Question

I need a java dictionary that would be like (C# representation):

Dictionary<SomeEnumType, List<int, long>>

So I want to use it like this:

List<int, long> v1 = myDic[SomeEnumType.Value1];

foreach(int i in v1)
{
    long l1 = v1[i];
}

And the List should be unique based on the int value.

What java structure supports the above?

Answer 1

You would use something like this:

HashMap<SomeEnumType, HashMap<Integer, Long>>

You would not want to use List because it stores single items whereas you want a collection of key-value pairs or mappings. A HashMap will only store objects for unique keys. In this case, the inner HashMap will store only unique integers and the outer HashMap will store only unique Enum types. You can look at the different available implementations of Map to see which one will best suit your needs.

Reference: http://docs.oracle.com/javase/7/docs/api/java/util/Map.html