Design Problem in Java

Question

Problem definition:
Consider the following !!
You are writing the s/w for an interface to an appliance and the interface has the following things on it !!
1) three buttons - reset clear and power on/off !!
2) LCD display which shows error messages thrown by the appliance
3) a up down scroll button which helps us scroll through the messages
4) lights - white light for power on/off and red for error on the machine
and green for machine working fine !
Now i need to design all the classes that are required to solve this problem and i need to answer questions like if i am using Multiple inheritance why am i doing so or if i am using composition then why is that !!!
My idea is as follows is put below .. i need to modify this idea and make it better .. please suggest a better mechanism to make it more generic and to support more code reuse ability !
My Solution:
I have found the following relationships !
1) power on button and the power LED are related
2) the messages on the LCD and reset and clear buttons are related !!!
3) messages and scroll buttons are related
now lets decide what all classes are required and the relationships between the various classes !!
we cannot use inheritance .. i don't see any way of doing that .. so we have to use composition !!
1) we will use the concept of inner and outer classes !!
2) let the outer class be a class called myInterface which will have a method called lcdDisplay()
3) and let there be an inner class called button, i am making button a class because button is the most imp. object because all methods depends on the status of the button.
4) so myInterface has a button (composition relationship) !
My rough code would look like this .......
class myinterface
          // An LCD string is defined which is buffer which holds error messages
          // Various LIGHT variables (defined as boolean) are created and their values are initialized to be OFF
     lcdDisplayAll()
          print all errors on the lcd
          CHECK IF ERROR IS FATAL if yes make RED LED status TRUE and AMBER FALSE.
          else
          CHECK IF ERROR IS FATAL if no make RED LED status FALSE and AMBER TRUE.
     class mybuttons
getButtonStatus();
     if (getButtonStatus == 1)
POWER is ON so do all the functions
     if (getButtonStatus != 1)
POWER is OFF so dont do any functions
     myScrollUp()
decrement message index.
     lcdDisplayAll();
     myScrollDown()
increment message index.
     lcdDisplay();
please suggest changes !

Answer 1

srijan_capsilon wrote:
please suggest changes !No, I am not going to suggest changes: that would mean doing your work. If you have a specific Java related question, feel free to post it here. But it looks like you hardly know any Java, in which case I recommend you do some tutorials:
[http://java.sun.com/docs/books/tutorial/]
Good luck.