Package org.apache.commons.functor.adapter

Class BoundFunction<T>

  • Type Parameters:
    T - the returned value type.
    All Implemented Interfaces:
    java.io.Serializable, Function<T>, Functor, NullaryFunctor
    public final class BoundFunction<T>
extends java.lang.Object
implements Function<T>, java.io.Serializable
    Adapts a UnaryFunction to the Function interface using a constant unary argument.

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

    Version:
    $Revision$ $Date$
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private java.lang.Object arg
      The argument to pass to function.
      private UnaryFunction<java.lang.Object,​? extends T> function
      The UnaryFunction I'm wrapping.
      private static long serialVersionUID
      serialVersionUID declaration.

    • Constructor Summary

      Constructors 
      Constructor Description
      BoundFunction​(UnaryFunction<? super A,​? extends T> function, A arg)
      Create a new BoundFunction instance.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      static <A,​T>
      BoundFunction<T>      		 bind​(UnaryFunction<? super A,​? extends T> function, A arg)
      Adapt the given, possibly-null, UnaryFunction to the Function interface by binding the specified Object as a constant argument.
      boolean equals​(java.lang.Object that)
      Indicates whether some other object is "equal to" this functor.
      boolean equals​(BoundFunction<?> that)
      Learn whether another BoundFunction is equal to this.
      T evaluate()
      Evaluate this function.
      int hashCode()
      Returns a hash code for this functor adhering to the general Object.hashCode contract.
      java.lang.String toString()
      Returns a human readable description of this functor.

      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    • Field Detail

      • serialVersionUID

        private static final long serialVersionUID
        serialVersionUID declaration.
        See Also:
        Constant Field Values

      • arg

        private final java.lang.Object arg
        The argument to pass to function.

    • Constructor Detail

      • BoundFunction

        public BoundFunction​(UnaryFunction<? super A,​? extends T> function,
                     A arg)
        Create a new BoundFunction instance.
        Type Parameters:
        A - the argument value type
        Parameters:
        function - the function to adapt
        arg - the constant argument to use

    • Method Detail

      • evaluate

        public T evaluate()
        Evaluate this function.
        Specified by:
        evaluate in interface Function<T>
        Returns:
        the T result of this evaluation

      • equals

        public boolean equals​(java.lang.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 java.lang.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:
        Functor.hashCode()

      • equals

        public boolean equals​(BoundFunction<?> that)
        Learn whether another BoundFunction is equal to this.
        Parameters:
        that - BoundFunction 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 java.lang.Object
        Returns:
        a hash code for this functor
        See Also:
        Functor.equals(java.lang.Object)

      • toString

        public java.lang.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 java.lang.Object
        Returns:
        a human readable description of this functor

      • bind

        public static <A,​T> BoundFunction<T> bind​(UnaryFunction<? super A,​? extends T> function,
                                                A arg)
        Adapt the given, possibly-null, UnaryFunction to the Function interface by binding the specified Object as a constant argument. When the given UnaryFunction is null, returns null.
        Type Parameters:
        A - input type
        T - result type
        Parameters:
        function - the possibly-null UnaryFunction to adapt
        arg - the object to bind as a constant argument
        Returns:
        a BoundFunction wrapping the given UnaryFunction, or null if the given UnaryFunction is null