Class CompositeUnaryFunction<A,T>

java.lang.Object
org.apache.commons.functor.core.composite.CompositeUnaryFunction<A,T>
Type Parameters:
A - the argument type.
T - the returned value type.
All Implemented Interfaces:
Serializable, Functor, UnaryFunction<A,T>, UnaryFunctor<A>
public class CompositeUnaryFunction<A,T> extends Object implements UnaryFunction<A,T>, Serializable
A UnaryFunction representing the composition of UnaryFunctions, "chaining" the output of one to the input of another. For example, 
new CompositeUnaryFunction(f).of(g)
evaluates to f.evaluate(g.evaluate(obj)), and 
new CompositeUnaryFunction(f).of(g).of(h)
evaluates to f.evaluate(g.evaluate(h.evaluate(obj))).

When the collection is empty, this function is an identity function.

Note that although this class implements Serializable, a given instance will only be truly Serializable if all the underlying functors are. Attempts to serialize an instance whose delegates are not all Serializable will result in an exception.

Version:
$Revision$ $Date$
See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      serialVersionUID declaration.
      See Also:

    • HASH_SHIFT

      private static final int HASH_SHIFT
      Base hash integer used to shift hash.
      See Also:

    • function

      private final UnaryFunction<? super A, ? extends T> function
      The adapted function.

  • Constructor Details

    • CompositeUnaryFunction

      public CompositeUnaryFunction(UnaryFunction<? super A, ? extends T> function)
      Create a new CompositeUnaryFunction.
      Parameters:
      function - UnaryFunction to call

    • CompositeUnaryFunction

      private <X> CompositeUnaryFunction(UnaryFunction<? super X, ? extends T> following, UnaryFunction<? super A, ? extends X> preceding)
      Creates a new CompositeUnaryFunction instance given the input functions.
      Type Parameters:
      X - the argument type.
      Parameters:
      following - The first evaluator function.
      preceding - The last evaluator function.

  • Method Details

    • evaluate

      public final T evaluate(A obj)
      Evaluate this function.
      Specified by:
      evaluate in interface UnaryFunction<A,T>
      Parameters:
      obj - the A object to evaluate
      Returns:
      the T result of this evaluation

    • of

      public final <P> CompositeUnaryFunction<P,T> of(UnaryFunction<? super P, ? extends A> preceding)
      Fluently obtain a CompositeUnaryFunction that is "this function" applied to the specified preceding function.
      Type Parameters:
      P - argument type of the resulting function.
      Parameters:
      preceding - UnaryFunction
      Returns:
      CompositeUnaryFunctioninvalid input: '<'P, T>

    • equals

      public final boolean equals(Object that)
      Indicates whether some other object is "equal to" this functor. This method must adhere to general Object.equals contract. Additionally, this method can return true only if the specified Object implements the same functor interface and is known to produce the same results and/or side-effects for the same arguments (if any).

      While implementators are strongly encouraged to override the default Object implementation of this method, note that the default Object implementation does in fact adhere to the functor equals contract.

      Specified by:
      equals in interface Functor
      Overrides:
      equals in class Object
      Parameters:
      that - the object to compare this functor to
      Returns:
      true iff the given object implements this functor interface, and is known to produce the same results and/or side-effects for the same arguments (if any).
      See Also:

    • equals

      public final boolean equals(CompositeUnaryFunction<?,?> that)
      Learn whether another CompositeUnaryFunction is equal to this.
      Parameters:
      that - CompositeUnaryFunction to test
      Returns:
      boolean

    • hashCode

      public int hashCode()
      Returns a hash code for this functor adhering to the general Object.hashCode contract. Implementators are strongly encouraged but not strictly required to override the default Object implementation of this method.
      Specified by:
      hashCode in interface Functor
      Overrides:
      hashCode in class Object
      Returns:
      a hash code for this functor
      See Also:

    • toString

      public String toString()
      Returns a human readable description of this functor. Implementators are strongly encouraged but not strictly required to override the default Object implementation of this method.
      Specified by:
      toString in interface Functor
      Overrides:
      toString in class Object
      Returns:
      a human readable description of this functor