Package org.forgerock.util

Interface Function<VIN,​VOUT,​E extends Exception>

  • Type Parameters:
    VIN - The type of the function parameter, or Void if the function does not expect a parameter.
    VOUT - The type of the function result, or Void if the function does not return anything (i.e. it only has side-effects).
    E - The type of the exception thrown by the function, or NeverThrowsException if no exception is thrown by the function.
    All Known Implementing Classes:
    CloseSilentlyFunction, JsonValueTraverseFunction
    Functional Interface:
    This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
    @FunctionalInterface
public interface Function<VIN,​VOUT,​E extends Exception>
    A synchronous function which returns a result immediately.

    Exception handling: implementations which do not throw any exceptions should declare that they throw an exception of type NeverThrowsException.

    Example usage: 

     public class IsPossiblePrime implements Function<String, Boolean, IllegalArgumentException> {
     public Boolean apply(String value) throws IllegalArgumentException {
         // Parse the parameter now and potentially immediately throw an
         // exception.
         final BigInteger possiblePrime = new BigInteger(value);

         // Determine if the parameter is a prime number.
         return possiblePrime.isProbablePrime(1000);
     }
 }
    See Also:
    AsyncFunction, NeverThrowsException

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Default Methods 
      Modifier and Type Method Description
      default <V> Function<VIN,​V,​E> andThen​(Function<? super VOUT,​? extends V,​E> after)
      Returns a composed function that first applies this function to its input, and then applies the after function to the result.
      VOUT apply​(VIN value)
      Applies this function to the input parameter value and returns the result.
      default <V> Function<V,​VOUT,​E> compose​(Function<? super V,​? extends VIN,​E> before)
      Returns a composed function that first applies the before function to its input, and then applies this function to the result.
      static <V,​E extends Exception>
      Function<V,​V,​E>      		 identity()
      Returns an identity function that returns the input as output.

    • Method Detail

      • apply

        VOUT apply​(VIN value)
    throws E extends Exception
        Applies this function to the input parameter value and returns the result.
        Parameters:
        value - The input parameter.
        Returns:
        The result of applying this function to value.
        Throws:
        E - If this function cannot be applied to value.
        E extends Exception

      • compose

        default <V> Function<V,​VOUT,​E> compose​(Function<? super V,​? extends VIN,​E> before)
                                            throws E extends Exception
        Returns a composed function that first applies the before function to its input, and then applies this function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function.
        Type Parameters:
        V - the type of input to the before function, and to the composed function
        Parameters:
        before - the function to apply before this function is applied
        Returns:
        a composed function that first applies the before function and then applies this function
        Throws:
        NullPointerException - if before is null
        E extends Exception
        See Also:
        andThen(Function)

      • andThen

        default <V> Function<VIN,​V,​E> andThen​(Function<? super VOUT,​? extends V,​E> after)
        Returns a composed function that first applies this function to its input, and then applies the after function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function.
        Type Parameters:
        V - the type of output of the after function, and of the composed function
        Parameters:
        after - the function to apply after this function is applied
        Returns:
        a composed function that first applies this function and then applies the after function
        Throws:
        NullPointerException - if after is null
        See Also:
        compose(Function)

      • identity

        static <V,​E extends Exception> Function<V,​V,​E> identity()
        Returns an identity function that returns the input as output.
        Type Parameters:
        V - the input/output type
        E - The type of the exception thrown by the function, or NeverThrowsException if no exception is thrown by the function.
        Returns:
        an identity function that will return a result promise of the input.