Are there any CF-->Java gurus here? I have what "seems" like a simple project, take the java example here (the simplest demo function), and port it to CF: https://github.com/nayuki/QR-Code-generator/blob/master/java/QrCodeGeneratorDemo.java#L35. I'm looking at the doBasicDemo(). While I do have a use for the QR code generation, I'm more interested on how to have CF speak Java.

What specific questions do you have?

Let's start simple:

String text = "Hello, world!";          // User-supplied Unicode text

This declares a variable "text" that is of type String. Since CF is a typeless language, the type of the variable does not matter. So that line can be translated to CFML as:

var text = "Hello, world!";

Let's take a look at the next line:

QrCode.Ecc errCorLvl = QrCode.Ecc.LOW;  // Error correction level

Once again, the type (e.g. QrCode.Ecc) is irrelevant to CFML, so ignore it on our CFML code. The

QrCode

is a reference to the

io.nayuki.qrcodegen.QrCode

class defined in one of the

import

statements. So this line can be translated to something like:

# this emulates the "import" line
var QrCode = createObject("java", "io.nayuki.qrcodegen.QrCode");
# now we can use our imported class
var errCorLvl = QrCode.Ecc.LOW;

Now, let's move to a line with a constructor:

File svgFile = new File("hello-world-QR.svg");

Once again, we can ignore the type declaration. So now do we emulate the constructor? CFML uses the same pattern as components to pass in the constructor arguments, so that line can be translated to:

var svgFile = createObject("java", "java.io.File").init("hello-world-QR.png");

That should be enough to get you started...

QrCode.Ecc

is a nested class so I don't think your

errCorLvl

assignment will work... I can't remember how CFML handles nested classes but it need:

var QrCodeEcc = createObject("java", "io.nayuki.qrcodegen.QrCode$Ecc");
var errCorLvl = QrCodeEcc.LOW;

(different languages handle interop with nested classes differently but most use

Outer$Inner

as the reference)

That is the nitty-gritty details I was looking for. I've had spotty results in the past converting a chunk of java code like this. I'll give it a try...

It's a static method -- off the class -- so no constructor is needed.

FYI there is a guide on cfdocs https://cfdocs.org/java which covers some of the common conversion scenarios

Thank you. Proceeding forward...

BufferedImage.TYPE_INT_RGB

indicates a static field in a class, not a nested class. you can tell from the context of the Java code (or the docs)