Hubert Halim - Project Portfolio

Whenever the user attempts to set a new Budget, ExpenseLa will create a new MonthlyData object with the given amount. The application will then call ModelManager#setMonthlyData(MonthlyData toSet). During the creation of the new MonthlyData, the Budget class will internally check if the budget amount is valid.

We will demonstrate what happens at the back-end whenever the user sets a budget:

Case 1. The user wishes to set their budget to $1500, non-recurring. They execute the command: budget b/1500. The user’s entry is checked by BudgetCommandParser#parse() and an attempt to parse each parameter occurs:

Since the user input is valid, the Budget is successfully created and inserted into a newly created MonthlyData.

Case 2. The user made a typo when setting their budget. They execute the command budget b/1500. The user’s entry is checked by BudgetCommandParser#parse() and an attempt to parse each parameter occurs:

Budget class then is attempted to be created with the parsed budget amount in the constructor. Internally Budget will do a validity check using Regex and throw a ParseExection since amount is not valid.

Case 3. The user wishes to set their budget to $1500, recurring. They execute the command: budget b/1500 rc/. The user’s entry is checked by BudgetCommandParser#Parse() and an attempt to parse each parameter occurs:

Since the user input is valid, the Budget is successfully created and inserted into a newly created MonthlyData. BudgetCommand will then modify GlobalData in Model by calling Logic#setGlobalData. RecurringBudget value in GlobalData is now set to the new Budget

The sequence diagram below depicts what was just elaborated:

We have considered various ways as to how Budget should be stored in ExpenseLa. In this section, we will explain the rationale on our course of actions.

Every time the user key in a command and press Enter, CommandBox#handleCommandEntered method will be called. The method will attempt to execute the command by calling CommandExecutor#execute method. That method throws an error if command is invalid. So if the command is valid, the CommandBox#handleCommandEntered method will call Logic#deleteCommandFromHistory to delete the command if it exists in the current command history. It will then call Logic#addToCommandhistory to add the command to the command history as its latest entry. Both commands for add and delete takes in an integer variable called offset. This variable is maintained by CommandBox and determines which command the user is currently at in the command history. Offset starts from -1 indicating CommandBox is empty and resets to -1 every time a successful command is entered

Command History is an array list that resides in ModelManager object. It can be accessed through Logic by calling

The diagrams below depicts what was just elaborated:

We have considered various ways as to how to implement CommandHistory to support navigation to previous commands Since we need to capture keyboard events when user press the keyboard, we decided to implement the event listener and handler in CommandBox component as it is more convenient because when a keyboard event is captured, the app can straight away modify the TextField in CommandBox. Since the event when user enter a command is also handled in CommandBox and we only store successful commands in CommandHistory, we wait for execution of the Command by CommandExecutor, if it is successful, the String for the command is added to, otherwise due to the error thrown and caught somewhere else, the command is not stored.