On 10/29/2015 02:35 AM, Pavel Rappo wrote: > While working with an API that extensively uses java.lang.CharSequence, I've > noticed most JDK implementations of CharSequence do not optimize for corner > cases in CharSequence.subSequence(int start, int end). Namely, > > 1. start == end (an empty subsequence)
Yeah, returning a canonical "empty" sequence in this case is probably okay. But, I have doubts about it, because you'd want to match the exact implementation type, to keep the type profiles happy. > 2. start == 0 && end == CharSequence.this.length() (the same sequence) Nope. Doesn't that break when CharSequence implementation is mutable? E.g. with StringBuilder, you cannot return "this" when "end == StringBuilder.length()" at the time of .subSequence() call. Thanks, -Aleksey
