Should I use Guava or Mug or Both?

[xingyutangyuan]

Guava and Mug are both general-purpose library. And there is also guava-mug artifact.

What are some guidelines on using either one and do I add both as my dependencies? Is there overlaps?

[fluentfuture]

That's a great question.

Within Google we use Guava like breathing air. ImmutableList, ImmutableMap are everywhere. I also frequently use Preconditions, CharMatcher, and some useful packages: com.google.common.primitives,com.google.common.io. And while not used very often, com.google.common.hash is great when I need to do hashing.

Now assuming I'm writing code outside of Google, chances are Guava is already in the dependencies anyways. But if it's not, I might need to be careful because some version of it may already exist in the transitive dependency closure and I don't want version conflicts.

Mug on the other hand is less versatile. But for what it does well, its usage has been ramping up rapidly inside Google. This includes:

• BiStream + BiCollectors - almost anyone who uses Map can take advantage of BiStream (if they like Java streams)
• Substring - Guava hasn't focused much on adding rich string manipulation utils (internally there used to be a StringUtils class with like 76 random static util methods. It was deprecated as such classes are easy to become a dumping ground)
• StringFormat - It's both a convenient parser and a template. Guava historically decided not to add string templating. But with lambda and ErrorProne compile-time checks, it turns out pleasantly useful.

The recent addition of DateTimeFormats, which you helped in the making, is also a nice utility I'd personally recommend. It saves time learning the Java date time formatting syntax and makes the time format WYSIWYG.

[xingyutangyuan]

Thanks for the guideline!

Any thoughts between Splitter and the split mehtods of Substring? Seems like both do string splitting.

[fluentfuture]

Oh yeah Substring does do lots of what Splitter does.

The bottom line: I wouldn't pull in extra Mug dependency if Splitter already works, and vice versa.

When I have both deps,I tend to use Substring (StringFormat if it's based on a compile-time format string) for almost all splitting work. I guess because Substring does more than just splitting, and it's natural to use the same abstraction for all of finding, matching, removing, splitting and replacing without switching gear.