/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  *

  *      http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.commons.functor.core.comparator;

 import java.io.Serializable;

 import java.util.Comparator;

 import org.apache.commons.functor.BinaryFunction;

 import org.apache.commons.functor.UnaryFunction;

 import org.apache.commons.functor.adapter.RightBoundFunction;

 /**

  * Adapts a {@link Comparator Comparator} to the

  * {@link BinaryFunction} interface.

  *

  * @version $Revision: 1166355 $ $Date: 2011-09-07 21:54:29 +0200 (Wed, 07 Sep 2011) $

  * @author Rodney Waldhoff

  */

 public final class Min<T> implements BinaryFunction<T, T, T>, Serializable {

     /**

      * Basic Min instance.

      */

     public static final Min<Comparable<?>> INSTANCE = Min.<Comparable<?>>instance();

     /**

      * serialVersionUID declaration.

      */

     private static final long serialVersionUID = 9190170976707323848L;

     private final Comparator<T> comparator;

     /**

      * Create a new Min.

      */

     @SuppressWarnings("unchecked")

     public Min() {

         this(ComparableComparator.instance());

     }

     /**

      * Create a new Min.

      * @param comparator to use

      */

     public Min(Comparator<T> comparator) {

         if (comparator == null) {

             throw new IllegalArgumentException("Comparator argument must not be null");

         }

         this.comparator = comparator;

     }

     /**

      * {@inheritDoc}

      */

     public T evaluate(T left, T right) {

         return (comparator.compare(left, right) <= 0) ? left : right;

     }

     /**

      * {@inheritDoc}

      */

     public boolean equals(Object that) {

         return that == this || (that instanceof Min<?> && equals((Min<?>) that));

     }

     /**

      * Learn whether another Min is equal to this.

      * @param that Min to test

      * @return boolean

      */

     public boolean equals(Min<?> that) {

         return null != that && comparator.equals(that.comparator);

     }

     /**

      * {@inheritDoc}

      */

     public int hashCode() {

         return "Min".hashCode() ^ comparator.hashCode();

     }

     /**

      * {@inheritDoc}

      */

     public String toString() {

         return "Min<" + comparator + ">";

     }

     /**

      * Get a basic Min instance.

      * @return Min

      */

     public static <T extends Comparable<?>> Min<T> instance() {

         return new Min<T>();

     }

     /**

      * Get a Min UnaryFunction.

      * @param right the right side argument of the Min function

      * @return UnaryFunction<T, T>

      */

     public static <T extends Comparable<?>> UnaryFunction<T, T> instance(T right) {

         return RightBoundFunction.bind(new Min<T>(), right);

     }

 }