Is there something wrong with my logic? Because it does what the requirements are.

Question about the task

Resolved

I have even compared it to the solution , and they seem quite similar in output. Maybe I am missing something?

You must implement the rollback method in the Software class. It should make it possible to roll back the current software version to the desired version. All versions after the one we roll back to must be removed. And don't forget to change the currentVersion field.
The rollback method should return true if everything succeeds and false if the desired version is not found.

Requirements:

The rollback method should return false if the desired version is not found in versionHistoryMap.
The rollback method should only remove from versionHistoryMap software versions that follow the one passed as an argument.
The rollback method should set currentVersion to a new value and return true if the rollback is successful.
If the rollback is not possible, then the rollback method must not change currentVersion and versionHistoryMap.

package com.codegym.task.task39.task3911; import java.util.Map; /* Rollback */ public class Solution { public static void main(String[] args) { Software software = new Software(); int n = 3; for (int i = 1; i < 7; i++) { software.addNewVersion(i, "Description of version #" + i); } System.out.println("Printing all versions "); for (Map.Entry entry : software.getVersionHistoryMap().entrySet()) { System.out.println(entry.getKey() + " :: " + entry.getValue()); } System.out.println("The current version is " + software.getCurrentVersion()); System.out.println("ROLLING BACK to version " + n); software.rollback(n); System.out.println("\nPrinting all versions "); for (Map.Entry entry : software.getVersionHistoryMap().entrySet()) { System.out.println(entry.getKey() + " :: " + entry.getValue()); } System.out.println("The current version is " + software.getCurrentVersion()); } }

Comments (2)

Popular
New
Old

You must be signed in to leave a comment

Guadalupe Gagnon

Level 37 , Tampa, United States

2 August 2021, 14:19

solution

This code assumes that the versions are ordered so that each new version is just 1 more than the last version (e.g. 1, 2, 3, 4, 5, etc). That may not be the case and the version numbers could increase in unique intervals (e.g 1, 3, 7, 8, 15, etc). I would code it expecting that to be the case instead of the "clean" version. The limit variable would not be calculated correctly if they were not in order. You can see this if you changed the loop in the main() method that enters the versions to:

for (int i = 1; i < 15; i += 2) {
   software.addNewVersion(i, "Description of version #" + i);
}

A tip: Line 35 is redundant. You check if the the map contains the version at line 37. If it does then it enters the if block and returns true. If it is not contained then line 45 will return false. There is not need for line 35. Alternatively you could remove lines 37, 44, and 45 if you wanted to keep line 35.

Andrei

Level 41

2 August 2021, 14:43

Ah, OK, I did not think of that scenario, thanks! Indeed, the solution proposed by mentor makes a keyset and adds the keys to a list and then just removes those items. Cool