Assign callback to Java object prevents clearing of the MATLAB object

Hi, I have my own CalibrateTable class used as a MATLAB interface for custom Java table (modified JTable). Purpose is to have everything in one place and prevent other developers to directly access Java stuff - they will use objects of this class when manipulating table data. Problem arises when I want to assign callbacks to the table - it gets executed but I'm then not able to clear CalibrateTable class by "clear classes" command ("Cannot clear this class or any of its superclasses..."). The problem persists even when I pass something completely different than the object itself.

I include small part of the code:

classdef CalibrateTable < handle

   properties
      jScrollPaneHandle
      mTableHandle
      jTableHandle
      hTableHandle
    %other properties..
   end

   methods
   %some methods

    %constructor
    function obj = CalibrateTable(parent,position,tag)
      javaaddpath('Table.jar','-v0');
      rowtable = javaObjectEDT('Table');
      parentScrollpane = javaObjectEDT('javax.swing.JScrollPane', rowtable);
      [obj.jScrollPaneHandle, obj.mTableHandle] = javacomponent(parentScrollpane, position, parent);
      obj.jTableHandle = javaObjectEDT(rowtable);

      %get callback handle
      obj.hTableHandle = handle(obj.jTableHandle,'CallbackProperties');

      %add callback
      obj.hTableHandle.MousePressedCallback = @(src,event)CalibrateTable.DummyCallback(obj,src,event);
    end
   end

   methods(Static)
      function DummyCallback(varargin)
        disp('hello');
      end
   end

end

Any ideas? The class is cleared when I set the callback handle back to []/'' value so I've tried to explicitely define a constructor delete(obj) function but it is called only when the callback is set with no input arguments. onCleanup() does not seem to work for me as well.

Any help would be appreciated because I've already spent a ton of time on this issue...

edit> MATLAB 2010b/32bit/Win7

Answer 1

[Lawrence]

It's hard to tell for sure without access to your java class, but I think the following will work:

I'm assuming your "parent" is a Matlab object, not a Java object? If so, you can avoid this by explicitly tying the lifetime of your object to the parent with addlistener(). Of course, you'll still need to make sure that your tables are all closed before clearing the path.

You may also have to still explicitly clear the callback on deletion. I haven't tested it enough to be sure.

classdef CalibrateTable < handle
    properties
        jScrollPaneHandle
        mTableHandle
        jTableHandle
        hTableHandle
        %other properties..
    end
    methods
        %some methods
        %constructor
        function obj = CalibrateTable(parent,position,tag)
            javaaddpath('Table.jar','-v0');
            rowtable = javaObjectEDT('Table');
            parentScrollpane = javaObjectEDT('javax.swing.JScrollPane', rowtable);
            [obj.jScrollPaneHandle, obj.mTableHandle] = javacomponent(parentScrollpane, position, parent);
            obj.jTableHandle = javaObjectEDT(rowtable);
            %get callback handle
            obj.hTableHandle = handle(obj.jTableHandle,'CallbackProperties');
            %add callback
            obj.hTableHandle.MousePressedCallback = @(src,event)CalibrateTable.DummyCallback(obj,src,event);
            
            addlistener(parent,'ObjectBeingDestroyed',@(~,~)delete(obj));
        end
        function delete(obj)
            obj.hTableHandle.MousePressedCallback = [];
        end
    end
    methods(Static)
        function DummyCallback(varargin)
            disp('hello');
        end
    end
end