https://openjdk.markmail.org/search/?q=8143850#query:8143850%20list%3Anet.java.openjdk.core-libs-dev+page:1+state:facets
On Sat, Jun 30, 2018 at 12:53 PM, Jonas Konrad <m...@yawk.at> wrote: > Hey, > > The introduction of ArrayDeque in Java 1.6 has basically replaced > LinkedList as the "default" implementation of java.util.Queue, which is > probably for the best. However, from time to time, I still see use cases > where a class that implements both Deque and List is wanted for ease of > use. LinkedList is currently the only class that supports this. One example > would be sorting the queue in-place. > > Has there been any discussion on having ArrayDeque implement List? > > There is no *technical* reason against doing so - the internal structure > of ArrayDeque is fully capable of supporting an implementation of List, and > there would be no additional fields needed that would change current memory > behavior. The existing Deque interface would also remain unaffected. > > I see two possible reasons against doing this: > > - Added maintenance effort, a lot of it duplicated from ArrayList. This > *could* be done gradually: ArrayDeque only extends AbstractCollection right > now so implementations for e.g. subList could be inherited from > AbstractList. Performance tweaking would be nice in many places though. > - Design - conceptually, a Deque is something very different from a List. > LinkedList implementing both could be seen as a mistake from that point of > view. When coding to interfaces, which is good practice anyway, this change > isn't visible though. > > Thoughts? > > - Jonas Konrad >
