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, 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:

  • Constructor Details

    • 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 Details

    • 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 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: