| /* |
| * Copyright 2012-present Facebook, Inc. |
| * |
| * Licensed 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 com.facebook.buck.util; |
| |
| import java.util.Comparator; |
| import java.util.regex.Pattern; |
| |
| /** |
| * Compares version strings such as "4.2.2" and "17.0". |
| */ |
| public class VersionStringComparator implements Comparator<String> { |
| |
| private static final Pattern VERSION_STRING_PATTERN = Pattern.compile("(\\d+)(\\.\\d+)*?"); |
| |
| public static boolean isValidVersionString(String str) { |
| return VERSION_STRING_PATTERN.matcher(str).matches(); |
| } |
| |
| @Override |
| public int compare(String a, String b) { |
| if (!isValidVersionString(a)) { |
| throw new RuntimeException("Invalid version string: " + a); |
| } |
| |
| if (!isValidVersionString(b)) { |
| throw new RuntimeException("Invalid version string: " + b); |
| } |
| |
| String[] partsA = a.split("\\."); |
| String[] partsB = b.split("\\."); |
| |
| for (int i = 0; i < partsA.length; i++) { |
| if (i >= partsB.length) { |
| return 1; |
| } |
| |
| String partA = partsA[i]; |
| String partB = partsB[i]; |
| |
| int valueA = Integer.parseInt(partA); |
| int valueB = Integer.parseInt(partB); |
| int delta = valueA - valueB; |
| if (delta != 0) { |
| return delta; |
| } |
| } |
| |
| if (partsA.length == partsB.length) { |
| return 0; |
| } else { |
| return -1; |
| } |
| } |
| } |