Package com.singularsys.jep.misc.functions

# Class SwitchDefault

java.lang.Object
com.singularsys.jep.functions.PostfixMathCommand
com.singularsys.jep.misc.functions.SwitchDefault

All Implemented Interfaces:
  `CallbackEvaluationI`, `PostfixMathCommandI`, `Serializable`

public class SwitchDefault extends PostfixMathCommand implements CallbackEvaluationI
A switch statement, with a default value. The argument is selected based on the integer value of the first argument, the last argument is returned if the first argument is greater than the number of arguments -2. For example `switchDefault(2,5,6,7,8)` will return 5, and `switchDefault(9,5,6,7,8)` will return 8. The first argument must be an exact integer.

This is the lazy evaluation version, it will only evaluate arguments when needed. Use `SwitchDefaultNonLazy` for a non-lazy version which evaluates all arguments before evaluation.

Author:
  Richard Morris
See Also:
  - `Case`
  - `Switch`
  - Serialized Form

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static enum`
  `SwitchDefault.NullBehaviour`
  Action to take if first argument is null.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected SwitchDefault.NullBehaviour`
  `nullBehaviour`

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

  `curNumberOfParameters, description, name, NaN, numberOfParameters`

- ## Constructor Summary

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

- ## Method Summary

  Modifier and Type
  Method
  Description
  `boolean`
  `checkNumberOfParameters(int n)`
  Checks the number of parameters of the function.
  `Object`
  `evaluate(Node node, Evaluator pv)`
  Performs some special evaluation on the node.
  `SwitchDefault.NullBehaviour`
  `getNullBehaviour()`
  Behaviour when passed zero arguments.

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

  `asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, asType, getDescription, getDescription, getDescriptionWithType, getName, getNumberOfParameters, run, setCurNumberOfParameters, setDescription, setName, toString, toString`

  ### Methods inherited from class java.lang.Object

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

- ## Field Details

  - ### nullBehaviour

    protected SwitchDefault.NullBehaviour nullBehaviour

- ## Constructor Details

  - ### SwitchDefault

    public SwitchDefault()
    Default switch statement. Exceptions are thrown if first argument is null.

  - ### SwitchDefault

    public SwitchDefault(SwitchDefault.NullBehaviour nullBehaviour)
    Switch function with defined null behaviour.
    Parameters:
      `nullBehaviour` - action to take if first argument is null.
    Since:
      Jep 3.5

- ## Method Details

  - ### checkNumberOfParameters

    public boolean checkNumberOfParameters(int n)
    Description copied from class: `PostfixMathCommand`
    Checks the number of parameters of the function. Functions which set numberOfParameter=-1 should overload this method
    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.

  - ### getNullBehaviour

    public SwitchDefault.NullBehaviour getNullBehaviour()
    Behaviour when passed zero arguments.
    Returns:
      code indicating behaviour type
    Since:
      Jep 3.5

  - ### 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:
      - `Evaluator`