Example of coding a `struct` in Java when packaging Matlab function?

I am embarking on writing a Java wrapper for intlinprog, and learning Java at the same time. My OOP experience is C++ circa 2004, so it has been an interesting learning curve reading up on Java code idioms, patterns, Matlab data conversions, the packaging process itself, and the Java compilation/invocation.

intlinprog takes a struct argument named options. Is there an example of how to code up a MATLAB struct in Java? According to Rules for Data Conversion Between Java and MATLAB, "Structure arrays are constructed and accessed as arrays of MWArray". Most examples of Java/Matlab interoperation use classes derived from MWArray.

I am using Matlab Compiler SDK rather than the Matlab engine, so I assume that Java class com.mathworks.matlab.types.Struct does not apply. I welcome any corrections if I'm wrong.

Answer 1

[Todd Flanagan]

The eaiest way to learn how to create structs in the Java API is to add a sample in the Library Compiler tool with a sample struct and sample data. This will generate Java code that will show you how to use the struct api with your own data.

Here is an example:

a.i1 = 1.0
a.i2 = 'a string'

foo(a)

And the generated Java method:

public static void fooExample() {
		MWStructArray aIn = null;
		MWArray aIn_i1_1 = null;
		MWArray aIn_i2_1 = null;
		Object[] results = null;
		try {
			// instantiate data within struct aIn
			double aIn_i1_1Data = 1.0;
			aIn_i1_1 = new MWNumericArray(aIn_i1_1Data, MWClassID.DOUBLE);
			String aIn_i2_1Data = "a string";
			aIn_i2_1 = new MWCharArray(aIn_i2_1Data);
			// instantiate struct aIn and set inner data
			int[] aInDims = {1, 1};
			String[] aInFields = {"i1", "i2"};
			aIn = new MWStructArray(aInDims, aInFields);
			aIn.set("i1", 1, aIn_i1_1);
			aIn.set("i2", 1, aIn_i2_1);
			results = class1Instance.foo(aIn);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			// Dispose of native resources
			MWArray.disposeArray(aIn);
			MWArray.disposeArray(aIn_i1_1);
			MWArray.disposeArray(aIn_i2_1);
			MWArray.disposeArray(results);
		}
	}

[FM]

Wow. Thanks. I will decipher.