About the stream deduping method (original) (raw)

Kevin Bourrillion kevinb at google.com
Thu Jan 24 12:16:22 PST 2013

Brian's survey summary:

"distinct" seemed preferred to "unique".

Sounds good, let this be the end of "unique" then.

Also, most other method names are verby; I propose changing to "removeDuplicates" or "filterDuplicates".

About the term "duplicate". If it were always the case that the first occurrence of 'obj' in a stream is the one preserved, and all the rest thereby deemed to be the "duplicates" and excluded, then there would be a stronger reason to like the use of "duplicates" here. Since that's not the case, it's just "meh".

About "remove". It sounds very mutative. Since Streams feel similar to Iterators, there is some potential for confusion.

About "filter". The sense is inverted. filter() preserves the ones that * do* match the predicate. This would have to be something like "filterOutDuplicates" (yuck).

About consistency. Right now among the chaining-style methods you've got imperative verbs (filter, map, limit, explode, perhaps sort), you've got nouns (substream), adjectives (parallel, sequential, sorted), and one that's not even based in anything grammatical (tee). (Side point: the set of terminal operations are no more consistent than this, either.) If consistency seems at all attainable (?), we would have to start by choosing which out of all this we want to be consistent with.

*If I had to choose. *I would probably just go with: distinct(). That's all SQL needed, and I think it did fine with it.

-- Kevin Bourrillion | Java Librarian | Google, Inc. | kevinb at google.com

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