write own impl of Predicate in CandidateValidator and implement metho…

src/main/java/practice/CandidateValidator.java

@@ -1,5 +1,63 @@
 package practice;
 
-public class CandidateValidator {
+import java.util.function.Predicate;
+import model.Candidate;
+
+public class CandidateValidator implements Predicate<Candidate> {
     //write your code here
+    private static final int MIN_ALLOWED_AGE = 35;
+    private static final String REQUIRED_NATIONALITY = "Ukrainian";
+    private static final int REQUIRED_YEARS_IN_UKR = 10;
+
+    @Override
+    public boolean test(Candidate candidate) {
+        if (candidate == null) {
+            return false;
+        }
+        if (candidate.getAge() < MIN_ALLOWED_AGE) {
+            return false;
+        }
+        if (!candidate.isAllowedToVote()) {
+            return false;
+        }
+        if (!REQUIRED_NATIONALITY.equals(candidate.getNationality())) {
+            return false;
+        }
+
+        String periods = candidate.getPeriodsInUkr();
+
+        if (periods == null || periods.trim().isEmpty()) {
+            return false;
+        }
+
+        int totalYears = 0;
+
+        String[] parts = periods.split(",");
+
+        for (String part : parts) {
+            String p = part.trim();
+            if (p.isEmpty()) {
+                continue;
+            }
+
+            String[] range = p.split("-");
+            if (range.length != 2) {
+                return false;
+            }
+
+            try {
+                int from = Integer.parseInt(range[0].trim());
+                int to = Integer.parseInt(range[1].trim());
+
+                if (to < from) {
+                    return false;
+                }
+
+                totalYears += (to - from + 1);
+            } catch (NumberFormatException e) {
+                return false;
+            }
+        }
+        return totalYears >= REQUIRED_YEARS_IN_UKR;
+    }
 }

src/main/java/practice/StreamPractice.java

@@ -1,8 +1,13 @@
 package practice;
 
-import java.util.Collections;
+import java.util.Arrays;
 import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import model.Candidate;
+import model.Cat;
 import model.Person;
 
 public class StreamPractice {
@@ -14,7 +19,15 @@ public class StreamPractice {
      * "Can't get min value from list: < Here is our input 'numbers' >"
      */
     public int findMinEvenNumber(List<String> numbers) {
-        return 0;
+        return numbers.stream()
+                .flatMap(s -> Arrays.stream(s.split(",")))
+                .map(String::trim)
+                .mapToInt(Integer::parseInt)
+                .filter(n -> n % 2 == 0)
+                .min()
+                .orElseThrow(() ->
+                        new RuntimeException("Can't get min value from list: " + numbers)
+                );
     }
 
     /**
@@ -23,7 +36,13 @@ public int findMinEvenNumber(List<String> numbers) {
      * But before that subtract 1 from each element on an odd position (having the odd index).
      */
     public Double getOddNumsAverage(List<Integer> numbers) {
-        return 0D;
+        return IntStream.range(0, numbers.size())
+                .map(i -> i % 2 == 1
+                        ? numbers.get(i) - 1
+                        : numbers.get(i))
+                .filter(n -> n % 2 != 0)
+                .average()
+                .orElseThrow(NoSuchElementException::new);
     }
 
     /**
@@ -35,7 +54,10 @@ public Double getOddNumsAverage(List<Integer> numbers) {
      * 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(p -> p.getSex() == Person.Sex.MAN && p.getAge() >= fromAge
+                        && p.getAge() <= toAge)
+                .collect(Collectors.toList());
     }
 
     /**
@@ -50,7 +72,11 @@ public List<Person> selectMenByAge(List<Person> peopleList, int fromAge, int toA
      */
     public List<Person> getWorkablePeople(int fromAge, int femaleToAge,
                                           int maleToAge, List<Person> peopleList) {
-        return Collections.emptyList();
+        return peopleList.stream()
+                .filter(p -> p.getAge() >= fromAge
+                        && ((p.getSex() == Person.Sex.WOMAN && p.getAge() <= femaleToAge)
+                        || (p.getSex() == Person.Sex.MAN && p.getAge() <= maleToAge)))
+                .collect(Collectors.toList());
     }
 
     /**
@@ -59,7 +85,12 @@ public List<Person> getWorkablePeople(int fromAge, int femaleToAge,
      * 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(p -> p.getSex() == Person.Sex.WOMAN && p.getAge() >= femaleAge)
+                .flatMap(p -> p.getCats().stream())
+                .map(Cat::getName)
+                .distinct()
+                .collect(Collectors.toList());
     }
 
     /**
@@ -75,6 +106,12 @@ public List<String> getCatsNames(List<Person> peopleList, int femaleAge) {
      * parametrized with Candidate in CandidateValidator.
      */
     public List<String> validateCandidates(List<Candidate> candidates) {
-        return Collections.emptyList();
+        Predicate<Candidate> validator = new CandidateValidator();
+
+        return candidates.stream()
+                .filter(validator)
+                .map(Candidate::getName)
+                .sorted()
+                .collect(Collectors.toList());
     }
 }