Solution for Generics 03

Exercise.java

@@ -1,6 +1,20 @@
+import java.util.ArrayList;
+
 public class Exercise {
 
   public static void main(String[] args) {
-    // implement exercise here
+
+    SchoolClass schoolClass = new SchoolClass("9c", new ArrayList<>());
+
+    schoolClass.addPupil(new Pupil("Hans", "m"));
+    schoolClass.addPupil(new Pupil("Peter", "m"));
+    schoolClass.addPupil(new Pupil("Lisa", "w"));
+    schoolClass.addPupil(new Pupil("Fritz", "m"));
+    schoolClass.addPupil(new Pupil("Max", "m"));
+    schoolClass.addPupil(new Pupil("Franziska", "w"));
+    schoolClass.addPupil(new Pupil("Jennifer", "w"));
+    // schoolClass.addPupil(new Pupil("Jeremy", "m"));
+
+    schoolClass.getPairs().forEach(System.out::println);
   }
 }

Pair.java

@@ -0,0 +1 @@
+public record Pair<T>(T partA, T partB) {}

Pupil.java

@@ -0,0 +1 @@
+public record Pupil(String name, String gender) {}

SchoolClass.java

@@ -0,0 +1,27 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public record SchoolClass(String name, List<Pupil> pupils) {
+
+  public void addPupil(Pupil pupil) {
+    pupils.add(pupil);
+  }
+
+  public List<Pair<Pupil>> getPairs() {
+    List<Pair<Pupil>> pairs = new ArrayList<>();
+    while (pupils().size() > 0) {
+      if (pupils.size() == 1) {
+        pairs.add(new Pair<Pupil>(pupils().get(0), null));
+        pupils().clear();
+      } else {
+        Pupil single1 = pupils.get((new Random().nextInt(pupils.size())));
+        pupils.remove(single1);
+        Pupil single2 = pupils.get((new Random().nextInt(pupils.size())));
+        pupils.remove(single2);
+        pairs.add(new Pair<Pupil>(single1, single2));
+      }
+    }
+    return pairs;
+  }
+}