    001/*
    002    Licensed to the Apache Software Foundation (ASF) under one
    003    or more contributor license agreements.  See the NOTICE file
    004    distributed with this work for additional information
    005    regarding copyright ownership.  The ASF licenses this file
    006    to you under the Apache License, Version 2.0 (the
    007    "License"); you may not use this file except in compliance
    008    with the License.  You may obtain a copy of the License at
    009
    010       http://www.apache.org/licenses/LICENSE-2.0
    011
    012    Unless required by applicable law or agreed to in writing,
    013    software distributed under the License is distributed on an
    014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015    KIND, either express or implied.  See the License for the
    016    specific language governing permissions and limitations
    017    under the License.
    018 */
    019
    020package org.apache.wiki.util.comparators;
    021
    022import org.apache.commons.lang3.Strings;
    023
    024import java.util.Comparator;
    025
    026/**
    027 * A comparator that sorts Strings using Java's "natural" order.
    028 *
    029 */
    030public class JavaNaturalComparator implements Comparator<String>
    031{
    032    // A special singleton instance for quick access
    033    public static final Comparator<String> DEFAULT_JAVA_COMPARATOR = new JavaNaturalComparator();
    034
    035    /*
    036     * (non-Javadoc)
    037     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
    038     */
    039    @Override
    040    public int compare(final String str1, final String str2 ) {
    041        if( Strings.CS.equals( str1, str2 ) ) {
    042            return 0; // the same object
    043        }
    044        if( str1 == null ) {
    045            return -1; // str1 is null and str2 isn't so str1 is smaller
    046        }
    047        if( str2 == null ) {
    048            return 1; // str2 is null and str1 isn't so str1 is bigger
    049        }
    050        return str1.compareTo( str2 );
    051    }
    052}