A Java collection of value pairs? (tuples?)

Question

I like how Java has a Map where you can define the types of each entry in the map, for example <String, Integer>.

What I'm looking for is a type of collection where each element in the collection is a pair of values. Each value in the pair can have its own type (like the String and Integer example above), which is defined at declaration time.

The collection will maintain its given order and will not treat one of the values as a unique key (as in a map).

Essentially I want to be able to define an ARRAY of type <String,Integer> or any other 2 types.

I realize that I can make a class with nothing but the 2 variables in it, but that seems overly verbose.

I also realize that I could use a 2D array, but because of the different types I need to use, I'd have to make them arrays of OBJECT, and then I'd have to cast all the time.

I only need to store pairs in the collection, so I only need two values per entry. Does something like this exist without going the class route? Thanks!

Answer 1

AbstractMap.SimpleEntry

Easy you are looking for this:

java.util.List<java.util.Map.Entry<String,Integer>> pairList= new java.util.ArrayList<>(); 

How can you fill it?

java.util.Map.Entry<String,Integer> pair1=new java.util.AbstractMap.SimpleEntry<>("Not Unique key1",1); java.util.Map.Entry<String,Integer> pair2=new java.util.AbstractMap.SimpleEntry<>("Not Unique key2",2); pairList.add(pair1); pairList.add(pair2); 

This simplifies to:

Entry<String,Integer> pair1=new SimpleEntry<>("Not Unique key1",1); Entry<String,Integer> pair2=new SimpleEntry<>("Not Unique key2",2); pairList.add(pair1); pairList.add(pair2); 

And, with the help of a createEntry method, can further reduce the verbosity to:

pairList.add(createEntry("Not Unique key1", 1)); pairList.add(createEntry("Not Unique key2", 2)); 

Since ArrayList isn't final, it can be subclassed to expose an of method (and the aforementioned createEntry method), resulting in the syntactically terse:

TupleList<java.util.Map.Entry<String,Integer>> pair = new TupleList<>(); pair.of("Not Unique key1", 1); pair.of("Not Unique key2", 2);