Build a java applet to do integer infix expression processing. Design an interface with an “expression” text field, and buttons to calculate and clear. (You may use any interface as long as it is simple, elegant and intuitive). You should be able to detect errors: “illegal character”, “missing operand”, “mismatched parentheses”, “missing operator”, “division by zero”. Blanks are allowed anywhere between operators and operands.

This project should have the following classes:

• The GUI – may be the applet itself
• A static precedence/arithmetic class – to determine which of two operators has higher precedence. A method to “do one operation and return result” is also handy.
• A stack that takes a generic data type. You will need two instances of this, one for String or some other char wrapper, and one for Integer (the int wrapper).
• Something like StringTokenizer to enable you to retrieve tokens from the input String. (You may use the java class).
• A StackException to be thrown on overflow or underflow.
• Provision for Error handling. A class that returns a string for an error code is one way to do it.