No Digits

Problem 1:

Write an exception class NoDigitsException.

• This exception should include the message "No digits found"
• Whenever an exception of this type is created, add an entry to a log file"NoDigitsException log.txt"
  • time/date stamp (look up the Javadoc for Date class)
  • The string that was entered to cause the exception

Note: use the append method of file operations. Explanation and example can be found at https://docs.oracle.com/javase/tutorial/essential/io/file.html

Problem 2:

In keeping with robust programming principles, you need the ability to ask the user for a number and handle anything they type into the keyboard without crashing your program. Write a support class Keyboard that include methods getInt() and getDouble(). Polymorph them with versions that accept a String parameter to provide as a prompt.

These methods do the following:

• Print the prompt (for the prompt versions), accept keyboard String input.
• If no digits occur in the input, throw a NoDigitsException.
• Remove all characters except for digits and (for the doubles) the first decimal point.
• (for the doubles) add a 0 if no other digits occur after the decimal.
• Parse the remaining String to int/double and return the result.

Problem 3:

Write a test class to verify your Keyboard class operates correctly by asking the user for ints and doubles using both the prompted and non-prompted versions (provide a prompt as needed before calling the method).

• catch any NoDigitsException and print the exception message.
• continue to ask for numbers until two NoDigitsExceptions have been thrown. Exit when the second exception is thrown.

Construct and submit a UML diagram of these classes.