Activity 4.6 - Writing a user-defined exception class

Topic

Here we extend the previous activity to employ a user-defined exception class.

Materials

In addition to the Solution document, the project for this activity contains three classes:

• Read_a_Sonnet, which you will need to modify;
• FileFormatException, which is incomplete;
• Main, which contains test code for the activity.

In addition, there is a text file, sonnet1.txt, which can be found in the project folder. This contains a well-known sonnet (a fourteen-line poem) by William Shakespeare.

Task

The run method of the class Read_a_Sonnet will read the first fourteen lines of the file sonnet1.txt and will print them out one by one. The main method should handle any exceptions of type IOException that may occur.

Instructions

1. Run the project and check that it displays the fourteen-line poem correctly.
2. Open the class FileFormatException, and complete the definition of this user-defined exception class.
3. In class Read_a_Sonnet, make appropriate changes so that the relevant methods throw and handle a FileFormatException, rather than an EOFException, if the file does not have enough lines.
4. Check that your modified classes work both for a file with at least the required number of lines (14) and for a shorter file (edit the text file in the IDE).