synergynet3.web.apps.numbernet.expressionevaluator

Class MathEvaluator

java.lang.Object

synergynet3.web.apps.numbernet.expressionevaluator.MathEvaluator

public class MathEvaluator
extends java.lang.Object

Mathematic expression evaluator. Supports the following functions: +, -, *, /, ^, %, cos, sin, tan, acos, asin, atan, sqrt, sqr, log, min, max, ceil, floor, abs, neg, rndr.
When the getValue() is called, a Double object is returned. If it returns null, an error occured.

 Sample:
 MathEvaluator m = new MathEvaluator("-5-6/(-2) + sqr(15+x)");
 m.addVariable("x", 15.1d);
 System.out.println( m.getValue() );
 

Version:

1.1

Author:

The-Son LAI, Lts@writeme.com

Constructor Summary

Constructors

Constructor and Description
MathEvaluator() creates an empty MathEvaluator.
MathEvaluator(java.lang.String s) creates a MathEvaluator and assign the math expression string.

Method Summary

Methods

Modifier and Type	Method and Description
void	addVariable(java.lang.String v, double val) adds a variable and its value in the MathEvaluator
void	addVariable(java.lang.String v, java.lang.Double val) adds a variable and its value in the MathEvaluator
java.lang.Double	getValue() evaluates and returns the value of the expression
java.lang.Double	getVariable(java.lang.String s) gets the variable's value that was assigned previously
static void	main(java.lang.String[] args) Main.
void	reset() resets the evaluator
void	setExpression(java.lang.String s) sets the expression
void	trace() trace the binary tree for debug

Methods inherited from class java.lang.Object

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

Constructor Detail

MathEvaluator

public MathEvaluator()

creates an empty MathEvaluator. You need to use setExpression(String s) to assign a math expression string to it.

MathEvaluator

public MathEvaluator(java.lang.String s)

creates a MathEvaluator and assign the math expression string.

Method Detail

main

public static void main(java.lang.String[] args)

Main. To run the program in command line. Usage: java MathEvaluator.main [your math expression]

addVariable

public void addVariable(java.lang.String v,
               double val)

adds a variable and its value in the MathEvaluator

addVariable

public void addVariable(java.lang.String v,
               java.lang.Double val)

adds a variable and its value in the MathEvaluator

getValue

public java.lang.Double getValue()
                          throws java.lang.Exception

evaluates and returns the value of the expression

Throws:

java.lang.Exception

getVariable

public java.lang.Double getVariable(java.lang.String s)

gets the variable's value that was assigned previously

reset

public void reset()

resets the evaluator

setExpression

public void setExpression(java.lang.String s)

sets the expression

trace

public void trace()

trace the binary tree for debug