Class Case

  • 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 example case("c","a",5,"b",6,"c",7,8) will return 7.
    Author:
    Richard Morris
    See Also:
    Switch, Serialized Form
    • Constructor Detail

      • Case

        public Case()
        Standard constructor with no default value and errors if null if 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​(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
      • 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 match
        nullBehaviour - action to take if first argument is null
        Since:
        Jep 3.5
    • Method Detail

      • isHasDefault

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

        public java.lang.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
      • 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