Package com.singularsys.jep.misc.nullwrapper

Class NullWrappedFunctionFactory

  • All Implemented Interfaces:
    JepComponent, java.io.Serializable
    public class NullWrappedFunctionFactory
extends java.lang.Object
implements JepComponent
    A factory to create the appropriate type of wrapped function.
    Author:
    Richard Morris
    See Also:
    Serialized Form

    • Constructor Detail

      • NullWrappedFunctionFactory

        public NullWrappedFunctionFactory()

    • Method Detail

      • getWrappedFunction

        public PostfixMathCommandI getWrappedFunction​(PostfixMathCommandI fun)
        Gets a wrapped function, returns a function which will handle null values correctly. This method:
        • Calls getSpecialFunction(PostfixMathCommandI) and returns any non null results.
        • If fun implements CallbackEvaluationI then it cannot be wrapped and null is returned.
        • If fun implements NullWrappedFunctionI then it is alread wrapped and fun is returned.
        • If fun implements UnaryFunction then it is wrapped by NullWrapperUnary which is returned.
        • If fun implements BinaryFunction then it is wrapped by NullWrapperBinary which is returned.
        • If fun implements NaryFunction then it is wrapped by NullWrapperNary which is returned.
        • If fun implements NaryBinaryFunction then it is wrapped by NullWrapperNaryBinary which is returned.
        • If fun has zero arguments then it does not need to wrap functions and fun.
        • If fun implements PostfixMathCommand then it is wrapped by NullWrapperPfmc which is returned.
        • Otherwise fun is returned.
        Parameters:
        fun - the function to be wrapped
        Returns:
        the wrapped function or null see above for details

      • getSpecialFunction

        protected PostfixMathCommandI getSpecialFunction​(PostfixMathCommandI fun)
        Handles special functions. Subclasses can override this method to add treatment of other special functions. This methods performs the following actions:
        • If and TernaryConditional are replaced by NullWrappedIf.
        • LazyLogical functions are replaced by NullLazyLogical.
        • Increment functions which extend AbstractInc are wrapped by NullAbstractInc
        • Assign, List, Ele, IsNull, all handle null correctly so the original function is returned.
        • For Case, Switch, SwitchDefault instances of these which handle nulls correctly are returned.
        Parameters:
        fun - original function
        Returns:
        the new function or null if no special function found.

      • init

        public void init​(Jep jep)
        Description copied from interface: JepComponent
        Initialize the component. This methods is called whenever a component is added to Jep. Hence it allows components to keep track of the other components they may rely on.
        Specified by:
        init in interface JepComponent
        Parameters:
        jep - the current Jep instance