com.mpobjects.bdparsii.eval

Class UnaryFunction

java.lang.Object

com.mpobjects.bdparsii.eval.UnaryFunction

All Implemented Interfaces:

Function

public abstract class UnaryFunction
extends Object
implements Function

Represents an unary function.

An unary function has one arguments which is always evaluated in order to compute the final result.

Constructor Summary

Constructors

Constructor and Description
UnaryFunction()

Method Summary

Modifier and Type	Method and Description
protected abstract BigDecimal	eval(BigDecimal a, MathContext mathContext) Performs the computation of the unary function
BigDecimal	eval(List<Expression> args, MathContext mathContext) Executes the function with the given arguments.
int	getNumberOfArguments() Returns the number of expected arguments.
boolean	isNaturalFunction() A natural function returns the same output for the same input.

Methods inherited from class java.lang.Object

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

Constructor Detail

UnaryFunction

public UnaryFunction()

Method Detail

getNumberOfArguments

public int getNumberOfArguments()

Description copied from interface: Function

Returns the number of expected arguments.

If the function is called with a different number of arguments, an error will be created

In order to support functions with a variable number of arguments, a negative number can be returned. This will essentially disable the check.

Specified by:

getNumberOfArguments in interface Function

Returns:

the number of arguments expected by this function or a negative number to indicate that this function accepts a variable number of arguments

eval

public BigDecimal eval(List<Expression> args,
                       MathContext mathContext)

Description copied from interface: Function

Executes the function with the given arguments.

The arguments need to be evaluated first. This is not done externally to permit functions to perform lazy evaluations.

Specified by:

eval in interface Function

Parameters:

args - the arguments for this function. The length of the given list will exactly match getNumberOfArguments

mathContext - the math context to use.

Returns:

the result of the function evaluated with the given arguments

eval

protected abstract BigDecimal eval(BigDecimal a,
                                   MathContext mathContext)

Performs the computation of the unary function

Parameters:

a - the argument of the function

mathContext - the math context

Returns:

the result of calling the function with a as argument

isNaturalFunction

public boolean isNaturalFunction()

Description copied from interface: Function

A natural function returns the same output for the same input.

All classical mathematical functions are "natural". A function which reads user input is not natural, as the function might return different results depending on the users input

Specified by:

isNaturalFunction in interface Function

Returns:

true if the function returns the same output for the same input, false otherwise