Implicit java object variable initializaton or declare

Question

raym 2019-3-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/451223-implicit-java-object-variable-initializaton-or-declare

A function Miji() load a mij.jar file defined in matlab's static javaclasspath.txt by this way:

function Miji
    ...
    MIJ.start(); % the mij.jar defines a MIJ static object and can be directly loaded
    ...
end

In a matlab session, a MIJ can be created only once in the first time by either by calling

MIJ % creat a MIJ object
ans =
 
MIJ@73862f81

or by calling

MIJ.start() % this not only create MIJ, but also initialize a GUI window

or by calling

Miji(); % this not only create MIJ, but also initialize a GUI window

===========

Now I have a function that use MIJ object as argument. To make a test in case of no argument, usually I wrote a ~nargin block in the beginning.

function dosomething(MIJ,......)
if ~nargin
    Miji(); % call MIJI() to establish MIJ in the first time
    arg2 = 1;
    arg3 = 22;
    %...
end
MIJ.run('some command')
end

If I run it without argument , the error is :

Not enough input arguments.
Error in dosomething (line 12)
MIJ.run('Close All');

However, if I delete the 1st argument, then it runs OK.

function dosomething(......)
if ~nargin
    Miji(); % call MIJI() to establish MIJ in the first time
    arg2 = 1;
    arg3 = 22;
    %...
end
MIJ.run('some command') % because MIJ was not decleared as input or variable, so it goes into the mij.jar to find the class MIJ
end

Also, if I call it with argument, it also runs OK.

Miji();
dosomething(MIJ,2,34,134)% use original version. 
% In this scenario, MIJ was a static class that exist in memory, although MIJ is always not in the matlab variable list.

So the problem is that declare the MIJ as an argument of a function prevent its alternative as a static java class of the same name.

So to make the function runs without argument and without Miji() called beforehand in a new matlab session, how to modify the code to make it works?