JAVA code to handle versions and the comparisons.

Hello Buddies.

Sharing a small but useful piece of code, that can help you in handling version strings and comparisons in day-to-day coding.

Many a time, we struggle while comparing and transcoding the versions, which might take some time and can be frustrating as well.

So for my reference, I am keeping this snippet handy, and so is for you.

Check out the full project here, OR you may refer to the code shared below.


Happy Coding!

 package versionCheckDemo;  
 /**  
  * @author namit  
  * @version 2.0  
  *   
  * re-checking-in for testing develop branch  
  *   
  * */  
 public class VersionTester {  
  public static void main(String[] args) {  
   System.out.println("Part 1 - Generalize the version numbers to a standard format - a.b.c");  
   String input = "1.1";  
   update(input);  
   input = "1.1.1";  
   update(input);  
   input = "1";  
   update(input);  
   System.out.println("Part 2 - Get the main digit representing the version number ");  
   input = "1.0.1";  
   findVersion(input);  
   input = "54.1";  
   findVersion(input);  
   input = "100";  
   findVersion(input);  
   input = "100.c.c";  
   findVersion(input);  
   input = "100.cc.&@!#$$";  
   findVersion(input);  
   System.out.println("Part 3 - Comparing the versions, under the format a.b.c ");  
   String versionX = "2.3";  
   String minVersion = "2.5.5";  
   checkVersion(versionX, minVersion);  
   versionX = "2.7.9";  
   minVersion = "2.5.5";  
   checkVersion(versionX, minVersion);  
  }  
  /**  
   * Method to update the version numbers to a uniform pattern  
   * */  
  private static void update(String input) {  
   System.out.println("incoming >> " + input);  
   int occurence = countMatches(input, '.');  
   if (occurence == 0)  
    input += ".0.0";  
   else if (occurence == 1)  
    input += ".0";  
   System.out.println("outgoing >> " + input);  
   System.out.println("---------------");  
  }  
  public static int countMatches(final CharSequence str, final char ch) {  
   if (null == str) {  
    return 0;  
   }  
   int count = 0;  
   char[] arr = ((String) str).toCharArray();  
   for (char c : arr) {  
    if (c == ch)  
     count++;  
   }  
   // likewise you can go for  
   // org.apache.commons.lang3.StringUtils.StringUtils.countMatches(str, ch)  
   // for saving time of writing the count logic  
   return count;  
  }  
  /**  
   * Method to find the main version number  
   * */  
  private static void findVersion(String input) {  
   System.out.println("Incoming >> " + input);  
   String inputWithoutDots = input.replace(".", "");  
   if (inputWithoutDots.matches("[0-9]+")) {  
    int version = 0;  
    String[] arr = input.split("\\.");  
    version = Integer.valueOf(arr[0]);  
    System.out.println("Success! outgoing >> " + version);  
   } else {  
    System.out.println("error!");  
   }  
   System.out.println("---------------");  
  }  
  /**  
   * Method to compare the given version with a minimum accepted version  
   * */  
  private static void checkVersion(String versionX, String minVersion) {  
   String minVersionFormatted = String.format("%-4s", minVersion.replace(".", "")).replace(' ', '0');  
   int minVersionNum = Integer.valueOf(minVersionFormatted);  
   String formattedVersion = String.format("%-4s", versionX.replace(".", "")).replace(' ', '0');  
   int versionXNum = Integer.parseInt(formattedVersion);  
   System.out.println("Min Version - "+minVersion);  
   System.out.println("You provided - "+versionX);  
   if (versionXNum >= minVersionNum) {  
    System.out.println("Version Accepted!");  
   } else {  
    System.out.println("Version Rejected!");  
   }  
   System.out.println("---------------");  
  }  
 }  

OUTPUT:

 Part 1 - Generalize the version numbers to a standard format - a.b.c  
 incoming >> 1.1  
 outgoing >> 1.1.0  
 ---------------  
 incoming >> 1.1.1  
 outgoing >> 1.1.1  
 ---------------  
 incoming >> 1  
 outgoing >> 1.0.0  
 ---------------  
 Part 2 - Get the main digit representing the version number   
 Incoming >> 1.0.1  
 Success! outgoing >> 1  
 ---------------  
 Incoming >> 54.1  
 Success! outgoing >> 54  
 ---------------  
 Incoming >> 100  
 Success! outgoing >> 100  
 ---------------  
 Incoming >> 100.c.c  
 error!  
 ---------------  
 Incoming >> 100.cc.&@!#$$  
 error!  
 ---------------  
 Part 3 - Comparing the versions, under the format a.b.c   
 Min Version - 2.5.5  
 You provided - 2.3  
 Version Rejected!  
 ---------------  
 Min Version - 2.5.5  
 You provided - 2.7.9  
 Version Accepted!  
 ---------------