jv-stream-github-practice-01

src/main/java/practice/CandidateValidator.java

@@ -1,5 +1,25 @@
 package practice;
 
-public class CandidateValidator {
-    //write your code here
+import java.util.Arrays;
+import java.util.function.Predicate;
+import model.Candidate;
+
+public class CandidateValidator implements Predicate<Candidate> {
+    private static final int MIN_AGE = 35;
+    private static final int REQUIRED_YEARS = 10;
+
+    @Override
+    public boolean test(Candidate candidate) {
+        return candidate.getAge() >= MIN_AGE
+                && candidate.isAllowedToVote()
+                && "Ukrainian".equalsIgnoreCase(candidate.getNationality())
+                && hasLivedInUkraineFor10Years(candidate.getPeriodsInUkr());
+    }
+
+    private boolean hasLivedInUkraineFor10Years(String periodsInUkr) {
+        return Arrays.stream(periodsInUkr.split(","))
+                .map(period -> period.split("-"))
+                .mapToInt(years -> Integer.parseInt(years[1]) - Integer.parseInt(years[0]))
+                .sum() >= REQUIRED_YEARS;
+    }
 }

src/main/java/practice/StreamPractice.java

@@ -1,29 +1,50 @@
 package practice;
 
-import java.util.Collections;
+import java.util.Arrays;
 import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 import model.Candidate;
+import model.Cat;
 import model.Person;
 
 public class StreamPractice {
+    private static final int MinAge = 35;
+
     /**
      * 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' >"
      */
+
     public int findMinEvenNumber(List<String> numbers) {
-        return 0;
+        return numbers.stream()
+                .flatMap(line -> Arrays.stream(line.split(",")))
+                .map(Integer::parseInt)
+                .filter(n -> n % 2 == 0)
+                .min(Integer::compare)
+                .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;
+        return IntStream.range(0, numbers.size())
+                .map(index -> (index % 2 != 0)
+                        ? numbers.get(index) - 1
+                        : numbers.get(index))
+                .filter(n -> n % 2 != 0)
+                .average()
+                .orElseThrow(()
+                        -> new NoSuchElementException("Can't get min value from list: " + numbers));
     }
 
     /**
@@ -34,8 +55,14 @@ public Double getOddNumsAverage(List<Integer> numbers) {
      * <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(p -> p.getSex()
+                        .equals(Person.Sex.MAN)
+                        && p.getAge() >= fromAge
+                        && p.getAge() <= toAge)
+                .collect(Collectors.toList());
     }
 
     /**
@@ -48,18 +75,30 @@ public List<Person> selectMenByAge(List<Person> peopleList, int fromAge, int toA
      * 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(p -> p.getAge() >= fromAge
+                        && (p.getSex().equals(Person.Sex.MAN)
+                        && p.getAge() <= maleToAge || p.getSex().equals(Person.Sex.WOMAN)
+                        && p.getAge() <= femaleToAge))
+                .collect(Collectors.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(pw -> pw.getSex()
+                        .equals(Person.Sex.WOMAN) && pw.getAge() > femaleAge)
+                .flatMap(person -> person.getCats().stream())
+                .map(Cat::getName)
+                .collect(Collectors.toList());
     }
 
     /**
@@ -74,7 +113,13 @@ public List<String> getCatsNames(List<Person> peopleList, int femaleAge) {
      * 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 candidateValidator = new CandidateValidator();
+        return candidates.stream()
+                .filter(candidateValidator)
+                .map(Candidate::getName)
+                .sorted()
+                .collect(Collectors.toList());
     }
 }