Package com.singularsys.jep.functions
Class If
- java.lang.Object
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- com.singularsys.jep.functions.PostfixMathCommand
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- com.singularsys.jep.functions.If
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- All Implemented Interfaces:
CallbackEvaluationI
,PostfixMathCommandI
,java.io.Serializable
- Direct Known Subclasses:
NullWrappedIf
public class If extends PostfixMathCommand implements CallbackEvaluationI
The if(condExpr, posExpr, negExpr) function. The value of trueExpr will be returned if condExpr is >0 or Boolean.TRUE and value of negExpr will be returned if condExpr is <= 0 or Boolean.TRUE. If condExpr is NaN then NaN is returned.This function performs lazy evaluation so that only posExpr or negExpr will be evaluated. For Complex numbers only the real part is used.
An alternate form if(condExpr, posExpr, negExpr, zeroExpr) is also available. Note most computations are carried out over floating point doubles so testing for zero can be dangerous.
Note most computations are carried out over floating point doubles so testing for zero can be dangerous.
- Since:
- Feb 05 Handles Number arguments, so works with Integers rather than just Doubles
- Version:
- 2.3.0 beta 1 now supports a Boolean first argument.
- Author:
- Rich Morris Created on 18-Nov-2003
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected java.lang.Object
falseValue
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Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand
curNumberOfParameters, name, NaN, numberOfParameters
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
checkNumberOfParameters(int n)
Checks the number of parameters of the call.java.lang.Object
evaluate(Node node, Evaluator pv)
Performs some special evaluation on the node.java.lang.Object
getFalseValue()
The value returned for false values in the two argument version.-
Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand
asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, getName, getNumberOfParameters, run, setCurNumberOfParameters, setName, toString, toString
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Method Detail
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checkNumberOfParameters
public boolean checkNumberOfParameters(int n)
Checks the number of parameters of the call.- Specified by:
checkNumberOfParameters
in interfacePostfixMathCommandI
- Overrides:
checkNumberOfParameters
in classPostfixMathCommand
- Parameters:
n
- number of parameters function will be called with.- Returns:
- false if an illegal number of parameters is supplied, true otherwise.
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evaluate
public java.lang.Object evaluate(Node node, Evaluator pv) throws EvaluationException
Description copied from interface:CallbackEvaluationI
Performs some special evaluation on the node. This method has the responsibility for evaluating the children of the node and it should generally callpv.eval(node.jjtGetChild(i))
for each child. The SymbolTable is not passed as an argument. This is because it is better practice to get and set variable values by using node.getVar().setValue() rather that through the SymbolTable with requires a hashtable lookup.- Specified by:
evaluate
in interfaceCallbackEvaluationI
- Parameters:
node
- The current nodepv
- The visitor, can be used evaluate the children- Returns:
- the value after evaluation. This value will be passed to other functions higher up the node tree. The value can be any type including Double or Vector<Object>
- Throws:
EvaluationException
- if the calculation cannot be performed- See Also:
Evaluator
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getFalseValue
public java.lang.Object getFalseValue()
The value returned for false values in the two argument version.- Returns:
- value returned
- Since:
- 3.4.0
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