de.congrace.exp4j
Class ExpressionBuilder

java.lang.Object
  de.congrace.exp4j.ExpressionBuilder

public class ExpressionBuilder
extends Object

This is a Builder implementation for the exp4j API used to create a Calculable instance for the user

Author:

frank asseg

Field Summary

static String

PROPERTY_UNARY_HIGH_PRECEDENCE Property name for unary precedence choice.

Constructor Summary

ExpressionBuilder(String expression)
Create a new ExpressionBuilder

Method Summary

Calculable	build() build a new Calculable from the expression using the supplied variables
ExpressionBuilder	withCustomFunction(CustomFunction function) add a custom function instance for the evaluator to recognize
ExpressionBuilder	withCustomFunctions(Collection<CustomFunction> functions)
ExpressionBuilder	withExpression(String expression) set the mathematical expression for parsing
ExpressionBuilder	withOperation(CustomOperator operation) set a CustomOperator to be used in the expression
ExpressionBuilder	withOperations(Collection<CustomOperator> operations) set a Collection of CustomOperator to use in the expression
ExpressionBuilder	withVariable(String variableName, double value) set the value for a variable
ExpressionBuilder	withVariableNames(String... variableNames) set the variables names used in the expression without setting their values
ExpressionBuilder	withVariables(Map<String,Double> variableMap) set the values for variables

Methods inherited from class java.lang.Object

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

Field Detail

PROPERTY_UNARY_HIGH_PRECEDENCE

public static final String PROPERTY_UNARY_HIGH_PRECEDENCE

Property name for unary precedence choice. You can set System.getProperty(PROPERTY_UNARY_HIGH_PRECEDENCE,"false") in order to change evaluation from an expression like "-3^2" from "(-3)^2" to "-(3^2)"

See Also:

Constant Field Values

Constructor Detail

ExpressionBuilder

public ExpressionBuilder(String expression)

Create a new ExpressionBuilder

Parameters:

expression - the expression to evaluate

Method Detail

build

public Calculable build()
                 throws UnknownFunctionException,
                        UnparsableExpressionException

build a new Calculable from the expression using the supplied variables

Returns:

the Calculable which can be used to evaluate the expression

Throws:

UnknownFunctionException - when an unrecognized function name is used in the expression

UnparsableExpressionException - if the expression could not be parsed

withCustomFunction

public ExpressionBuilder withCustomFunction(CustomFunction function)

add a custom function instance for the evaluator to recognize

Parameters:

function - the CustomFunction to add

Returns:

the ExpressionBuilder instance

withCustomFunctions

public ExpressionBuilder withCustomFunctions(Collection<CustomFunction> functions)

withVariable

public ExpressionBuilder withVariable(String variableName,
                                      double value)

set the value for a variable

Parameters:

variableName - the variable name e.g. "x"

value - the value e.g. 2.32d

Returns:

the ExpressionBuilder instance

withVariableNames

public ExpressionBuilder withVariableNames(String... variableNames)

set the variables names used in the expression without setting their values

Parameters:

variableNames - vararg String of the variable names used in the expression

Returns:

the ExpressionBuilder instance

withVariables

public ExpressionBuilder withVariables(Map<String,Double> variableMap)

set the values for variables

Parameters:

variableMap - a map of variable names to variable values

Returns:

the ExpressionBuilder instance

withOperation

public ExpressionBuilder withOperation(CustomOperator operation)

set a CustomOperator to be used in the expression

Parameters:

operation - the CustomOperator to be used

Returns:

the ExpressionBuilder instance

withOperations

public ExpressionBuilder withOperations(Collection<CustomOperator> operations)

set a Collection of CustomOperator to use in the expression

Parameters:

operations - the Collection of CustomOperator to use

Returns:

the ExpressionBuilder instance

withExpression

public ExpressionBuilder withExpression(String expression)

set the mathematical expression for parsing

Parameters:

expression - a mathematical expression

Returns:

the ExpressionBuilder instance