| /* |
| * 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.lang3.Validate; |
| |
| /** |
| * Adapts a {@link Comparator Comparator} to the |
| * {@link BinaryFunction} interface. |
| * |
| * @param <T> the binary function input types |
| * @version $Revision$ $Date$ |
| * @author Rodney Waldhoff |
| */ |
| public final class ComparatorFunction<T> implements BinaryFunction<T, T, Integer>, Serializable { |
| |
| /** |
| * Basic ComparatorFunction instance. |
| */ |
| public static final ComparatorFunction<Comparable<?>> INSTANCE = ComparatorFunction.<Comparable<?>>instance(); |
| |
| /** |
| * serialVersionUID declaration. |
| */ |
| private static final long serialVersionUID = 1642024869929206095L; |
| |
| /** |
| * The comparator to wrap. |
| */ |
| private final Comparator<? super T> comparator; |
| |
| /** |
| * Create a new ComparatorFunction. |
| * @param comparator to wrap |
| */ |
| public ComparatorFunction(Comparator<? super T> comparator) { |
| this.comparator = Validate.notNull(comparator, "Comparator argument must not be null"); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public Integer evaluate(T left, T right) { |
| return Integer.valueOf(comparator.compare(left, right)); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean equals(Object that) { |
| return that == this || (that instanceof ComparatorFunction<?> && equals((ComparatorFunction<?>) that)); |
| } |
| |
| /** |
| * Learn whether a specified ComparatorFunction is equal to this. |
| * @param that the ComparatorFunction to test |
| * @return boolean |
| */ |
| public boolean equals(ComparatorFunction<?> that) { |
| return null != that && comparator.equals(that.comparator); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int hashCode() { |
| return "ComparatorFunction".hashCode() ^ comparator.hashCode(); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public String toString() { |
| return "ComparatorFunction<" + comparator + ">"; |
| } |
| |
| /** |
| * Get a basic ComparatorFunction instance. |
| * |
| * @param <T> the binary function input types |
| * @return ComparatorFunction |
| */ |
| @SuppressWarnings("unchecked") |
| public static <T> ComparatorFunction<T> instance() { |
| return new ComparatorFunction<T>(ComparableComparator.INSTANCE); |
| } |
| } |