/*

  Copyright 2004-2008 Paul R. Holser, Jr.  All rights reserved.

  Licensed under the Academic Free License version 3.0

  */

 package jaggregate.internal;

 import jaggregate.UnaryCondition;

 import static jaggregate.internal.ArgumentChecks.*;

 /**

  * @author <a href="mailto:pholser@alumni.rice.edu">Paul Holser</a>

  * @version $Id: UnaryConditions.java,v 1.2 2008/10/03 19:01:23 pholser Exp $

  */

 public class UnaryConditions {

     /**

      * Discourages instantiation.

      *

      * @throws UnsupportedOperationException always

      */

     protected UnaryConditions() {

         throw new UnsupportedOperationException();

     }

     /**

      * Answers a predicate that represents the logical <dfn>inverse</dfn> of the given

      * predicate; wherever the given predicate's {@link UnaryCondition#matches(Object)

      * matches} method would answer {@code true}, the inverse answers {@code false};

      * and vice versa.

      *

      * @param <T> constraint on the types accepted by the condition

      * @param condition the condition to invert

      * @return the inverse of {@code condition}

      * @throws NullPointerException if {@code condition} is {@code null}

      */

     public static <T> UnaryCondition<T> not( final UnaryCondition<T> condition ) {

         ensureNotNull( condition, DISCRIMINATOR );

         return new UnaryCondition<T>() {

             public boolean matches( T target ) {

                 return !condition.matches( target );

             }

         };

     }

 }