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javaunordered-setunmodifiable

Class that describes a immutable, ordered set

I need some class/interface name that describes an immutable, ordered set (in input order, like LinkedHashSet). I can of course just use the class like this:

class Foo {
    public final Set<Long> frozenOrderedSet;

    public Foo(List<Long> input) {
        frozenOrderedSet = Collections.unmodifiableSet(new LinkedHashSet(input));
    }
}

But this would not clarify my approach. I would like to make it clear to everyone reading the source that the Set is unmodifiable and unique while maintaining it's order with for(Long l : set){}.

Solution

  • Guava's ImmutableSet provides a high-performance, immutable Set with reliable, user-specified iteration order. There are also variations like ImmutableSortedSet.