помогите разобраться с ним
package com.javarush.task.task33.task3310;
import com.javarush.task.task33.task3310.strategy.HashMapStorageStrategy;
import com.javarush.task.task33.task3310.strategy.StorageStrategy;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
public class Solution {
public static Set<Long> getIds(Shortener shortener, Set<String> strings) {
Set<Long> ids = new HashSet<>();
for (String s : strings) { ids.add(shortener.getId(s)); }
return ids;
}
public static Set<String> getStrings(Shortener shortener, Set<Long> keys) {
Set<String> strings = new HashSet<>();
for (Long key : keys) { strings.add(shortener.getString(key)); }
return strings;
}
public static void testStrategy(StorageStrategy strategy, long elementsNumber) {
Helper.printMessage(strategy.getClass().getSimpleName());
Set<String> strings = new HashSet<>();
for (long i = 0; i < elementsNumber; i++) {
strings.add(Helper.generateRandomString());
}
Shortener shortener = new Shortener(strategy);
Long time1 = new Date().getTime();
Set<Long> keys = getIds(shortener, strings);
Long time2 = new Date().getTime();
Long duration = time2 - time1;
Helper.printMessage(duration.toString());
Long time3 = new Date().getTime();
Set<String> testSet = getStrings(shortener, keys);
Long time4 = new Date().getTime();
Long duration2 = time4 - time3;
Helper.printMessage(duration2.toString());
if (testSet.equals(strings)) Helper.printMessage("Тест пройден.");
else Helper.printMessage("Тест не пройден.");
}
public static void main(String[] args) {
StorageStrategy strategy1 = new HashMapStorageStrategy();
testStrategy(strategy1, 10000);
}
}