implemented all methods of StreamPractice according to task

src/main/java/practice/CandidateValidator.java

@@ -1,5 +1,30 @@
 package practice;
 
-public class CandidateValidator {
-    //write your code here
+import java.util.function.Predicate;
+import model.Candidate;
+
+public class CandidateValidator implements Predicate<Candidate> {
+    private static final int MIN_AGE = 35;
+    private static final String REQUIRED_NATIONALITY = "Ukrainian";
+    private static final String SPLIT_REGEX = "-";
+    private static final int MIN_PERIOD_OF_LIVING = 10;
+    private static final int LIVE_FROM = 0;
+    private static final int LIVE_TO = 1;
+
+    @Override
+    public boolean test(Candidate candidate) {
+        boolean isAgeAllowed = candidate.getAge() >= MIN_AGE;
+        boolean isAllowedToVote = candidate.isAllowedToVote();
+        boolean isNationalityAllowed = candidate.getNationality().equals(REQUIRED_NATIONALITY);
+        boolean hasTenYearsInUkraine = getYearsInUkraine(candidate.getPeriodsInUkr());
+
+        return isAgeAllowed && isNationalityAllowed && isAllowedToVote && hasTenYearsInUkraine;
+    }
+
+    private boolean getYearsInUkraine(String period) {
+        String[] periodLength = period.split(SPLIT_REGEX);
+        int yearsInUkraine = Integer.parseInt(periodLength[LIVE_TO])
+                - Integer.parseInt(periodLength[LIVE_FROM]);
+        return yearsInUkraine >= MIN_PERIOD_OF_LIVING;
+    }
 }

src/main/java/practice/StreamPractice.java

@@ -1,80 +1,77 @@
 package practice;
 
-import java.util.Collections;
+import java.util.Arrays;
 import java.util.List;
+import java.util.stream.IntStream;
 import model.Candidate;
+import model.Cat;
 import model.Person;
 
 public class StreamPractice {
-    /**
-     * Given list of strings where each element contains 1+ numbers:
-     * input = {"5,30,100", "0,22,7", ...}
-     * return min integer value. One more thing - we're interested in even numbers.
-     * If there is no needed data throw RuntimeException with message
-     * "Can't get min value from list: < Here is our input 'numbers' >"
-     */
+    private static final String SPLIT_STRING_REGEX = ",";
+
     public int findMinEvenNumber(List<String> numbers) {
-        return 0;
+        return numbers.stream()
+                .map(string -> string.split(SPLIT_STRING_REGEX))
+                .flatMap(Arrays::stream)
+                .mapToInt(Integer::parseInt)
+                .filter(this::isEven)
+                .min()
+                .orElseThrow(() -> new RuntimeException("Can't get min value from list: "
+                        + numbers));
     }
 
-    /**
-     * Given a List of Integer numbers,
-     * return the average of all odd numbers from the list or throw NoSuchElementException.
-     * But before that subtract 1 from each element on an odd position (having the odd index).
-     */
     public Double getOddNumsAverage(List<Integer> numbers) {
-        return 0D;
+        System.out.println(numbers);
+        return IntStream.range(0, numbers.size())
+                .map(index -> isEven(index) ? numbers.get(index) : numbers.get(index) - 1)
+                .filter(number -> !isEven(number))
+                .average()
+                .getAsDouble();
     }
 
-    /**
-     * Given a List of `Person` instances (having `name`, `age` and `sex` fields),
-     * for example, `Arrays.asList( new Person(«Victor», 16, Sex.MAN),
-     * new Person(«Helen», 42, Sex.WOMAN))`,
-     * select from the List only men whose age is from `fromAge` to `toAge` inclusively.
-     * <p>
-     * Example: select men who can be recruited to army (from 18 to 27 years old inclusively).
-     */
     public List<Person> selectMenByAge(List<Person> peopleList, int fromAge, int toAge) {
-        return Collections.emptyList();
+        return peopleList.stream()
+                .filter(person -> Person.Sex.MAN.equals(person.getSex())
+                        && person.getAge() >= fromAge && person.getAge() <= toAge)
+                .toList();
     }
 
-    /**
-     * Given a List of `Person` instances (having `name`, `age` and `sex` fields),
-     * for example, `Arrays.asList( new Person(«Victor», 16, Sex.MAN),
-     * new Person(«Helen», 42, Sex.WOMAN))`,
-     * select from the List only people whose age is from `fromAge` and to `maleToAge` (for men)
-     * or to `femaleToAge` (for women) inclusively.
-     * <p>
-     * Example: select people of working age
-     * (from 18 y.o. and to 60 y.o. for men and to 55 y.o. for women inclusively).
-     */
     public List<Person> getWorkablePeople(int fromAge, int femaleToAge,
                                           int maleToAge, List<Person> peopleList) {
-        return Collections.emptyList();
+        return peopleList.stream()
+                .filter(person -> validatePerson(person, fromAge, maleToAge, femaleToAge))
+                .toList();
     }
 
-    /**
-     * Given a List of `Person` instances (having `name`, `age`, `sex` and `cats` fields,
-     * and each `Cat` having a `name` and `age`),
-     * return the names of all cats whose owners are women from `femaleAge` years old inclusively.
-     */
     public List<String> getCatsNames(List<Person> peopleList, int femaleAge) {
-        return Collections.emptyList();
+        return peopleList.stream()
+                .filter(person -> Person.Sex.WOMAN.equals(person.getSex())
+                        && person.getAge() >= femaleAge)
+                .flatMap(person -> person.getCats().stream())
+                .map(Cat::getName)
+                .toList();
     }
 
-    /**
-     * Your help with a election is needed. Given list of candidates, where each element
-     * has Candidate.class type.
-     * Check which candidates are eligible to apply for president position and return their
-     * names sorted alphabetically.
-     * The requirements are: person should be older than 35 years, should be allowed to vote,
-     * have nationality - 'Ukrainian'
-     * and live in Ukraine for 10 years. For the last requirement use field periodsInUkr,
-     * which has following view: "2002-2015"
-     * We want to reuse our validation in future, so let's write our own impl of Predicate
-     * parametrized with Candidate in CandidateValidator.
-     */
     public List<String> validateCandidates(List<Candidate> candidates) {
-        return Collections.emptyList();
+        CandidateValidator validator = new CandidateValidator();
+        return candidates.stream()
+                .filter(validator)
+                .map(Candidate::getName)
+                .sorted()
+                .toList();
+    }
+
+    private boolean validatePerson(Person person, int fromAge, int maleToAge, int femaleToAge) {
+        int age = person.getAge();
+        Person.Sex sex = person.getSex();
+        return Person.Sex.MAN.equals(sex)
+                && age >= fromAge && age <= maleToAge
+                || Person.Sex.WOMAN.equals(sex)
+                && age >= fromAge && age <= femaleToAge;
+    }
+
+    private boolean isEven(int number) {
+        return number % 2 == 0;
     }
 }