Package com.singularsys.jep.misc.functions

Class Case

java.lang.Object
com.singularsys.jep.functions.PostfixMathCommand
com.singularsys.jep.misc.functions.Case
All Implemented Interfaces:
CallbackEvaluationI, PostfixMathCommandI, 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 example case("c","a",5,"b",6,"c",7,8) will return 7.
Author:
Richard Morris
See Also:

  • Constructor Details

    • Case

      public Case()
      Standard constructor with no default value and errors if nulls are found.

    • 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

    • Case

      public Case(Object defaultVal)
      A case statement with a predefined default value and errors if nulls are found.
      Parameters:
      defaultVal - The default value to return when no cases match
      Since:
      Jep 3.5

    • Case

      public Case(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 match
      nullBehaviour - action to take if first argument is null
      Since:
      Jep 3.5

  • Method Details

    • isHasDefault

      public boolean isHasDefault()
      Whether a default value is set
      Returns:
      true if a default value is set
      Since:
      Jep 3.5

    • getDefaultVal

      public Object getDefaultVal()
      The default value, only meaningful if isHasDefault() is true.
      Returns:
      the default value used.
      Since:
      Jep 3.5

    • getNullBehaviour

      public Case.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 3 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 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: