A Currency Converter

A Currency Converter Application The application you develop shall enable the user to easily convert money between British Pound and Euro. The graphical user interface shall consist of a single window with a menubar. Approximately at the centre of the window should be a label that shows a number (which may include a decimal point), e.g. 22.5. We call this the money label. Below the label the window shall contain buttons for the digits 0 to 9, the decimal point \.", a button for deleting the rightmost symbol of the label (digit or decimal point), and a button for resetting the money label to 0. These buttons should be arranged similarly to the number block of an ATM. So by clicking these buttons the user can change the money label. Note that the money label should not take any input from the computer keyboard. When the program starts, the money label shall be 0. Additionally, above the money label, the window shall contain two buttons, one for each currency, British Pound and Euro. At any time exactly one of these two buttons is selected. At program start the British Pound button shall be selected. When the user changes the selection to the other button, the amount in the money label is converted from the previously selected currency into the newly selected currency. The menubar comprises three menus: File, Currency and Help. The File menu has only one option, quitting the application. The Currency menu lists the two currencies British Pound and Euro. It provides an alternative means for choosing the currency. The Help menu provides a Help entry, which shows on selection a dialogue box with some basic use instructions, and an About entry, which shows on selection in a dialogue box the name of the programmer. The application window should have a reasonable layout, even when the user changes its size. Enforce a reasonable minimal size of the window. Implementation Requirements: The program shall consist of at least three classes: 1. A class ConverterGUI implements the graphical user interface. The object controls the whole application. 2.  A class FloatInput implements the content of the money label. Its methods translate key inputs to a string and a floating point number (e.g. the key inputs 7, . and 2 are translated into the string "7.2" and number 7.2). Note that this class is independent of the GUI; it could be used also if the currency converter did take input from a hardware keyboard.  A class Money implements the actual conversion between currencies. At runtime there should exist one object of each class. The ConverterGUI object will reference the other two objects. You may decide to use additional classes for other purposes. The constructor of the ConverterGUI class shall take a double parameter, which is the exchange rate between the two currencies. That is, this parameter states the current value of 1 GBP in Euro. Ensure that every class and every method comes with a JavaDoc comment, which brie y describes its purpose and the purpose of arguments and return values (for meth- ods). For some states of the application some inputs make no sense. For example, if the money label contains a number that has a decimal point, then a second decimal point makes no sense. Also the money label should never have leading zeros, that is, something like 0004.30. For easy usability, ensure that the user cannot select a button or menu item that does not make sense for the current state of the application. The application shall avoid any money amount with more than two digits after the decimal point. First, that means that conversion always rounds the result to at most two digits after the decimal point. Second, the user may enter any number into the money label, but if the number has more than two digits after the decimal point, then conversion should raise an exception. The user interface should catch this exception, display an appropriate error message, and continue without performing the conversion or otherwise changing the money label.