EDU.ksu.cis.calculator.javamodel
Class CalculatorImpl

java.lang.Object
  |
  +--EDU.ksu.cis.calculator.javamodel.CalculatorImpl

All Implemented Interfaces:

Calculator

public class CalculatorImpl

extends Object

implements Calculator

A model for an RPN calculator using the BigInteger class.

Author:

Rod Howell (howell@cis.ksu.edu)

Constructor Summary

CalculatorImpl(CalculatorUI v)
Constructs a new CalculatorImpl using the given user interface and base 10.

CalculatorImpl(CalculatorUI v, int b)
Constructs a new CalculatorImpl using the given user interface and base.

Method Summary

void	changeSettings(Object change, String input) Changes the settings of the calculator.
void	doOperation(Operation op, String input) Performs the given operation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CalculatorImpl

public CalculatorImpl(CalculatorUI v)

Constructs a new CalculatorImpl using the given user interface and base 10.

CalculatorImpl

public CalculatorImpl(CalculatorUI v,
                      int b)

Constructs a new CalculatorImpl using the given user interface and base.

Method Detail

doOperation

public void doOperation(Operation op,
                        String input)
                 throws EmptyDequeException,
                        NumberFormatException,
                        Exception

Performs the given operation. If input is non-null, it is treated as the top of the stack. If input is "" or "-", it is interpreted as "0". Operands are taken from the top of the stack so that the top element is the last operand. The result (if any) is pushed onto the stack. When the operation is complete, the element that then resides at the top of the stack (if any) is reported to the user interface. If an exception or error is thrown, the stack will be restored to its original contents, if possible.

The following classes of operations are supported:

• Push - If input is null, a copy of the top of the stack is pushed. Otherwise, input is simply accepted as the new top of the stack. Unrecognized subclasses of Operation are treated as Push.
• Pop - Removes the top from the stack.
• ClearStack - Empties the stack.
• RotateUp - Moves the element at the bottom of the stack to the top.
• RotateDown - Moves the element at the top of the stack to the bottom.
• ConvertBase - Converts the top of the stack to the base specified by op.getBase(). If the stack is empty, simply reports the new base to the user interface.
• EncodedOperation - Performs the operation specified by the given subclass of EncodedOperation.

Specified by:

doOperation in interface Calculator

Throws:

EmptyDequeException - If the operation requires more operands than are present on the stack.

NumberFormatException - If input contains an invalid character for the current base.

Exception - If the given operation throws an exception.

changeSettings

public void changeSettings(Object change,
                           String input)

Changes the settings of the calculator. As there are no settings to change in this model, this method does nothing.

Specified by:

changeSettings in interface Calculator

Parameters:

change - Encodes the change to the settings.

input - May contain input affected by the change.