IssueTracker

Some option ideas:

• AdapterCombiner
• CombinedAdapter
• CombiningAdapter
• AdapterMerger
• SequentialAdapter
• AdapterSequence
• ChainAdapter
• AdapterChainer
• AdapterChain

I kind of like ConcatenationAdapter. Though honestly, I wonder if every name is going to be initially confusing to readers, and ultimately MergeAdapter might still be best.

I think Concat / Concatenation is by far the clearest. MergeAdapter makes my mind go immediately to merge sort, which is not what this adapter does.

I personally think the name MergeAdapter is fine. My team created this exact abstraction years ago, and independently named that class "MergeAdapter". Though obviously since I have already made this connection for years; I am bias.

The fact that "MergeAdapter" reminds us of "MergeSort" reminds of "interleaving behavior" is quite a few mental hops. I think we'd all be better off by trying to disassociate that, and instead treat all words by their actual definition.

The bad part about naming this something much more specific like "ConcatenationAdapter", is that those definitions are a bit narrowly scoped. A nice thing you can accomplish with the "MergeAdapter" API is you can add and remove adapters in the middle of the list dynamically to render "collapsible" and "expandable" items or lists. I don't think the term "concatenate" captures this behavior very well, but I do think the word "merge" is broad enough to convey this.

Years ago the term MergeAdapter was common for ListViews, but that was before other APIs like RxJava and Flow entered the common Android development lexicon and brought along much more precise definitions of these terms. These APIs build very strong distinctions between interleave (merge) and strict ordered sequence of groups (concat) and we benefit from consistency with the more contemporary usage here, especially when these APIs are often used in close proximity to one another.

Normally we try to encourage spelling out terms in API rather than abbreviating, but concat is a special case here. String, Rx and others standardized on concat so long ago that many people aren't even familiar with the fully expanded term; better to be consistent with the ecosystem here.