Nashorn: How to select constructor to invoke

Question

I know from this page that I can select a method like this:

API["test(Integer[])"](1);

How do I do this for constructors? In particular, I'm trying to instantiate a java.awt.Color from Nashorn:

var highlightColor = new java.awt.Color(1, 1, 128/255, 1);

I get the following error: Can't unambiguously select between fixed arity signatures [(float, float, float, float), (int, int, int, int)] of the method java.awt.Color. for argument types [java.lang.Integer, java.lang.Integer, java.lang.Double, java.lang.Integer]

I've tried this:

var highlightColor = new java.awt.Color["(float,float,float,float)"](1, 1, 128/255, 1);

But that gives me this error: Caused by: :52 TypeError: null is not a function

score 4 · Answer 1 · answered Dec 19 '14 at 12:51

We added this functionality, but it will only be available with Java 8u40. The exact syntax is java.awt["Color(int, int, int)"] (the signature is part of the last name component, consistent with how it works on method names). You can try it out with early access releases of 8u40 at this time (it's scheduled for release in March 2015).

Constant · Accepted Answer · 2014-12-09T22:08:45.197

2

You need to make sure you're passing in 4 integers (or floats in this case), try this.

var highlightColor = new java.awt.Color(1.0, 1.0, 128/255, 1.0);

edited Dec 09 '14 at 22:08

answered Dec 09 '14 at 21:53

Constant

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`(int) 128 / 255` is `0` – Mmmh mmh Dec 09 '14 at 22:00
Then he should pass in 4 floats, the point being that he needs to follow the proper requirements of the constructor – Constant Dec 09 '14 at 22:08
You are both right, thanks! How do I tell who had the answer first? – David Struck Dec 09 '14 at 23:32

Mmmh mmh · Answer 3 · 2014-12-09T22:09:41.607

2

Pass either 4 ints or 4 floats

var highlightColor = new java.awt.Color(255, 255, 128, 255);

OR

var highlightColor = new java.awt.Color(1.0, 1.0, 128/255, 1.0);

edited Dec 09 '14 at 22:09

answered Dec 09 '14 at 21:59

Mmmh mmh

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Nashorn: How to select constructor to invoke

3 Answers3