Stream API using

src/main/java/practice/CandidateValidator.java

@@ -1,5 +1,29 @@
 package practice;
 
-public class CandidateValidator {
-    //write your code here
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import model.Candidate;
+
+public class CandidateValidator implements Predicate<Candidate> {
+    private static final String NATIONALITY = "Ukrainian";
+    private static final String SEPARATOR_SYMBOL = "-";
+    private static final int MINIMUM_AGE_VALUE = 35;
+    private static final int MINIMUM_YEARS_IN_UKRAINE_VALUE = 10;
+    private static final int FIRST_ELEMENT_INDEX = 0;
+    private static final int LAST_ELEMENT_INDEX = 1;
+
+    @Override
+    public boolean test(Candidate candidate) {
+        return candidate.getAge() >= MINIMUM_AGE_VALUE
+                && candidate.isAllowedToVote()
+                && candidate.getNationality().equals(NATIONALITY)
+                && getYearsInUkraine(candidate) >= MINIMUM_YEARS_IN_UKRAINE_VALUE;
+    }
+
+    private int getYearsInUkraine(Candidate candidate) {
+        List<Integer> years = Arrays.stream(candidate.getPeriodsInUkr().split(SEPARATOR_SYMBOL))
+                .map(Integer::parseInt).toList();
+        return years.get(LAST_ELEMENT_INDEX) - years.get(FIRST_ELEMENT_INDEX);
+    }
 }

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.NoSuchElementException;
+import java.util.function.Function;
+import java.util.function.Predicate;
 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 NONE_MATCHES_MESSAGE = "Can't get min value from list: ";
+    private static final String NUMBERS_SEPARATOR_SYMBOL = ",";
+    private static final int HALF_DIVISER = 2;
+    private static final int REMINDER_DEFAULT = 0;
+
     public int findMinEvenNumber(List<String> numbers) {
-        return 0;
+        return numbers.stream()
+                .flatMap(stringNumber ->
+                        Arrays.stream(stringNumber.split(NUMBERS_SEPARATOR_SYMBOL)))
+                .mapToInt(Integer::parseInt)
+                .filter(numericValue -> numericValue % HALF_DIVISER == REMINDER_DEFAULT)
+                .min()
+                .orElseThrow(() ->
+                        new RuntimeException(NONE_MATCHES_MESSAGE + 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;
+        Function<Integer, Integer> oddSubstractFunction = integer -> {
+            int index = numbers.indexOf(integer);
+            int num = index % HALF_DIVISER != REMINDER_DEFAULT ? --integer : integer;
+            numbers.set(index, null);
+            return num;
+        };
+        return numbers.stream()
+                .map(oddSubstractFunction)
+                .filter(n -> n % HALF_DIVISER != REMINDER_DEFAULT)
+                .mapToDouble(Integer::doubleValue)
+                .average()
+                .orElseThrow(() -> new NoSuchElementException(""));
     }
 
-    /**
-     * 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.getSex().equals(Person.Sex.MAN)
+                        && fromAge <= person.getAge()
+                        && toAge >= person.getAge())
+                .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();
+        Predicate<Person> workableFilter = person -> fromAge <= person.getAge()
+                && ((person.getSex().equals(Person.Sex.WOMAN) && femaleToAge >= person.getAge())
+                || (person.getSex().equals(Person.Sex.MAN) && maleToAge >= person.getAge()));
+        return peopleList.stream()
+                .filter(workableFilter)
+                .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.getSex().equals(Person.Sex.WOMAN)
+                        && 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();
+        return candidates.stream()
+                .filter(candidate -> new CandidateValidator().test(candidate))
+                .map(Candidate::getName)
+                .sorted()
+                .toList();
     }
 }