org.safs.SafsExpression
Class SafsExpression

java.lang.Object
  |
  +--org.safs.SafsExpression.SafsExpression

public class SafsExpression

extends java.lang.Object

Field Summary

protected boolean	booErrors
protected boolean	debugPrint
protected java.util.Hashtable	hSafsVars
protected int	iExpressionlength
protected int	numDecimalPlaces
protected java.lang.String	sExpression
protected java.lang.String	strErrors
protected boolean	stripLeadZero
protected boolean	stripTrailingDecimalPoint
protected boolean	stripTrailingZeros
protected java.util.Vector	vQuoteLocs
protected java.util.Vector	vSubStrings
protected java.util.Vector	vVariableNames

Constructor Summary

SafsExpression(java.lang.String sText)
Method SafsExpression.

Method Summary

protected java.lang.String	dereferenceVariable(java.lang.String strText) Method dereferenceVariable.
java.lang.String	evalExpression() Method evalExpression.
protected java.lang.String	evalExpression(java.lang.String strExpr) Method evalExpression.
protected java.lang.String	evalPrimative(java.lang.String strLeftOperand, java.lang.String strOperator, java.lang.String strRightOperand) Method evalPrimative.
protected java.lang.String	evalSimple(java.lang.String strExpr) Method evalSimple.
java.lang.String	getExpression() Method getExpression.
protected java.lang.String	getLeftOperand(java.lang.String strExpr, int iOperatorLoc) Method getLeftOperand.
java.util.Vector	getQuoteLocs() Method getQuoteLocs.
protected java.lang.String	getRightOperand(java.lang.String strExpr, int iOperatorLoc) Method getRightOperand.
java.util.Vector	getSubStrings() Method getSubStrings.
java.util.Hashtable	getVarHash()
java.util.Vector	getVariableNames() Method getVariableNames.
protected java.lang.String	getVarValue(java.lang.String strVarName) Method getVarValue.
protected java.lang.String	handleOperators(java.lang.String strExpr, java.lang.String strOps) Method handleOperators.
protected void	initData(java.lang.String sText) Method initData.
int	numDecimalPlaces() Method numDecimalPlaces.
void	numDecimalPlaces(int i) Method numDecimalPlaces.
void	setExpression(java.lang.String sText) Method setExpression.
void	setVarHash(java.util.Hashtable h)
protected void	setVariableNames() Method setVariableNames.
protected void	setVarValue(java.lang.String strVarName, java.lang.String strVarValue) Method setVarValue.
boolean	stripLeadZero() Method stripLeadZero.
void	stripLeadZero(boolean b) Method stripLeadZero.
boolean	stripTrailingDecimalPoint() Method stripTrailingDecimalPoint.
void	stripTrailingDecimalPoint(boolean b) Method stripTrailingDecimalPoint.
boolean	stripTrailingZeros() Method stripTrailingZeros.
void	stripTrailingZeros(boolean b) Method stripTrailingZeros.
protected boolean	validateParens() Method validateParens.
protected void	validateVariableNames() Method validateVariableNames.

Methods inherited from class java.lang.Object

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

Field Detail

sExpression

protected java.lang.String sExpression

iExpressionlength

protected int iExpressionlength

vQuoteLocs

protected java.util.Vector vQuoteLocs

vSubStrings

protected java.util.Vector vSubStrings

vVariableNames

protected java.util.Vector vVariableNames

strErrors

protected java.lang.String strErrors

booErrors

protected boolean booErrors

debugPrint

protected boolean debugPrint

stripLeadZero

protected boolean stripLeadZero

stripTrailingZeros

protected boolean stripTrailingZeros

stripTrailingDecimalPoint

protected boolean stripTrailingDecimalPoint

numDecimalPlaces

protected int numDecimalPlaces

hSafsVars

protected java.util.Hashtable hSafsVars

Constructor Detail

SafsExpression

public SafsExpression(java.lang.String sText)
               throws java.lang.Exception

Method SafsExpression.

Parameters:

sText - The SAFS string expression

Throws:

java.lang.Exception - Error messages such as unmatched parentheses or illegal variable names

Method Detail

setExpression

public void setExpression(java.lang.String sText)
                   throws java.lang.Exception

Method setExpression. Sets the SAFS expression to a new value and initializes internals

Parameters:

sText - The SAFS string expression

Throws:

java.lang.Exception - Error messages such as unmatched parentheses or illegal variable names

getExpression

public java.lang.String getExpression()

Method getExpression. Accessor for the protected field sExpression

Returns:

String The SAFS expression

getQuoteLocs

public java.util.Vector getQuoteLocs()

Method getQuoteLocs. Accessor for the protected field vQuoteLocs

Returns:

Vector Integer objects containing locations of the quotes (if any)

getSubStrings

public java.util.Vector getSubStrings()

Method getSubStrings. Accessor for the protected field vSubStrings

Returns:

Vector String objects containing quoted substrings of the expression (if any)

getVariableNames

public java.util.Vector getVariableNames()

Method getVariableNames. Accessor for the protected field vVariableNames

Returns:

Vector String objects that are the variables found within the expression sExpression

stripLeadZero

public void stripLeadZero(boolean b)

Method stripLeadZero. Setter for the protected field stripLeadZero

sets option to strip the leading zero from expression results. For example, if the expression evaluates to 0.1 and stripLeadZero is true, the result will be formatted such that the leading zero is not shown, which would be .1

Parameters:

b - true or false specifying wheather or not leading zeros should be stripped

stripLeadZero

public boolean stripLeadZero()

Method stripLeadZero. Accessor for the protected field stripLeadZero

Returns:

boolean The current specified option to strip leading zeros

stripTrailingZeros

public void stripTrailingZeros(boolean b)

Method stripTrailingZeros. Setter for the protected field stripTrailingZeros

sets option to strip the trailing zeros from expression results. For example, if the expression evaluates to 1.100 and stripTrailingZeros is true, the result will be formatted such that the trailing zeros are not shown, which would be 1.1

Parameters:

b - true or false specifying wheather or not trailing zeros should be stripped

stripTrailingZeros

public boolean stripTrailingZeros()

Method stripTrailingZeros. Accessor for the protected field stripTrailingZeros

Returns:

boolean The current specified option to strip trailing zeros

stripTrailingDecimalPoint

public void stripTrailingDecimalPoint(boolean b)

Method stripTrailingDecimalPoint. Setter for the protected field stripTrailingDecimalPoint

sets option to strip the trailing decimal points from expression results. For example, if the expression evaluates to 1. and stripTrailingDecimalPoint is true, the result will be formatted such that the trailing zeros are not shown, which would be 1

Parameters:

b - true or false specifying wheather or not trailing decimal points should be stripped

stripTrailingDecimalPoint

public boolean stripTrailingDecimalPoint()

Method stripTrailingDecimalPoint. Accessor for the protected field stripTrailingDecimalPoint

Returns:

boolean The current specified option to strip trailing decimal point

numDecimalPlaces

public void numDecimalPlaces(int i)

Method numDecimalPlaces. Setter for the protected field numDecimalPlaces

Parameters:

i - int specifying the number of decimal places to round half up in division operations

numDecimalPlaces

public int numDecimalPlaces()

Method numDecimalPlaces. Accessor for the protected field numDecimalPlaces

Returns:

int The number of decimal places to round half up in division operations

evalExpression

public java.lang.String evalExpression()

Method evalExpression. This is the method called to evaluate the expression and return the result

Returns:

String The result of evaluating the expression

initData

protected void initData(java.lang.String sText)
                 throws java.lang.Exception

Method initData. Initialize internal data fields and validate the expression

Parameters:

sText - The SAFS string expression

Throws:

java.lang.Exception - Error messages such as unmatched parentheses or illegal variable names

setVariableNames

protected void setVariableNames()

Method setVariableNames. Used to populate the protected field vVariableNames

validateParens

protected boolean validateParens()

Method validateParens. Returns true or false specifying wheather or not the expression has correctly matched parentheses

Returns:

boolean

validateVariableNames

protected void validateVariableNames()

Method validateVariableNames. Make sure the variables within the expression are legally named. Set error string and flag for illegally named variables.

getVarValue

protected java.lang.String getVarValue(java.lang.String strVarName)

Method getVarValue. Retrieve the SAFS variable value

Parameters:

strVarName - The name of the variable to retrieve

Returns:

String The value of the variable

setVarValue

protected void setVarValue(java.lang.String strVarName,
                           java.lang.String strVarValue)

Method setVarValue. Set the specified variable to the specified value

Parameters:

strVarName - The name of the variable to set

strVarValue - The value to set the variable to

evalExpression

protected java.lang.String evalExpression(java.lang.String strExpr)

Method evalExpression. Recursively called with each nested parenthetical expression

Parameters:

strExpr - The expression to evaluate

Returns:

String The result of the evaluation

evalSimple

protected java.lang.String evalSimple(java.lang.String strExpr)

Method evalSimple. A simple expression is one without parentheses

Parameters:

strExpr - The simple expression to evaluate

Returns:

String The simple expression evaluated

handleOperators

protected java.lang.String handleOperators(java.lang.String strExpr,
                                           java.lang.String strOps)

Method handleOperators. The grunt work of handling operators at the same precedence.

Parameters:

strExpr - The expression to evaluate

strOps - The operators to handle at the same precedence. For example "+-&" are evaluated at the same precedence.

Returns:

String The result of the expression evaluation

dereferenceVariable

protected java.lang.String dereferenceVariable(java.lang.String strText)

Method dereferenceVariable. If strText is a variable, return its value

Parameters:

strText - The string to check wich may or may not be a variable

Returns:

String The string strText or the value of the variable if strText is a variable

getRightOperand

protected java.lang.String getRightOperand(java.lang.String strExpr,
                                           int iOperatorLoc)

Method getRightOperand. Using infix notation, the right operand is the string to the right of the operator at iOperatorLoc up to a termination character.

Parameters:

strExpr - The expression

iOperatorLoc - The int location of the operator within strExpr

Returns:

String The right operand

getLeftOperand

protected java.lang.String getLeftOperand(java.lang.String strExpr,
                                          int iOperatorLoc)

Method getLeftOperand. Using infix notation, the left operand is the string to the left of the operator at iOperatorLoc up to a termination character.

Parameters:

strExpr - The expression

iOperatorLoc - The int location of the operator within strExpr

Returns:

String The left operand

evalPrimative

protected java.lang.String evalPrimative(java.lang.String strLeftOperand,
                                         java.lang.String strOperator,
                                         java.lang.String strRightOperand)

Method evalPrimative. Primative means an expression in infix notation as "LeftOperand Operator RightOperand" only

Parameters:

strLeftOperand - The left operand

strOperator - The operator

strRightOperand - The right operand

Returns:

String The result of evaluating "LeftOperand Operator RightOperand"

setVarHash

public void setVarHash(java.util.Hashtable h)

getVarHash

public java.util.Hashtable getVarHash()