added ex X

src/exercises/ex_x/FamilyMember.java

@@ -0,0 +1,35 @@
+package exercises.ex_x;
+
+import exercises.Utils;
+
+import java.util.concurrent.Phaser;
+
+public class FamilyMember implements Runnable {
+    private final String name;
+    private final Phaser phaser;
+    private final int numSteps;
+
+    public FamilyMember(String name, Phaser phaser, int numSteps) {
+        this.name = name;
+        this.phaser = phaser;
+        this.numSteps = numSteps;
+        phaser.register();
+    }
+
+    @Override
+    public void run() {
+        int step = 0;
+        while (step < numSteps) {
+            step = phaser.getPhase() + 1;
+            try {
+                System.out.println(name + ": Step " + step + " started");
+                Utils.randomSleep(1000, 3000);
+                phaser.arriveAndAwaitAdvance();
+            } catch (InterruptedException e) {
+                break;
+            }
+        }
+        phaser.arriveAndDeregister();
+        System.out.println(name + " has arrived");
+    }
+}

src/exercises/ex_x/TestingPhaserFamilyBikeTrip.java

@@ -0,0 +1,24 @@
+package exercises.ex_x;
+
+import java.util.concurrent.Phaser;
+
+public class TestingPhaserFamilyBikeTrip {
+    public static void main(String[] args) {
+        String[] family = {"Father", "Mother", "Son", "Daughter_1", "Daughter_2"};
+        String[] routes = {"Sierre", "Sion", "Martigny", "St-Maurice", "Aigle", "Vevey"};
+        Phaser phaser = new Phaser();
+        phaser.register();
+
+        System.out.println("The family leaves Brig for a bike trip to Vevey");
+        for (int i = 0; i < family.length; i++) {
+            new Thread(new FamilyMember(family[i], phaser, routes.length)).start();
+        }
+
+        for (int i = 0; i < routes.length; i++) {
+            phaser.arriveAndAwaitAdvance();
+            System.out.println("All family members arrived to " + routes[i]);
+        }
+        phaser.arriveAndDeregister();
+        System.out.println("End of the bike trip.");
+    }
+}