Class Identity<T>

java.lang.Object
org.apache.commons.functor.core.Identity<T>
Type Parameters:
T - the returned value type.
All Implemented Interfaces:
Serializable, Functor, UnaryFunction<T,T>, UnaryFunctor<T>, UnaryPredicate<T>
public final class Identity<T> extends Object implements UnaryFunction<T,T>, UnaryPredicate<T>, Serializable
Evaluates to its input argument. Tests to the boolean value of the Boolean-valued parameter. The test(Object) method throws an exception if the parameter isn't a non-null Boolean.
Version:
$Revision$ $Date$
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final Identity<Object>
    INSTANCE
    A generic Identity<Object> instance.
    private static final long
    serialVersionUID
    serialVersionUID declaration.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Identity()
    Create a new Identity.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    equals(Object that)
    Indicates whether some other object is "equal to" this functor.
    T
    evaluate(T obj)
    Evaluate this function.
    int
    hashCode()
    Returns a hash code for this functor adhering to the general Object.hashCode contract.
    static <T> Identity<T>
    instance()
    Get an Identity instance.
    boolean
    test(Boolean bool)
    Test a Boolean object by returning its booleanValue.
    boolean
    test(Object obj)
    Evaluate this predicate.
    String
    toString()
    Returns a human readable description of this functor.

    Methods inherited from class Object

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

  • Field Details

    • INSTANCE

      public static final Identity<Object> INSTANCE
      A generic Identity<Object> instance.

    • serialVersionUID

      private static final long serialVersionUID
      serialVersionUID declaration.
      See Also:

  • Constructor Details

    • Identity

      public Identity()
      Create a new Identity.

  • Method Details

    • evaluate

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

    • test

      public boolean test(Object obj)
      Evaluate this predicate.
      Specified by:
      test in interface UnaryPredicate<T>
      Parameters:
      obj - the A object to test
      Returns:
      the result of this test

    • test

      public boolean test(Boolean bool)
      Test a Boolean object by returning its booleanValue.
      Parameters:
      bool - Boolean
      Returns:
      boolean

    • equals

      public 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:

    • 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

    • instance

      public static <T> Identity<T> instance()
      Get an Identity instance.
      Type Parameters:
      T - the identity returned value type.
      Returns:
      Identity