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, HsmKeyStoreLoader, 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:

  • Method Summary

    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 Details

    • apply

      VOUT apply(VIN value) throws E
      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.

    • compose

      default <V> Function<V,VOUT,E> compose(Function<? super V,? extends VIN,E> before) throws E
      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

      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:

    • 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.