CODEWITHSUNDEEP
matlabclassoop
Pedro.Alonso
Pedro.Alonso

Reputation: 1005

Undefined function 'addListener'

I'm reading the pdf book of Matlab OOP pdf and after implementing the code for the bank account chapter 3, it's complaining of something.

>> BA = BankAccount(1234567, 500)
    Undefined function 'addListener' for input arguments of type 'BankAccount'.
Error in AccountManager.addAccount (line 20)
            lh = addListener(BA, 'InsufficientFunds', @(src,
            ~)AccountManager.assignStatus(src))
Error in BankAccount (line 21)
            BA.AccountListener = AccountManager.addAccount(BA);

I have no idea why is this as I followed the example given, as:

classdef BankAccount < handle
    %UNTITLED Summary of this class goes here
    %   Detailed explanation goes here
    properties (Access = ?AccountManager)
    AccountStatus = 'open'
    end
    properties (SetAccess='private')
        AccountNumber
        AccountBalance
    end
    properties (Transient) %not saved
        AccountListener
    end
    events
        InsufficientFunds
    end
    methods
        function BA = BankAccount(AccountNumber, InitialBalance)
            BA.AccountNumber = AccountNumber;
            BA.AccountBalance = InitialBalance;
            BA.AccountListener = AccountManager.addAccount(BA);
        end

        function deposit(BA, amt)
            BA.AccountBalance = BA.AccountBalance + amt
            if BA.AccountBalance > 0
                BA.AccountStatus = 'open'
            end
        end

        function withdraw(BA, amt)
            if (strcmp(BA.AccountStatus, 'closed') && BA.AccountBalance <= 0)
                disp(['Account', num2str(BA.AccountNumber), 'has been closed'])
                return
            end
            newBal = BA.AccountBalance - amt
            BA.AccountBalance = newBal
            if newBal < 0
                notify(BA, 'InsufficientFunds')
            end
        end

        function getStatement(BA)
            disp('-----------')
            disp(['Account', num2str(BA.AccountNumber)])
            ab = sprintf('%0.2f', BA.AccountBalance)
            disp(['Current Balance', ab])
            disp(['Account Status', BA.AccountStatus])
            disp('-----------')
        end

    end
    methods (Static)
        function obj = loadObj(s)
            if isstruct(s)
                accNum = s.AccountNumber
                initBal = s.AccountBalance
                obj = BankAccount(accNum, initBal)
            else
                obj.AccountListener = AccountManager.addAccount(s)
            end
        end

    end


end

And:

classdef AccountManager
    %UNTITLED2 Summary of this class goes here
    %   Detailed explanation goes here

    properties
    end

    methods (Static)
        function assignStatus(BA)
            if BA.AccountBalance < 0
                if BA.AccountBalance < -200
                    BA.AccountStatus = 'closed'
                else
                    BA.AccountStatus = 'overdrawn'
                end
            end
        end

        function lh = addAccount(BA)
            lh = addListener(BA, 'InsufficientFunds', @(src, ~)AccountManager.assignStatus(src))
        end

    end

end

So could anyone tell me what is going on here? Is on Matlab R2014a(8.3.0.532). I think I have implemented correctly but not copy pasted, maybe I overlooked a line. Thanks.

Upvotes: 2

Views: 268

Answers (1)

rayryeng
rayryeng

Reputation: 104474

That's because the way you spelled the method is slightly incorrect. It's called addlistener - lower case l. You have an upper case L when you spelled it.

The book you're referencing is MATLAB's official Object Oriented Programming guide - http://www.mathworks.com/help/pdf_doc/matlab/matlab_oop.pdf. The code in question is on Page 3-16.

Remember, MATLAB is case-sensitive. Even if the characters are different cases, it will be interpreted as different variables, functions, etc. Don't worry - I think addListener is more natural as there are two words. addlistener is just... weird!

Upvotes: 3

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