CIT 591 Assignment 9: Text Translator Notes
Fall 2008, David Matuszek

The screenshot shows an Edit menu. It should be a File menu.

Each of the four translators (Identity, etc.) is a class that implements TranslatorInterface.

The Translator class is the main class. It should extend JFrame. If you prefer, it can instead create and use a JFrame (but it's usually easier just to extend JFrame).

The addTranslateItem(TranslatorInterface translator) method is just a GUI building method. It doesn't do anything fancy--for example, it doesn't let the user add menu items to a running program! All it does is:

• It gets the name of the translator, creates a menu item with that name, and adds the menu item to the Translate menu.
• It attaches a listener to the menu item. You should have just one listener that is shared by all the menu items in the Translate menu. You have to write a class that implements ActionListener. Each time you call addTranslateItem, it creates an new object of your ActionListener, and saves the parameter translator in an instance variable. When your ActionListener is used, it uses this instance variable to get the name and description and to do the translation.

To add yet another translator (class that implements TranslatorInterface) to the program, all you should have to do is create a new translator of that type, and add a call to addTranslateItem in your GUI building method.

Here's what the "translate" listener does:

• It selects the translator.
• It gets the name of the selected translator, and puts it in the title bar.
• It gets the description of the selected translator, and puts it just under the title bar.
• It gets the text from the upper text area, uses the selected translator to translate it, and puts the result in the lower text area.

The program does only one kind of translation at a time. It does not do all four at once.

Here's the way translation should work.

• At all times, exactly one of the possible translations is selected. The name of the selected translation is displayed in the title bar; its description is displayed immediately below. When the program first starts up, the selected translation should be the Identity translation.
• If you click the Translate button, the currently selected translation is applied to the text in the upper text area, and the result is displayed in the lower text area.
• If you select a translation from the Translate menu, that translation becomes the selected one, and that translation is applied to the text in the upper text area, displaying the result in the lower text area. That is, you do not need a separate click of the Translate button.

The purpose of the Wrap Lines translator is to break annoyingly long lines. It should never join two lines.

For my translator,

• I used a JTextArea to hold the translator description. To make it fill the area, I put it in the CENTER of a BorderLayout.
• For each of the other two text areas, I used a JTextArea inside a JScrollPane inside a JPanel. (You can find JScrollPane in my SwingExamples.jar program if you look hard enough.) I also used a TitledBorder, but you don't have to get that fancy.