How to pass values to a function with LinkedList inline?

Question

I have a simple function like:

private void function(LinkedList<String> a, LinkedList<String> b)

We already know that if those arguments were only string, passing values inline would be easy, like:

function("aaa", "bbb")

But is there a way to pass inline a LinkedList?

I tried with:

function(["A", "B", "C"], ["A", "B"])

but it does not work.

Answer 1

Change the type from LinkedList to the List interface, and then you can use Arrays.asList(T...) like

function(Arrays.asList("A", "B", "C"), Arrays.asList("A", "B"))

Answer 2

There are ways to do it, but I'm not sure they will be clearer/shorter than the non-inline ways.

For example, using Stream API :

function (Stream.of("A","B","C").collect(Collectors.toCollection(LinkedList::new)),
          Stream.of("A","B").collect(Collectors.toCollection(LinkedList::new)));

You could use Array.asList if you don't need a specific List implementation (such as LinkedList) and don't mind the resulting List being fixed sized.

Or you can use Array.asList and still get a LinkedList :

function(new LinkedList<String>(Arrays.asList("A", "B", "C")), 
         new LinkedList<String>(Arrays.asList("A", "B")));

Answer 3

There is a way, without using any framework, but spoiler alert, it does not look any good to me:

function((LinkedList<String>) Arrays.asList("A", "B", "C"),
        (LinkedList<String>) Arrays.asList("A", "B"));

If you are using the LinkedList just to concatenate the strings, then you could use StringBuilder, that could do the job and looks much better:

public void doSomething() {
    function(new StringBuilder()
            .append("A")
            .append("B")
            .append("C"), 
        new StringBuilder()
            .append("A")
            .append("B"));
}

private void function(StringBuilder a, StringBuilder b) { ... }

Cheer, Nikolas