Package com.singularsys.jep.misc.functions

Class ElementOf

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.ArrayFunctionBase

com.singularsys.jep.misc.functions.ElementOf

All Implemented Interfaces:

PostfixMathCommandI, Serializable

public class ElementOf
extends ArrayFunctionBase

Tests if the first argument is in a set of values given in subsequent arguments. For example IN(var,"north","south","east","west"). An array can be used for a two argument version IN(var,["north","south","east","west"]). The function can be configured to return the negation, i.e. not element of.

The function could be used as an operator:

 public enum InOperators implements EmptyOperatorTable.OperatorKey {
      IN,NOTIN
 }
 
 Jep jep = new Jep(new StandardConfigurableParser());
 OperatorTableI opTab = jep.getOperatorTable();
 Operator eqOp = opTab.getEQ();
 Operator inOp = new Operator(
   "IN",
   new ElementOf((Comparative) eqOp.getPFMC(),true),
   Operator.BINARY+Operator.RIGHT);
 Operator notInOp = new Operator(
   "NOTIN",
   new ElementOf((Comparative) eqOp.getPFMC(),false),
   Operator.BINARY+Operator.RIGHT);
 opTab.addOperator(InOperators.IN,inOp,eqOp);
 opTab.addOperator(InOperators.NOTIN,notInOp,eqOp);
 jep.reinitializeComponents();
 

Since:

3.5.0

Author:

Richard Morris

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.singularsys.jep.functions.ArrayFunctionBase

ArrayFunctionBase.ZeroLengthErrorBehaviour

Field Summary

Fields

Modifier and Type	Field	Description
protected final Comparative	comp

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

curNumberOfParameters, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
ElementOf(Comparative comp, boolean elementOf)	Construct the function.

Method Summary

Modifier and Type	Method	Description
protected Object	calc(Object first, List<Object> l)	Calculates if the element is in the list or not.
protected Object	calc(List<Object> l)	Should not be called.
void	run(Stack<Object> stack)	Calls the calc method after concatenating the second and subsequent elements into list.

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

addToArray, checkNumberOfParameters, getZeroLengthErrorBehaviour, setZeroLengthErrorBehaviour, throwAtLeastOneExcep

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

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, getName, getNumberOfParameters, setCurNumberOfParameters, setName, toString, toString

Methods inherited from class java.lang.Object

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

Field Details

comp

protected final Comparative comp

Constructor Details

ElementOf

public ElementOf(Comparative comp,
 boolean elementOf)

Construct the function.

Parameters:

comp - comparative object used to compare two elements

elementOf - whether the function calculate "element-of" or "not element-of". If false the result of function is negated.

Method Details

calc

protected Object calc(Object first,
 List<Object> l)
               throws EvaluationException

Calculates if the element is in the list or not.

Parameters:

first - element to test

l - list with all the other arguments in the list

Returns:

Boolean.TRUE or Boolean.FALSE depending on if the element is in the list.

Throws:

EvaluationException

run

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

Calls the calc method after concatenating the second and subsequent elements into list.

Specified by:

run in interface PostfixMathCommandI

Overrides:

run in class ArrayFunctionBase

Parameters:

stack - arguments for function

Throws:

EvaluationException - if function cannot be evaluated

calc

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

Should not be called.

Specified by:

calc in class ArrayFunctionBase

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 - always