edu.hws.jcm.functions
Class WrapperFunction

java.lang.Object
  |
  +--edu.hws.jcm.functions.FunctionParserExtension
        |
        +--edu.hws.jcm.functions.WrapperFunction

All Implemented Interfaces:

ExpressionCommand, Function, MathObject, ParserExtension, java.io.Serializable

public class WrapperFunction

extends FunctionParserExtension

A WrapperFunction contains another function and delegates to it all calls to methods from the Function interface, except for calls to setName() and getName(). (It maintains its own name, which can be different from the name of the wrapped Function.) This has at least two uses: A WrapperFunction is a FunctionParserExtension, so it can be added to a parser and then used in expressions parsed in that parser. Second, the function that is wrapped inside the WrapperFunction object can be changed by a call to the setFunction() method. This makes it possible to have a single function that can be used, for example, in ValueMath objects and Graph1D's, whose definition can be changed at will. Note that it is NOT legal to change the arity of the function when calling the setFunction() method.

See Also:

Serialized Form

Fields inherited from class edu.hws.jcm.functions.FunctionParserExtension

name

Constructor Summary

WrapperFunction(Function f)
Create a WrapperFunction object containing a specified function.

Method Summary

void	apply(StackOfDouble stack, Cases cases) Evaluate the function applied to argument values popped from the stack, and leave the result on the stack.
boolean	dependsOn(Variable x) Return true if the definition of this function depends in some way on the variable x.
Function	derivative(int wrt) Return the derivative of the function with repect to argument number wrt, where arguments are numbered starting from 1.
Function	derivative(Variable x) Return the derivative of the function with respect to the variable x (where x is NOT one of the parameters of the function).
int	getArity() Return the number of arguments of this function.
Function	getFunction() Return the function that is currently wrapped in this WrapperFunction.
double	getVal(double[] arguments) Find the value of the function at the argument value argument[0], ....
double	getValueWithCases(double[] arguments, Cases cases) Find the value of the function at the argument values argument[0],....
void	setFunction(Function f) Set the function that is contained in this WrapperFunction.

Methods inherited from class edu.hws.jcm.functions.FunctionParserExtension

appendOutputString, compileDerivative, doParse, extent, getName, setName, setParensCanBeOptional

Methods inherited from class java.lang.Object

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

Constructor Detail

WrapperFunction

public WrapperFunction(Function f)

Create a WrapperFunction object containing a specified function.

Parameters:

f - The non-null function that will be contained in the WrapperFunction.

Method Detail

setFunction

public void setFunction(Function f)

Set the function that is contained in this WrapperFunction.

Parameters:

f - The non-null function to be used in this WrapperFunction object. It must have the same arity as the current function.

getFunction

public Function getFunction()

Return the function that is currently wrapped in this WrapperFunction.

getArity

public int getArity()

Return the number of arguments of this function.

getVal

public double getVal(double[] arguments)

Find the value of the function at the argument value argument[0], .... The number of arguments should match the arity of the function.

getValueWithCases

public double getValueWithCases(double[] arguments,
                                Cases cases)

Find the value of the function at the argument values argument[0],.... Information about "cases" is stored in the Cases parameter, if it is non-null. See the Cases class for more information.

derivative

public Function derivative(int wrt)

Return the derivative of the function with repect to argument number wrt, where arguments are numbered starting from 1.

derivative

public Function derivative(Variable x)

Return the derivative of the function with respect to the variable x (where x is NOT one of the parameters of the function).

dependsOn

public boolean dependsOn(Variable x)

Return true if the definition of this function depends in some way on the variable x. (Note that the function does NOT depend on the variables that are being used as its parameters!)

apply

public void apply(StackOfDouble stack,
                  Cases cases)

Evaluate the function applied to argument values popped from the stack, and leave the result on the stack. This is not meant to be called directly.

Overrides:

apply in class FunctionParserExtension

Following copied from interface: edu.hws.jcm.data.ExpressionCommand

Parameters:

stack - contains results of previous commands in the program.

cases - if non-null, any case information generated during evaluation should be recorded here.