Optimize ImmutableCollection builders

[Louis Wasserman, 2012-05-19 15:45:02]

The goal is to eliminate gratuitous copying from ImmutableCollection builders.

In particular, ImmutableSet.Builder stores an explicit Object[] internally,
which is deduped *in place* and used without any copying whatsoever if

a) the builder was initialized to exactly the right size (this will pay off more
as we expose initial builder capacity controls, and use it more internally)
b) no dups were found, so the entire Object[] consists of unique elements

Most of the payoff will come down the line with the compact collections rewrite.

[Chris Povirk, 2012-05-23 21:20:04]

Too-quick review before leaving for the airport.

http://codereview.appspot.com/6210074/diff/3001/guava/src/com/google/common/c...
File guava/src/com/google/common/collect/ImmutableSortedSet.java (right):

http://codereview.appspot.com/6210074/diff/3001/guava/src/com/google/common/c...
guava/src/com/google/common/collect/ImmutableSortedSet.java:593: return
construct(comparator, size, contentsArray);
Do we need to update |size| here, as in ImmutableSet?  If so, we should have
tests to prove it.

[Louis Wasserman, 2012-05-25 15:25:46]

http://codereview.appspot.com/6210074/diff/3001/guava/src/com/google/common/c...
File guava/src/com/google/common/collect/ImmutableSortedSet.java (right):

http://codereview.appspot.com/6210074/diff/3001/guava/src/com/google/common/c...
guava/src/com/google/common/collect/ImmutableSortedSet.java:593: return
construct(comparator, size, contentsArray);
On 2012/05/23 21:20:04, Chris Povirk wrote:
> Do we need to update |size| here, as in ImmutableSet?  If so, we should have
> tests to prove it.

Done.

[Chris Povirk, 2012-05-25 20:27:21]

LGTM

[Louis Wasserman, 2012-05-25 20:32:48]

On 2012/05/25 20:27:21, Chris Povirk wrote:
> LGTM

The CL is at
http://code.google.com/r/wassermanlouis-guava/source/detail?r=ecd1b1715812b90...
.

[Chris Povirk, 2012-05-31 19:10:08]

Somehow this made some reflect+testing tests flaky(!).  I was looking in
completely the wrong place to fix them: The bug is actually in TypeToken, and I
have a fix.  This CL will go in after it.