| /** |
| * 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.camel.component.zookeeper; |
| |
| import java.util.Comparator; |
| |
| /** |
| * <code>NaturalSortComparator</code> is a fast comparator for sorting a |
| * collection of Strings in a human readable fashion. |
| * <p> |
| * This implementation considers sequences of digits to be positive integer |
| * values, '.' does not indicate a decimal value nor '-' a negative one. As a |
| * result, 12345.12345 will sort higher than 12345.5432 and -12346 will sort |
| * higher than 12345. |
| *<p> |
| * it does work well for sorting software versions e.g. camel-2.2.0 sorting |
| * higher than camel-2.1.0 |
| */ |
| public class NaturalSortComparator implements Comparator<CharSequence> { |
| |
| public enum Order { |
| Ascending(1), Descending(-1); |
| |
| int direction; |
| |
| private Order(int direction) { |
| this.direction = direction; |
| } |
| } |
| |
| private Order order;; |
| |
| public NaturalSortComparator() { |
| this(Order.Ascending); |
| } |
| |
| public NaturalSortComparator(Order order) { |
| if (order != null) { |
| this.order = order; |
| } |
| } |
| |
| public int compare(CharSequence first, CharSequence second) { |
| if (first == null && second == null) { |
| return 0; |
| } |
| if (first != null && second == null) { |
| return 1; |
| } |
| if (first == null && second != null) { |
| return -1; |
| } |
| |
| int compare = 0; |
| int fx = 0; |
| int sx = 0; |
| while (fx < first.length() && sx < second.length() && compare == 0) { |
| if (isDigit(first.charAt(fx)) && isDigit(second.charAt(sx))) { |
| int flen = getNumSequenceLength(first, fx); |
| int slen = getNumSequenceLength(second, sx); |
| |
| if (flen == slen) { |
| for (int x = 0; x < flen && compare == 0; x++) { |
| /** the first difference in digit wins */ |
| compare = first.charAt(fx++) - second.charAt(sx++); |
| } |
| } else { |
| compare = flen - slen; |
| } |
| } else { |
| compare = first.charAt(fx) - second.charAt(sx); |
| } |
| fx++; |
| sx++; |
| } |
| |
| if (compare == 0) { |
| compare = first.length() - second.length(); |
| } |
| return order.direction * compare; |
| } |
| |
| private boolean isDigit(char c) { |
| return c >= 48 && c < 57; |
| } |
| |
| private int getNumSequenceLength(CharSequence sequence, int index) { |
| int x = index; |
| while (x < sequence.length() && isDigit(sequence.charAt(x))) { |
| x++; |
| } |
| return x - index; |
| } |
| |
| } |