com.interpss.dstab.datatype

Class ExpCalculator

java.lang.Object

com.interpss.dstab.datatype.ExpCalculator

public class ExpCalculator
extends java.lang.Object

An implementation for math expression evaluation An expression string (A+b*c-d/e) is first converted to a list of ExpCalculator.Rec. Then with an array of values [1.0, 2.0, 3.0, 4.0, 5.0], the eval() method is used to calculate the expression value.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ExpCalculator.Opt Expression operator type
static class	ExpCalculator.Rec The expression string is convert to a list of Rec.

Field Summary

Fields

Modifier and Type	Field and Description
static char	chAdd
static char	chDiv
static char	chMul
static char	chSub

Constructor Summary

Constructors

Constructor and Description
ExpCalculator(java.lang.String exp) Contructor for an expression calculator object

Method Summary

Modifier and Type	Method and Description
double	eval(double[] xAry) Evaluate the expression based on the input value arary.
ExpCalculator.Rec[]	getRecList() Get the expression component record list
boolean	hasField(java.lang.String fieldName) check if the expression has the field identified by the name
boolean	hasVarType(CMLVarEnum type) check if the expression has the var type
static boolean	isExpression(java.lang.String exp) Check if the string is an InterPSS expression
java.lang.String	toString() convert the object states to a string

Methods inherited from class java.lang.Object

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

Field Detail

chAdd

public static final char chAdd

See Also:

Constant Field Values

chSub

public static final char chSub

See Also:

Constant Field Values

chMul

public static final char chMul

See Also:

Constant Field Values

chDiv

public static final char chDiv

See Also:

Constant Field Values

Constructor Detail

ExpCalculator

public ExpCalculator(java.lang.String exp)
              throws InterpssException

Contructor for an expression calculator object

Parameters:

exp - the expression string

Throws:

java.lang.Exception - exception if the format is wrong

InterpssException

Method Detail

isExpression

public static boolean isExpression(java.lang.String exp)

Check if the string is an InterPSS expression

Parameters:

exp -

Returns:

getRecList

public ExpCalculator.Rec[] getRecList()

Get the expression component record list

Returns:

eval

public double eval(double[] xAry)
            throws InterpssException

Evaluate the expression based on the input value arary. For "A+b+c" and [1,2,3], the result should be 6.

Parameters:

xAry - the vaule array

Returns:

the expression value

Throws:

java.lang.Exception - when the value array has worng diamension

InterpssException

hasVarType

public boolean hasVarType(CMLVarEnum type)

check if the expression has the var type

hasField

public boolean hasField(java.lang.String fieldName)

check if the expression has the field identified by the name

Parameters:

fieldName -

Returns:

toString

public java.lang.String toString()

convert the object states to a string

Overrides:

toString in class java.lang.Object