necessary without question,
while #3 is a more subjective decision, but still a strong argument for
inclusion none the less (Michael indicated his favor for such when this
optimization was mentioned in LUCENENET 284).
> Optimization of EquatableList<T>
> --------------------------------
>
> Key: LUCENENET-292
> URL: https://issues.apache.org/jira/browse/LUCENENET-292
> Project: Lucene.Net
> Issue Type: Improvement
> Reporter: Nicholas Paldino
> Priority: Minor
> Attachments: EquatableList3.patch, SupportClass.patch
>
>
> When comparing two IEnumerable<T> implementations, a shortcut can be taken to
> check to see if both IEnumerable<T> expose operations which returns a count
> of items (sequences cannot be equal if the number of elements in the
> sequences are not equal).
> Typically, in .NET, this is expressed through the implementation of the
> ICollection or ICollection<T> interface.
> Before enumerating through each element and comparing the two for equality,
> if the counts are accessible, they should be compared to see if the number of
> elements in the two sequences are equal. If a comparison is able to be made
> before enumerating, it will be much more performant for comparisons of
> sequences where each is ~N, but both are not equal to N, and N is very large.
> Patch to follow.
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