Access workspace variable from function within class

I have a table (DataTable) stored in a .mat file (Data.mat) that I want to be able to access in functions within a few different classes. I have a test class that stores a set of indices that correspond to rows in DataTable, and I would like to retrieve the values in these rows from a particular column of DataTable as a dependent property:

 classdef testClass

    properties 
        Indices double
    end

    properties (Dependent)
        Values double
    end

    methods
        function obj = testClass(ind)
           obj.Indices = ind; 
        end

        function val = get.Values(obj)
            load Data.mat
            val = DataTable{obj.Indices,1};
        end
    end  
 end

However, I will be changing the indices and accessing new values many times, and I don't want to have to load Data.mat every time. What I would like to be able to do is load Data.mat file once in a setup script and then access DataTable within testClass without loading it again. Two potential methods I'm aware of are to create a global variable for DataTable in my setup script, or to use evalin, but both of these seem to be discouraged. I'm wondering if there's another best practice for accomplishing something like this.

Answer 1

[Steven Lord]

Add a private or protected property to your class using the Access attribute on your properties block. In the constructor of the object, load the data and store it in the private/protected property. When you need to access it, do so from the private/protected property not the disk.

[J. Alex Lee]

And if you give that property the "constant" attribute, new instances of the class will have access to the table without having to load it again

[Jonathan Schmid]

Can you give an example of how to achieve that?

I.e., not having to write:

classdef Foobar
    properties(Constant = true)
        something = 5
    end
end

But instead being able to write:

data = 5; % perhaps loaded from a file, also needed for other purposes

classdef Foobar
    properties(Constant = true)
        something % have the data ("5") be assigned to here somehow
    end
    
    methods
        function this = Foobar(something)
            % perhaps through the constructor?
        end
    end
end

[Luis Ruiz]

An example is needed here.