Question

i’m writing my first MATLAB O-O application and i’m confused about the implementation of compositions, aggregations and relationships in general.

My question is: how to implement an aggregation or an association one-to-many in matlab? Where i can take some examples?

Moreover, i’m using ArgoUml to design my application, is there any plugin to automatic code generation in matlab?

Thanks in advance

Answer 1

Here is a quick example of class association. The scenario consists of a course that can have many students enrolled:

Student.m

classdef Student < handle
    properties
        name
    end
    methods
        function obj = Student(name)
            if nargin > 0
                obj.name = name;
            end
        end
        function delete(obj)
            fprintf('-- Student Destructor: %s\n',obj.name);
        end
    end
end

Course.m

classdef Course < handle
    properties
        name        %# course name
        std         %# cell array of students
    end
    properties(Access = private)
        lastIdx = 1;
    end
    methods
        function obj = Course(name, capacity)
            obj.name = name;
            obj.std = cell(capacity,1);
        end
        function addStudent(obj, std)
            if obj.lastIdx > numel(obj.std)
                fprintf(2, 'Sorry, class is full\n');
                return
            end
            obj.std{obj.lastIdx} = std;
            obj.lastIdx = obj.lastIdx + 1;
        end
        function printClassRoster(obj)
            fprintf('Course Name = %s\n', obj.name);
            fprintf('Enrolled = %d, Capacity = %d\n', ...
                obj.lastIdx-1, length(obj.std));
            for i=1:obj.lastIdx-1
                fprintf('ID = %d, Name = %s\n', i, obj.std{i}.name);
            end
        end
    end

end

And here is a code to test the above classes:

c = Course('CS101', 3);
for i=1:4
    name = sprintf('amro%d',i);
    fprintf('Adding student: %s\n', name)
    c.addStudent( Student(name) )
end

fprintf('\nClass Roster:\n=============\n')
c.printClassRoster()

fprintf('\nCleaning up:\n')
clear c

The output:

Adding student: amro1
Adding student: amro2
Adding student: amro3
Adding student: amro4
Sorry, class is full
-- Student Destructor: amro4

Class Roster:
=============
Course Name = CS101
Enrolled = 3, Capacity = 3
ID = 1, Name = amro1
ID = 2, Name = amro2
ID = 3, Name = amro3

Cleaning up:
-- Student Destructor: amro1
-- Student Destructor: amro2
-- Student Destructor: amro3