Package com.singularsys.jep.misc.functions

Class Switch

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.misc.functions.Switch

All Implemented Interfaces:

CallbackEvaluationI, PostfixMathCommandI, java.io.Serializable

public class Switch
extends PostfixMathCommand
implements CallbackEvaluationI

A switch statement. The argument is selected based on the integer value of the first argument for example switch(2,5,6,7,8) will return 6. The first argument must be an exact integer

Author:

Richard Morris

See Also:

Case, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Switch.NullBehaviour	Action to take if first argument is null.

Field Summary

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

curNumberOfParameters, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
Switch()	Default switch statement.
Switch(Switch.NullBehaviour nullBehaviour)	Switch function with defined null behaviour.

Method Summary

Modifier and Type	Method	Description
boolean	checkNumberOfParameters(int n)	Must have at least 2 parameters.
java.lang.Object	evaluate(Node node, Evaluator pv)	Performs some special evaluation on the node.
Switch.NullBehaviour	getNullBehaviour()	Behaviour when passed zero arguments.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

Switch

public Switch()

Default switch statement. Exceptions are thrown if first argument is null.

Switch

public Switch(Switch.NullBehaviour nullBehaviour)

Switch function with defined null behaviour.

Parameters:

nullBehaviour - action to take if first argument is null.

Since:

Jep 3.5

Method Detail

getNullBehaviour

public Switch.NullBehaviour getNullBehaviour()

Behaviour when passed zero arguments.

Returns:

code indicating behaviour type

Since:

Jep 3.5

checkNumberOfParameters

public boolean checkNumberOfParameters(int n)

Must have at least 2 parameters.

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.

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 call

 pv.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 interface CallbackEvaluationI

Parameters:

node - The current node

pv - 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