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Class designer.LogicalOperation 

java.lang.Object
   |
   +----designer.LogicalOperation
public class LogicalOperation
extends Object
Class: Logical Operation

Purpose:
This class provides our design problem solver the capability of evaulating
logical expressions. Architecturally, logical expression are super-sets of
arithmetic expressions, as logical expression can contain arithmetic
expressions. This class will be RPN stack-based, with the ability to
accept "Calculation"s as operands. Supported logical operators are >, >=
<, <=, !=, =, && (and), || (or), ^ (xor). The parameters are pushed first,
followed by the logical operation.
For example, the following calls would result in the expression: x <= y
--pushOperand(y);
--pushOperand(x);
--pushOperator("<=");

Variable Index

o vSaveExecutionStack
This instance variable will hold the reference to a vector, which
in this case is the execution stack.

Constructor Index

o LogicalOperation(int)
This is the constructor for the logical operation.

Method Index

o append(LogicalOperation)
Method Name: append
Purpose: This method is used to append two logical operations together.
o execute()
Method Name: execute
Purpose: This method will execute this logical operation.
o executeStack()
MethodName: executeStack()
Purpose: This method is called after the execution stack has been loaded.
o getExecutionResult()
MethodName: getExecutionResult()
Purpose: This method is called after the execution stack has been executed.
o pushOperand(boolean)
Method Name: pushOperand
Purpose: This method will push an integer operand onto the
execution stack.
o pushOperand(Calculation)
Method Name: pushOperand
Purpose: This method will push a Calculation operand onto the
execution stack.
o pushOperand(double)
Method Name: pushOperand
Purpose: This method will push a double operand onto the
execution stack.
o pushOperand(float)
Method Name: pushOperand
Purpose: This method will push a float operand onto the
execution stack.
o pushOperand(int)
Method Name: pushOperand
Purpose: This method will push an integer operand onto the
execution stack.
o pushOperand(long)
Method Name: pushOperand
Purpose: This method will push long integer operand onto the
execution stack.
o pushOperand(String)
Method Name: pushOperand
Purpose: This method will push an integer operand onto the
execution stack.
o pushOperator(String[])
Method Name: pushOperator
Purpose: This method will receive a String dictating the operator
to push on the stack.
o removeOperand()
Method Name: removeOperand
Purpose: This method will remove the top-most operand from the
execution stack.
o removeOperator()
Method Name: removeOperator
Purpose: This method will remove the top-most operator from the
execution stack.
o removeTopMostElement()
Method Name: removeTopMostElement
Purpose: This method will remove the top-most element, regardless if it is
an operand or operator.

Variables

o vSaveExecutionStack 
 protected Vector vSaveExecutionStack
This instance variable will hold the reference to a vector, which
in this case is the execution stack.

Constructors

o LogicalOperation 
 public LogicalOperation(int iExecutionStackSize)
This is the constructor for the logical operation. It simply allocates
all instance data (i.e. the stack) and awaits for something to input.

Methods

o pushOperand 
 public void pushOperand(boolean booOperand)
Method Name: pushOperand
Purpose: This method will push an integer operand onto the
execution stack.
PRE: Nothing.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the execution stack must be one more than
it was before the insertion.

o pushOperand 
 public void pushOperand(int intOperand)
Method Name: pushOperand
Purpose: This method will push an integer operand onto the
execution stack.
PRE: Nothing.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the execution stack must be one more than
it was before the insertion.

o pushOperand 
 public void pushOperand(long longOperand)
Method Name: pushOperand
Purpose: This method will push long integer operand onto the
execution stack.
PRE: Nothing.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the stack must be one more than
it was before the insertion.

o pushOperand 
 public void pushOperand(float floatOperand)
Method Name: pushOperand
Purpose: This method will push a float operand onto the
execution stack.
PRE: Nothing.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the stack must be one more than
it was before the insertion.

o pushOperand 
 public void pushOperand(double doubleOperand)
Method Name: pushOperand
Purpose: This method will push a double operand onto the
execution stack.
PRE: Nothing.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the stack must be one more than
it was before the insertion.

o pushOperand 
 public void pushOperand(String stringOperand)
Method Name: pushOperand
Purpose: This method will push an integer operand onto the
execution stack.
PRE: Valid database variable.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the stack must be one more than
it was before the insertion.

o pushOperand 
 public void pushOperand(Calculation calcOperand)
Method Name: pushOperand
Purpose: This method will push a Calculation operand onto the
execution stack.
PRE: Nothing.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the stack must be one more than
it was before the insertion.

o pushOperator 
 public boolean pushOperator(String operatorNameAndParameterTypes[])
Method Name: pushOperator
Purpose: This method will receive a String dictating the operator
to push on the stack. Operators will be selected from an UI, which
is sort of a trusted source. Operators will be checked for validity and
compliance with supported boolean operators. Supported logical operators
are "<=", "<", ">=", ">", "!=".
PRE: operator must be one of the defined operators.
POST: Stack must not be empty, the last object placed is the one
passed a a parameter. The size of the stack must be one more than
it was before the insertion.

o removeOperand 
 public void removeOperand()
Method Name: removeOperand
Purpose: This method will remove the top-most operand from the
execution stack.
PRE: The top object in the execution stack must be an operand (of type
PushableOperand.
POST: The size of the execution stack must be one less than it was.

o removeOperator 
 public void removeOperator()
Method Name: removeOperator
Purpose: This method will remove the top-most operator from the
execution stack.
PRE: The top object in the execution stack must be an operator (of
type String) and a valid operator.
POST: The size of the execution stack must be one less than it was.

o removeTopMostElement 
 public void removeTopMostElement()
Method Name: removeTopMostElement
Purpose: This method will remove the top-most element, regardless if it is
an operand or operator.
PRE: The execution stack must not be empty.
POST: Nothing

o execute 
 public boolean execute()
Method Name: execute
Purpose: This method will execute this logical operation. The result
will be on the execution stack, accessible by getExecutionResult().
PRE: Stack is not empty.
POST: Result is the top-most element of the stack. The result is the
only element on the execution stack.

o executeStack 
 public boolean executeStack()
MethodName: executeStack()
Purpose: This method is called after the execution stack has been loaded.
This execution stack assumes operators/operands have been loaded onto the
execution stack in a RPN format.
PRE: Stack not empty.
POST: Result is the top-most element of the stack. The result is the
only element on the execution stack.

o getExecutionResult 
 public Boolean getExecutionResult()
MethodName: getExecutionResult()
Purpose: This method is called after the execution stack has been executed.
PRE: Only one element on the execution stack. If the element is not a Number
null is returned.
POST: Execution stack empty

o append 
 public void append(LogicalOperation logicalOperationToAppend)
Method Name: append
Purpose: This method is used to append two logical operations together. The passed
parameter is appended to the object owning the append call.
PRE: logicalOperationToAppend must not be null.
POST: The two logical operations are appended. 

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