Java combination of Set and List interfaces

Question

I have a data structure, for which I am currently using an ArrayList. I realised that in this structure I do not want any duplicates to be present. My first thought was to use some form of set, however the order is also important. After a bit of googling and searching the Collections docs I found LinkedHashSet which almost does the job. Unfortunately, one of the primary reasons for preserving order is because I am using the get(int index) method of the ArrayList for random access, and I can't see any way around this.

More concisely - I need a set that preserves order and allows random access. None of the classes I have so far looked at provide this functionality. Does anyone know of a class that offers this, or will I have to make it myself? If it is the latter case are there any pitfalls when creating such a structure that people are aware of?

(Alternatively, a quick and easy way of checking for and removing duplicates form an ArrayList or similar structure would suffice)

EDIT: for clarity, it is the order that elements are added to the list that is important, not how they compare to one another

Answer 1

SetUniqueList from commons-collections:

List<Foo> uniqueList = SetUniqueList.decorate(new ArrayList<Foo>());

(unfortunately, commons-collections still doesn't support generics, so you'll have to suppress a warning here)