Package org.apache.commons.functor.adapter

Class PredicateFunction

  • All Implemented Interfaces:
    java.io.Serializable, Function<java.lang.Boolean>, Functor, NullaryFunctor
    public final class PredicateFunction
extends java.lang.Object
implements Function<java.lang.Boolean>, java.io.Serializable
    Adapts a Predicate to the Function interface.

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

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

    • Constructor Summary

      Constructors 
      Constructor Description
      PredicateFunction​(Predicate predicate)
      Create a new PredicateFunction.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      static PredicateFunction adapt​(Predicate predicate)
      Adapt a Predicate to the Function interface.
      boolean equals​(java.lang.Object that)
      Indicates whether some other object is "equal to" this functor.
      boolean equals​(PredicateFunction that)
      Learn whether another PredicateFunction is equal to this.
      java.lang.Boolean 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

    • Constructor Detail

      • PredicateFunction

        public PredicateFunction​(Predicate predicate)
        Create a new PredicateFunction.
        Parameters:
        predicate - to adapt

    • Method Detail

      • evaluate

        public java.lang.Boolean evaluate()
        Evaluate this function. Returns Boolean.TRUE (Boolean.FALSE) when the test method of my underlying predicate returns true (false).
        Specified by:
        evaluate in interface Function<java.lang.Boolean>
        Returns:
        a non-null Boolean instance

      • 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​(PredicateFunction that)
        Learn whether another PredicateFunction is equal to this.
        Parameters:
        that - PredicateFunction 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

      • adapt

        public static PredicateFunction adapt​(Predicate predicate)
        Adapt a Predicate to the Function interface.
        Parameters:
        predicate - to adapt
        Returns:
        PredicateFunction