com.spotify.docker.client.VersionCompare Maven / Gradle / Ivy
/*-
* -\-\-
* docker-client
* --
* Copyright (C) 2016 Spotify AB
* Copyright (c) 2015 Jeppe Schou
* --
* 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.spotify.docker.client;
public final class VersionCompare {
private VersionCompare() {
}
/**
* Compares two version strings.
*
* https://stackoverflow.com/questions/6701948/efficient-way-to-compare-version-strings-in-java
*
*
Use this instead of String.compareTo() for a non-lexicographical comparison that works for
* version strings. e.g. "1.10".compareTo("1.6").
*
* @param str1 a string of ordinal numbers separated by decimal points.
* @param str2 a string of ordinal numbers separated by decimal points.
* @return The result is a negative integer if str1 is _numerically_ less than str2. The result is
* a positive integer if str1 is _numerically_ greater than str2. The result is zero if
* the strings are _numerically_ equal. N.B. It does not work if "1.10" is supposed to be
* equal to "1.10.0".
*/
public static int compareVersion(final String str1, final String str2) {
final String[] vals1 = str1.split("\\.");
final String[] vals2 = str2.split("\\.");
int idx = 0;
// set index to first non-equal ordinal or length of shortest version string
while (idx < vals1.length && idx < vals2.length && vals1[idx].equals(vals2[idx])) {
idx++;
}
// compare first non-equal ordinal number
if (idx < vals1.length && idx < vals2.length) {
final int diff = Integer.valueOf(vals1[idx]).compareTo(Integer.valueOf(vals2[idx]));
return Integer.signum(diff);
} else {
// the strings are equal or one string is a substring of the other
// e.g. "1.2.3" = "1.2.3" or "1.2.3" < "1.2.3.4"
return Integer.signum(vals1.length - vals2.length);
}
}
}