Comments on: Preconditions, Multimaps and partitioning with Google Collections (part 4)

By: Computing Map on Google Collections « firdau.si

Computing Map on Google Collections « firdau.si — Mon, 05 Jul 2010 13:13:24 +0000

[...] Preconditions, MultiMaps, and Partitioning with Google Collections [...]

By: Ralph’s Blog » Blog Archive » Google Guava Teil 3: Objects/StringUtils/Primitives

Sun, 06 Jun 2010 18:02:27 +0000

[...] Beautiful code with Google Collections, Guava and static imports – Part 1! Diving into the Google Guava library (part 2) Functional Java, Filtering and Ordering with Google Collections (part 3) Preconditions, Multimaps and partitioning with Google Collections (part 4) [...]

By: Computing Map on Google Collections | satukubik

Computing Map on Google Collections | satukubik — Fri, 13 Nov 2009 21:36:50 +0000

[...] Preconditions, MultiMaps, and Partitioning with Google Collections [...]

By: Aleksander Stensby

Aleksander Stensby — Fri, 06 Nov 2009 07:08:09 +0000

@fdse: Hi! Yes, Its my own, but it’s just a wrapper for the Google Collection ImmutableMap.of() method. Simply because there is also an ImmutableList.of() method, and I like static imports – there will be a problem:)

By: fdse

fdse — Fri, 06 Nov 2009 00:23:24 +0000

i dont see mapOf method in goog-collectns….is it your own method

By: Aleksander Stensby

Aleksander Stensby — Thu, 05 Nov 2009 19:00:09 +0000

Thanks Kevin! And thanks for all the effort you guys have put into these wonderful life-savers for us average-joes;)

Thanks for pointing out the specifics of MapDifference and the changes you’ve made to SetView:) I’ll be sure to check that out! With regards to string specifiers thats clearly stated in the JavaDoc, but I forgot to mention that in the blog post. Stay tuned for our article on Exceptions and validation (soon) where we explain the approach we have been using for this.

Cheers!
- Aleks

By: Kevin B

Kevin B — Thu, 05 Nov 2009 18:41:08 +0000

Thanks again for this great series!

A few things..

One, for 1.0-final I’ve added to the SetView javadoc this:

“There is usually no reason to retain a reference of type SetView; typically, you either use it as a plain Set, or immediately invoke immutableCopy() or copyInto(S) and forget the SetView itself.”

We really never intended to see “SetView union = …” in user code; it’s meant to be just a means to an end.

Not that it is _harmful_. You’re safe to use it.

The only issue with “Similarly, MapDifference…” is that MapDifference is a little bit different: it’s NOT a view. It does not update as the backing maps do. It copies data at the time Maps.difference() is invoked.

Re: Preconditions, be warned that ONLY %s is supported, not any of the other String.format() specifiers. (Sorry.)

Nothing incorrect in here though, of course! Thanks again!