Class Case
- java.lang.Object
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- com.singularsys.jep.functions.PostfixMathCommand
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- com.singularsys.jep.misc.functions.Case
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- All Implemented Interfaces:
CallbackEvaluationI
,PostfixMathCommandI
,java.io.Serializable
public class Case extends PostfixMathCommand implements CallbackEvaluationI
A case statement. The argument first argument is evaluated and then checked against the 2nd, 4th, 6th argument if the two are equal then the 3rd, 5th, 7th argument is returned. If no arguments match then the last argument is returned (if the number of args is even) for examplecase("c","a",5,"b",6,"c",7,8)
will return 7.- Author:
- Richard Morris
- See Also:
Switch
, Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Case.NullBehaviour
Action to take if first argument is null.
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Field Summary
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Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand
curNumberOfParameters, name, NaN, numberOfParameters
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Constructor Summary
Constructors Constructor Description Case()
Standard constructor with no default value and errors if null if found.Case(Case.NullBehaviour nullBehaviour)
Constructor with defined behaviour for null.Case(java.lang.Object defaultVal)
A case statement with a predefined default value and errors if null if found.Case(java.lang.Object defaultVal, Case.NullBehaviour nullBehaviour)
Case statement with given default value and defined null behaviour.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
checkNumberOfParameters(int n)
Must have at least 3 parameters.java.lang.Object
evaluate(Node node, Evaluator pv)
Performs some special evaluation on the node.java.lang.Object
getDefaultVal()
The default value, only meaningful if isHasDefault() is true.Case.NullBehaviour
getNullBehaviour()
Behaviour when passed zero arguments.boolean
isHasDefault()
Whether a default value is set-
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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Constructor Detail
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Case
public Case()
Standard constructor with no default value and errors if null if found.
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Case
public Case(Case.NullBehaviour nullBehaviour)
Constructor with defined behaviour for null.- Parameters:
nullBehaviour
- action to take if first argument is null- Since:
- Jep 3.5
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Case
public Case(java.lang.Object defaultVal)
A case statement with a predefined default value and errors if null if found.- Parameters:
defaultVal
- The default value to return when no cases match- Since:
- Jep 3.5
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Case
public Case(java.lang.Object defaultVal, Case.NullBehaviour nullBehaviour)
Case statement with given default value and defined null behaviour.- Parameters:
defaultVal
- The default value to return when no cases matchnullBehaviour
- action to take if first argument is null- Since:
- Jep 3.5
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Method Detail
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isHasDefault
public boolean isHasDefault()
Whether a default value is set- Returns:
- true if a default value is set
- Since:
- Jep 3.5
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getDefaultVal
public java.lang.Object getDefaultVal()
The default value, only meaningful if isHasDefault() is true.- Returns:
- the default value used.
- Since:
- Jep 3.5
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getNullBehaviour
public Case.NullBehaviour getNullBehaviour()
Behaviour when passed zero arguments.- Returns:
- code indicating behaviour type
- Since:
- Jep 3.5
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checkNumberOfParameters
public boolean checkNumberOfParameters(int n)
Must have at least 3 parameters.- 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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