In this homework, you will work with the String class to better familiarize yourself with
it. You also will do more with applets and graphics, utilizing the Random class to help in
the second part.
On the last HW assignment, you began to learn about javadoc. As you’ll recall, Javadoc
is an application that is part of the JDK that you downloaded. You can run it on the
command line by typing “javadoc *.java” which will create documentation for all the
classes in your current directory. If you are using JGrasp, you can invoke javadoc by
using Project->Generate Documentation from the pull-down menu. Javadoc creates the
nice web-page based documentation that we have been using in class (the API).
Remember from class we said that javadoc comments were a special form of
comment. Javadoc recognizes a comment that starts with /** as a javadoc comment.
You should continue to use Javadoc comments on this assignment. All classes you
create from now on should have a descriptive Javadoc comment, just like in homework
Assignment 3.1: Leetspeak Translator
[From Wikipedia]: Leet or Eleet (sometimes rendered l33t, 1337 or 31337), also known
as Leetspeak or Leetzorz (1337Z0l2Z), is an alphabet used primarily on the Internet,
which uses various combinations of ASCII characters to replace Latinate letters (see
http://en.wikipedia.org/wiki/Leet_speak for more details).
Your assignment is to write a program that translates English into simple leetspeak.
Call this program LeetTranslator.java. The user will enter a sentence in English and you
are to translate it into leetspeak given the following set of rules:
• “@” is equal to “a”
• “3” is equal to “e”
• “1” (one) is equal to “i”
• “$” is equal to “s”
• “0” (zero) is equal to “o”
We have not covered conditionals in Java yet, but you do not need them on this
assignment. Also, you do not need to handle any other translations apart from those
Example (user input in bold):
Enter string to translate: johannes thinks he is so cool, but he’s not
j0h@nn3$ th1nk$ h3 1$ $0 c00l, but h3’$ n0t
Assignment 3.2: Mood Ring
JohannesCorp is considering manufacturing mood rings and Marketing wants you to
simulate them using an applet. The mood rings are to be very cheap and of poor
quality, so they turn a random color and change randomly regardless of the user’s
actual mood. Thus, Marketing has given you the following specifications for your
• The ring’s color should be completely random (use the Color constructor with
random parameters, and be sure to check the API if you need it).
• The ring should be displayed with a random diameter.
• The ring’s color and diameter should change every time the user runs the
program or resizes the applet.
• The center of the ring should be at the center of the applet, even if the window is
• The ring should not extend beyond the edge of the applet window (you can
assume the applet will always be square).
• The ring should have a reasonable minimum size so it always displays properly
(that is, the ring should still be visible even at the smallest size) so you will need
to think about your range of random numbers when choosing a diameter.
Call the program MoodRingApplet.java. Also, make an HTML page
(MoodRingApplet.html) to display your applet.
Because the background drawing code behavior has changed in Java 6, you can use a
fillRect which covers the entire applet to mimic a background (the background does
not have to be a random color). Remember to handle resizing windows!
Here is an example of the mood ring applet:
Note that if I resize the applet above, the ring should be redrawn so it remains in the
center (and it would be drawn with a new random color and random size).
Ambitious people: you can optimize the ring to fit in any size window, square or not, by
using the Math.min method (look at the Java API for details) to determine whether
width or height is the constraint, but it is not required. As long as your ring fits within a
square applet when resized, you will receive full credit for that criteria.
Turn in the following files on T-Square:
Don’t forget to javadoc all .java files and include a collaboration statement.
Extra credits are advanced topics that will test your programming mettle! In total,
these will be worth 5 extra points each. These will not be covered in class, so you’ll
have to figure out how to do them on your own (of course, you may consult friends,
TA’s, and the Internet). If you attempt these, and your normal program doesn’t work
properly, or the extra credit is broken and interrupts a required feature, you won’t get
points for either. Attempt this only after you’ve submitted a working assignment. If you
do the extra credit, make sure to mention it in your javadocs!
How difficulty ratings work:
0: Trivially easy.
5: Challenging. Involves topics you might not know yet.
10: Involves topics from all across the course. Designed to be difficult.
Homework 3 Extra Credits:
1. (Difficulty: 3/10) Allow your program to translate from Leet back to normal. When
your program starts up, you’ll need to ask the user which type of conversion
they would like to do. To do this, you need to know how if() conditionals work.
2. (Difficulty: 8/10) The mood ring should change colors periodically. To do this,
you’ll need to understand the Timer and Actionlistener classes, as well as how
to force an applet to repaint. You should generate a random color for the mood
ring to switch to. 1 second is the suggested delay for the Timer.