Programming

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.
• indAssets -- The array of asset subclass objects (stock, bond, savings).
• totalValue -- The total value of all assets. The constructor calculates this value from the objects passed in as arguments.
• accountNumber -- 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.totalValue = 0;
      p.indAssets = {};
      p.accountNumber = '';
      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.totalValue = 0;
      for k = 1:length(varargin)
          p.indAssets(k) = {varargin{k}};
          assetValue = get(p.indAssets{k},'CurrentValue');
          p.totalValue = p.totalValue + assetValue;
      end
      p.accountNumber = '';
      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

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