Package com.singularsys.jep.functions

Class ArrayFunctionBase

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.ArrayFunctionBase

All Implemented Interfaces:

ZeroLengthBehaviourI, PostfixMathCommandI, Serializable

Direct Known Subclasses:

Average, BigDecVSum, ElementOf, MinMax, VSum

public abstract class ArrayFunctionBase
extends PostfixMathCommand
implements ZeroLengthBehaviourI

Base class for functions that operate on arrays such as Average, MinMax, and VSum. The shared functionality such as array flattening is implemented here. In the run() method, before calling calc(), Vectors and nested Vectors are flattened so 1,[2,[3, 4]] becomes [1, 2, 3, 4] which is passed in to the calc method as a List<Object>.

Since:

3.4.0

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.singularsys.jep.functions.ZeroLengthBehaviourI

ZeroLengthBehaviourI.DefaultZeroLengthBehaviourI, ZeroLengthBehaviourI.ZeroLengthErrorBehaviour, ZeroLengthBehaviourI.ZeroLengthHelper

Field Summary

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

curNumberOfParameters, description, name, NaN, numberOfParameters

Constructor Summary

Constructors

Modifier	Constructor	Description
	ArrayFunctionBase()	Default the number of parameters to any number of params (-1).
protected	ArrayFunctionBase(ZeroLengthBehaviourI.ZeroLengthErrorBehaviour zeroLengthErrorBehaviour)	Constructor with a specified zero length error behaviour.
protected	ArrayFunctionBase(Object zeroLengthValue)	Constructor with a specified value to return for zero length arrays.

Method Summary

Modifier and Type	Method	Description
protected void	addToArray(List<Object> l, Object val)	Adds a value val to the array l.
protected abstract Object	calc(List<Object> l)	Abstract method for performing the array calculation.
boolean	checkNumberOfParameters(int n)	Must have one or more parameter
ZeroLengthBehaviourI.ZeroLengthErrorBehaviour	getZeroLengthErrorBehaviour()	Gets how to respond to arguments with zero length arrays.
Object	getZeroLengthValue()	Gets the value to be returned when a zero length array is passed as an argument and the zero length error behaviour is set to VALUE.
void	run(Stack<Object> stack)	Calls the calc method after concatenating all elements into list.
void	setZeroLengthErrorBehaviour(ZeroLengthBehaviourI.ZeroLengthErrorBehaviour zeroLengthErrorBehaviour)	Sets how to respond to arguments with zero length arrays.
void	setZeroLengthValue(Object zeroLengthValue)	Sets the value to be returned when a zero length array is passed and the zero length error behaviour is set to VALUE.
protected void	throwAtLeastOneExcep()	Throws an exception indicating that at least one argument is required.

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

Methods inherited from interface com.singularsys.jep.functions.ZeroLengthBehaviourI

getErrorMessage, getValueOrException, zeroLengthResultOrException

Constructor Details

ArrayFunctionBase

public ArrayFunctionBase()

Default the number of parameters to any number of params (-1).

ArrayFunctionBase

protected ArrayFunctionBase(ZeroLengthBehaviourI.ZeroLengthErrorBehaviour zeroLengthErrorBehaviour)

Constructor with a specified zero length error behaviour.

Parameters:

zeroLengthErrorBehaviour -

ArrayFunctionBase

protected ArrayFunctionBase(Object zeroLengthValue)

Constructor with a specified value to return for zero length arrays. Sets the zero length error behaviour to VALUE.

Parameters:

zeroLengthValue - the value to return when a zero length array is passed

Method Details

checkNumberOfParameters

public boolean checkNumberOfParameters(int n)

Must have one or more parameter

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 the calc method after concatenating all elements into list. Subclasses are responsible for implementing the calc method and handling the zero length array case.

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class PostfixMathCommand

Parameters:

stack - arguments for function

Throws:

EvaluationException - if function cannot be evaluated

addToArray

protected void addToArray(List<Object> l,
 Object val)

Adds a value val to the array l. This method flattens Vectors and nested Vectors so 1,[2,[3, 4]] becomes [1, 2, 3, 4].

Parameters:

l - The list to which to add a.

val - The value to be added (can be a Vector).

calc

protected abstract Object calc(List<Object> l)
                        throws EvaluationException

Abstract method for performing the array calculation.

Parameters:

l - The list to operate on. Note this is in reverse order of the arguments of the function.

Returns:

The result of the calculation.

Throws:

EvaluationException - if the calculation cannot be performed

throwAtLeastOneExcep

protected void throwAtLeastOneExcep()
                             throws EvaluationException

Throws an exception indicating that at least one argument is required.

Throws:

EvaluationException

getZeroLengthErrorBehaviour

public ZeroLengthBehaviourI.ZeroLengthErrorBehaviour getZeroLengthErrorBehaviour()

Description copied from interface: ZeroLengthBehaviourI

Gets how to respond to arguments with zero length arrays.

Specified by:

getZeroLengthErrorBehaviour in interface ZeroLengthBehaviourI

Returns:

either EXCEPTION, NAN or VALUE

setZeroLengthErrorBehaviour

public void setZeroLengthErrorBehaviour(ZeroLengthBehaviourI.ZeroLengthErrorBehaviour zeroLengthErrorBehaviour)

Description copied from interface: ZeroLengthBehaviourI

Sets how to respond to arguments with zero length arrays. Either an Exception is thrown or NaN is returned.

Specified by:

setZeroLengthErrorBehaviour in interface ZeroLengthBehaviourI

Parameters:

zeroLengthErrorBehaviour - either EXCEPTION, NAN or VALUE

getZeroLengthValue

public Object getZeroLengthValue()

Description copied from interface: ZeroLengthBehaviourI

Gets the value to be returned when a zero length array is passed as an argument and the zero length error behaviour is set to VALUE.

Specified by:

getZeroLengthValue in interface ZeroLengthBehaviourI

Returns:

the value, null by default

setZeroLengthValue

public void setZeroLengthValue(Object zeroLengthValue)

Description copied from interface: ZeroLengthBehaviourI

Sets the value to be returned when a zero length array is passed and the zero length error behaviour is set to VALUE. The ZeroLengthBehaviourI.setZeroLengthErrorBehaviour(ZeroLengthErrorBehaviour) method should be used to set the zero length error behaviour to VALUE.

Specified by:

setZeroLengthValue in interface ZeroLengthBehaviourI

Parameters:

zeroLengthValue - the value to return when a zero length array is passed