MATLAB BUILDER JA 2 Podręcznik Użytkownika Pobierz pdf (Strona 74)

3 Programming

Handling Data Conversion Between Java and MATLAB

The call signature for a method that encapsulates a MATLAB function uses

one of the MATLAB data conve rsio n classes to pass arguments and return

output. When you call any such method, all input arguments not derived

from one of the

MWArray classes a re converted by Java Builder to the correct

MWArray type before being passed to the MATLAB method.

For example, consider the following Java statement:

result = theFourier.plotfft(3, data, new Double(interval));

The third argument is of type java.lang.Double, which converts to a

MATLAB 1-by-1

double array.

Calling MWArray Methods

The conversio n rul es ap pl y no t only when calling your own methods, but

also when calling constructors and factory methods belonging to the

MWArray

classes. For examp l e, the following code calls the constructor for t he

MWNumericArray class with a Java double input. Java Build er con verts

the Java

double input to an instance of MWNumericArray having a ClassID

property of MWClassID.DOUBLE. This is the equivalent of a MATLAB 1-by-1

double array.

double Adata = 24;

MWNumericArray A = new MWnumericArray(Adata);

System.out.println("Array A is of type " + A.classID());

When you run this example, the results are as follows:

Array A is of type double

Specifying the Type

There is an exception: if you supply a specific data type in the same

constructor, Java Builder converts to that type rather than following the

default con vers ion rules. Here, the code specifies that

A should be constructed

as a MATLAB 1-by-1 16-bit integer array:

double Adata = 24;

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MATLAB BUILDER JA 2 Podręcznik Użytkownika Strona 74