Package com.singularsys.jep.functions

Class NaryBinaryFunction

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.NaryBinaryFunction

All Implemented Interfaces:

PostfixMathCommandI, Serializable

Direct Known Subclasses:

Add, Concat, JepTest.MyNaryBinary, Multiply, NullWrapTest.MyNaryBinary

public abstract class NaryBinaryFunction
extends PostfixMathCommand

Convenient base class for n-ary functions backed by a binary operation. Defines an Object eval(Object l,Object r) method for calculating the result. The operation must be associative.

Author:

Richard Morris

See Also:

• Serialized Form

Field Summary

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, description, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
NaryBinaryFunction()

Method Summary

Modifier and Type	Method	Description
boolean	checkNumberOfParameters(int n)	Checks the number of parameters of the function.
Object	eval(Object[] args)	Evaluate given an array of arguments.
abstract Object	eval(Object l, Object r)	Evaluate given a pair of arguments.
static NaryBinaryFunction	instanceOf(BinaryFunction.BiFunctionWithException<Object> fun)	Create a NaryBinaryFunction from a lambda expression where arguments can be Objects.
static NaryBinaryFunction	instanceOf(BinaryFunction.BiFunctionWithException<Object> fun, String name)	Create a named NaryBinaryFunction from a lambda expression where arguments can be Objects.
static <T> NaryBinaryFunction	instanceOf(Class<T> type, BinaryFunction.BiFunctionWithException<T> fun)	Create a NaryBinaryFunction from a lambda expression where both arguments are of a specified type.
static <T> NaryBinaryFunction	instanceOf(Class<T> type, BinaryFunction.BiFunctionWithException<T> fun, String name)	Create a NaryBinaryFunction from a lambda expression where both arguments are of a specified type.
void	run(Stack<Object> stack)	Calls eval(Object, Object)

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, asType, getDescription, getDescription, getDescriptionWithType, getName, getNumberOfParameters, setCurNumberOfParameters, setDescription, setName, toString, toString

Methods inherited from class java.lang.Object

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

Constructor Details

NaryBinaryFunction

public NaryBinaryFunction()

Method Details

checkNumberOfParameters

public boolean checkNumberOfParameters(int n)

Description copied from class: PostfixMathCommand

Checks the number of parameters of the function. Functions which set numberOfParameter=-1 should overload this method

Specified by:

checkNumberOfParameters in interface PostfixMathCommandI

Overrides:

checkNumberOfParameters in class PostfixMathCommand

Parameters:

n - number of parameters function will be called with.

Returns:

false if an illegal number of parameters is supplied, true otherwise.

run

public void run(Stack<Object> stack)
         throws EvaluationException

Calls eval(Object, Object)

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class PostfixMathCommand

Parameters:

stack - arguments for function

Throws:

EvaluationException - if function cannot be evaluated

eval

public Object eval(Object[] args)
            throws EvaluationException

Evaluate given an array of arguments. Calls the eval(Object, Object) method for the first pair of arguments, then repeatedly with the current result and the next argument.

Parameters:

args - array of arguments to function, must have at least one element

Returns:

result of function

Throws:

EvaluationException - if empty array

eval

public abstract Object eval(Object l,
 Object r)
                     throws EvaluationException

Evaluate given a pair of arguments. Must be specified for all implementing classes.

Parameters:

l - lhs argument

r - rhs argument

Returns:

result of applying the function to the arguments

Throws:

EvaluationException - on error.

instanceOf

public static NaryBinaryFunction instanceOf(BinaryFunction.BiFunctionWithException<Object> fun)

Create a NaryBinaryFunction from a lambda expression where arguments can be Objects. For example NaryBinaryFunction.instanceOf((x,y) -> ((Number) x).doubleValue() + ((Number) y).doubleValue())

Parameters:

fun - the lambda function

Returns:

a new NaryBinaryFunction instance

Since:

Jep 4.0

instanceOf

public static NaryBinaryFunction instanceOf(BinaryFunction.BiFunctionWithException<Object> fun,
 String name)

Create a named NaryBinaryFunction from a lambda expression where arguments can be Objects. For example NaryBinaryFunction.instanceOf((x,y) -> ((Number) x).doubleValue() + ((Number) y).doubleValue())

Parameters:

fun - the lambda function

Returns:

a new NaryBinaryFunction instance

Since:

Jep 4.0

instanceOf

public static <T> NaryBinaryFunction instanceOf(Class<T> type,
 BinaryFunction.BiFunctionWithException<T> fun)

Create a NaryBinaryFunction from a lambda expression where both arguments are of a specified type. For example NaryBinaryFunction.instanceOf(Integer.class, (x,y) -> x * y) The eval(Object[]) and eval(Object, Object) will throw an IllegalParameterException if any argument is not of the correct type.

Type Parameters:

T - type of arguments and return value

Parameters:

type - type of the arguments

fun - the lambda function

Returns:

a new NaryBinaryFunction instance

Since:

Jep 4.0

instanceOf

public static <T> NaryBinaryFunction instanceOf(Class<T> type,
 BinaryFunction.BiFunctionWithException<T> fun,
 String name)

Create a NaryBinaryFunction from a lambda expression where both arguments are of a specified type. For example NaryBinaryFunction.instanceOf(Integer.class, (x,y) -> x * y) The eval(Object[]) and eval(Object, Object) will throw an IllegalParameterException if any argument is not of the correct type.

Type Parameters:

T - type of arguments and return value

Parameters:

type - type of the arguments

fun - the lambda function

Returns:

a new NaryBinaryFunction instance

Since:

Jep 4.0