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I’m trying to find an implementation of java.util.List and java.util.Set at the same time in Java. I want this class to allow only unique elements (as Set) and preserve their order (like List). Does it exist in JDK 6?
It’s important to have List<T>#add(int, T) so I can insert into a specific position.
TreeSetis sorted by element order;LinkedHashSetretains insertion order. Hopefully one of those is what you were after.You’ve specified that you want to be able to insert at an arbitrary location, I suspect you’ll have to write your own – just create a class containing a
HashSet<T>and anArrayList<T>; when adding an item, check whether or not it’s in the set before adding it to the list.Alternatively Apache’s commons-collections4 offers
ListOrderedSetandSetUniqueList, which behave similarly and should meet the given requirements.