MATLAB: How to return multiple parameters from Matlab to a Java program

Question

I am making a Java program that must call some matlab functions. I have received some simple test programs to play with so I can learn how it all works.

My problem is that one of the matlab test programs returns two parameters, but in my Java program I only see/get one.

Here is the matlab code:

function [out1,out2]=test_Java5(in1,in2)
%


%   [out1,out2]=test_Java5(in1,in2)
%
%   out1='ABC';
%   out2='DEF';
%
disp(in1);
disp('');
disp(in2);
out1='ABC';
out2='DEF';
end

Here is the Java method that calls matlab and prints output:

    private static void testJava5(Testfunctions test) {
      MWCharArray a = null;
      MWCharArray b = null;
      Object[] result = null;
      
        try {
          System.out.println("Starting testJava5");
          a = new MWCharArray("Mary Smith");
            b = new MWCharArray("John Doe");
            result = test.test_Java5(1, a, b);
            System.out.println("Results=" + result.length);
            for (int i=0; i < result.length; i++) {
              System.out.println("Type=" + result[i].getClass() + ", Result=" + result[i]);
            }
            System.out.println("Finished testJava5");
        } catch (Throwable t) {
            t.printStackTrace();
        } finally {
            a.dispose();
            b.dispose();
            MWArray.disposeArray(result);
        }
    }

Here is the output from my Java program:

Starting testJava5
Mary Smith
John Doe
Results=1
Type=class com.mathworks.toolbox.javabuilder.MWCharArray, Result=ABC
Finished testJava5

As you can see from the output, matlab prints out the two input parameters given to it, but the Java program only receive one parameter back as a MWCharArray (string).

I would have expected that my result array contained two records, or that result[0] was of type MWArray which contained the two MWCharArrays. But apperently not.

What am I doing wrong here?

PS: I know that I can use a struct instead, but we have a very complex set of input and outputs that would make it easier if it was separated.

Answer 1

AFAIK, the first argument that you pass into the method is the expected number of output arguments. So all you need to do is change:

   result = test.test_Java5(1, a, b);

to:

   result = test.test_Java5(2, a, b);