java: represent arrays as UnmodifiableList

[RomainMuller]

🚀 Feature Request

Affected Languages

• TypeScript or Javascript
• Python
• Java
• .NET (C#, F#, ...)

Description

Since the JSII kernel currently doesn't support ways to propagate array mutations through the language border, and that the List API in Java is quite large, using immutable collections would be safer from Java's standpoint as it makes no unmet guarantees to the user.

[McDoit]

I assume the same would also be applied to dotnet?

With https://devblogs.microsoft.com/dotnet/immutable-collections-ready-for-prime-time/ maybe?

[RomainMuller]

That'd be nice. @assyadh any opinion?

[assyadh]

That'd be nice. @assyadh any opinion?

It is doable, but there is no constructor associated with ImmutableList.
Customers need to retrieve the list by calling ImmutableList.Empty
Then adding their values. Feels tedious to me:

    class Test
    {
        public ImmutableList<string> MyProperty { get; set; }
    }


     class Program
    {
        static void Main(string[] args)
        {
            // First way of doing it
            var values = new List<string> { "first", "second" };
            var list = ImmutableList<string>.Empty;
            list = list.AddRange(values);
            var test = new Test()
            {
                MyProperty = list
            };

            // Inline initialization
            var test2 = new Test()
            {
                MyProperty = ImmutableList<string>.Empty.AddRange(values)
            };
        }
    }