Design process

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• a simple applet that models a bank account manager
• keeping track of the balance, handling withdrawals, handling deposits, and providing the balance
  
  
• What are the components of this system?
• the visible and the hidden parts
  
  
• BankAccount
  • any visible attributes i.e. public fields ?
  • What does this class do? i.e. public methods
    
    

    Deposit:

    Increase the balance of the account by the specified amount of money.

    Withdraw:

    Decrease the balance of the account by the specified amount of money.

    Balance (inquiry):

    Return the current balance of the account with the amount of money specified as a decimal number such that the integer represents the dollars and the fractional component the cents.

    Get name:

    Return the name of account, so the user can be informed of the account that is being operated.
    
    

    Constructor:

    Create an account for the person whose name is specified as a String. Set the beginning balance to 0.00.

    
    
  • internal represenatation of a bank account (hidden attribute)
    
    

    Balance:

    the total amount of money in the account represented as a decimal number, with the dollars represented as the integer component and the cents represented as the fractional component.

    Name:

    the name of the account, a user-friendly String. In the case of the example, the name is "Yuechao Gao"

  • 
    

    Class name	BankAccount
    Visible attributes	nil
    Hidden attributes	Balance Name
    Visible Behaviors	Deposit Withdraw Balance inquiry Get name Constructor:
    Hidden behaviors	?

  
  
• Bank Account Applet
  
  
  • visible attributes i.e. public fields ?

    Text component:

    This should allow the user to enter a dollar amount for deposit or withdrawal, as display the balance, if requested by the user.

    Deposit, withdraw and balance check boxes:

    These are used to allow the user to select the next operation.

    Operation panel:

    A panel used to hold the three checkboxes in a vertical configuration.

    Main panel:

    A panel used to position the

    Execute button:

    The button that the user presses to initiate the selected operation.

    Account name label:

    Displays "Account Name:" and the name of the account, in the example case, "Yuechao Gao"

    Instruction label:

    The label that instructs the user about the proper input format.

    Input panel:

    The panel, organized with 1 row of three columns that holds each of the input components, as shown.

    Applet, itself:

    The applet, itself, that is organized with one column of two rows. The top of which holds the input panel and the bottom of which holds the instruction label.

    
    
  • Behaviors
    
    Execute: Takes one of the three actions described below, depending on the state of the operation checkboxes:

    Deposit:

    Ask the BankAccount object to add the amount specified by the user to the account.

    Withdraw:

    Ask the BankAccount object to subtract the amount specified by the user from the account.

    Balance:

    Ask the BankAccount object to report the current balance of the account, and then display this amount in the text field.

    
    
  • Hidden attributes:
    
    

    Bank account:

    An instance of the BankAccount class to keep track of the money

  • 
    

    Class name	BankAccountApplet
    Visible attributes	Text field Deposit, withdraw and balance check boxes Main, input, and operation panels Execute button Account name, and instruction labels Applet
    Hidden attributes	Bank account
    Visible Behaviors	Deposit Withdraw Balance inquiry Execute
    Hidden behaviors	?

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