MATLAB BUILDER JA 2 Podręcznik Użytkownika Pobierz pdf (Strona 52)

3 Programming

Passing Argum ents to and from Java

When you invoke a method on a MATLAB Builder for Java component,

the input arguments received by the method must be in the MATLAB

internal array format. You can either conv ert them yourself w ithin the

calling program, or pass the arguments as Java d ata types, which are then

automatically converted by the calling mechanism.

To convert them yourself, use instances of the

MWArray classes; in this case

you are using manual conversion. Storing your data using the classes and

data types defined in the Java langu age means that you are relying on

automatic conversion. Most likely, you will use a combination of manual and

automatic conversion.

• “Manual C onversion of Data Types” on page 3-6

• “Auto matic Conversion to a MATLAB Type” on page 3-7

• “Specifying Optional Arguments” on page 3-9

• “Handling Return Values” on page 3-14

Manual Conversion of Data Types

To manually convert to one of the standard MATLAB data types, use the

MWArray data conv ersion classes provided by Java Builder. For class reference

information, see the

com.mathworks.toolbox.javabuilder package. For

extensive usage inf orm ation, see Chapter 4, “Using MWArray Classes”.

Code Fragment: Using MWNumericArray

The getmagic example shows manual conversion. The following code

fragment from that program shows a

java.lang.Double argument that is

converted to an

MWNumericArray type that can be used by the M-function

without further conversion.

MWNumericArray dims = null;

dims = new MWNumericArray(Double.valueOf(args[0]),

MWClassID.DOUBLE);

result = theMagic.makesqr(1, dims);

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MATLAB BUILDER JA 2 Podręcznik Użytkownika Strona 52