Consider fastutil instead of gnu trove

[benmccann]

Trove is licensed under the LGPL, which isn't compatible with the Apache 2 license that Morpheus uses. Might not be a problem for all users, but some may wish to exclude Trove from their projects due to the license.

Trove has been around for a while, but it isn't as actively developed anymore. FastUtil is much more recent, and actively developed.

Fastutil also performs much better according to http://java-performance.info/hashmap-overview-jdk-fastutil-goldman-sachs-hppc-koloboke-trove-january-2015/

[benmccann]

There's a branch which shows roughly the work required below. The code compiles, but five tests fail, so it would need to be fixed before it could be committed.

https://github.com/benmccann/morpheus-core/commits/fastutil

[Zavster]

Thanks for doing this Ben. I have made some changes to fix the tests, and also ensured that all calls to fastutil use the non-boxed and non-deprecated methods. I pushed the changes to my fork on a branch called fastutil_2 located below. Try fetch that branch and confirm all the tests pass for you, and if so, raise a PR and I'll merge it. Thanks again!

https://github.com/Zavster/morpheus-core/tree/fastutil_2

Cheers,
Zav

[benmccann]

Thanks! Probably easier for you to create the PR since you already have it pushed to GitHub.

I see you have this in a few places:

final int capacity = limit < it.unimi.dsi.fastutil.Arrays.MAX_ARRAY_SIZE ? limit : 1000;

Maybe better to change it to something like the below?

if (limit > it.unimi.dsi.fastutil.Arrays.MAX_ARRAY_SIZE) {
    throw new IllegalArgumentException("Specified limit " + limit + " is greater than max limit " + it.unimi.dsi.fastutil.Arrays.MAX_ARRAY_SIZE);
}

Or at least log a warning or something so that it doesn't just magically do something different than the user is expecting