Programming and Data Types

The Portfolio Constructor Method

The portfolio constructor method takes as input arguments a client's name and a variable length list of asset subclass objects (stock, bond, and savings objects in this example). The portfolio object uses a structure array with the following fields:

• name - The client's name.
• ind_assets - The array of asset subclass objects (stock, bond, savings).
• total_value - The total value of all assets. The constructor calculates this value from the objects passed in as arguments.
• account_number - The account number. This field is assigned a value only when you save a portfolio object (see Saving and Loading Objects).

function p = portfolio(name,varargin)
% PORTFOLIO Create a portfolio object containing the 
% client's name and a list of assets
switch nargin
case 0
    % if no input arguments, create a default object
    p.name = 'none';
    p.total_value = 0;
    p.ind_assets = {};
    p.account_number = '';
    p = class(p,'portfolio');
case 1
    % if single argument of class portfolio, return it
    if isa(name,'portfolio')
        p = name;
    else
        disp([inputname(1) ' is not a portfolio object'])
        return
    end
otherwise
    % create object using specified arguments
    p.name = name;
    p.total_value = 0;
    for i = 1:length(varargin)
        p.ind_assets(i) = {varargin{i}};
        asset_value = get(p.ind_assets{i},'CurrentValue');
        p.total_value = p.total_value + asset_value;
    end
    p.account_number = '';
    p = class(p,'portfolio');
end

Constructor Calling Syntax

The portfolio constructor method can be called in one of three different ways:

• No input arguments - If called with no arguments, it returns an object with empty fields.
• Input argument is an object - If the input argument is already a portfolio object, MATLAB returns the input argument. The isa function checks for this case.
• More than two input arguments - If there are more than two input arguments, the constructor assumes the first is the client's name and the rest are asset subclass objects. A more thorough implementation would perform more careful input argument checking, for example, using the isa function to determine if the arguments are the correct class of objects.

Example - The Portfolio Container

The Portfolio display Method