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, java.io.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:
    `Case`, Serialized Form

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `Switch.NullBehaviour` Action to take if first argument is null.

  - ### Field Summary

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

      `curNumberOfParameters, name, NaN, numberOfParameters`

  - ### Constructor Summary

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

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `checkNumberOfParameters(int n)` Must have at least 2 parameters.
    `java.lang.Object` | `evaluate(Node node, Evaluator pv)` Performs some special evaluation on the node.
    `Switch.NullBehaviour` | `getNullBehaviour()` Behaviour when passed zero arguments.

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

      `asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, getName, getNumberOfParameters, run, setCurNumberOfParameters, setName, toString, toString`

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

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

- - ### Constructor Detail

    - #### 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 Detail

    - #### 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 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`

Copyright © 2018 Singular Systems http://www.singularsys.com/jep