Added example of a route with an optional id query parameter

app/controllers/ExamplesController.java

@@ -7,6 +7,9 @@ import play.libs.Json;
 import play.mvc.Controller;
 import play.mvc.Result;
 
+import java.util.Optional;
+import java.util.Random;
+
 /**
  * This controller contains an action to handle HTTP requests
  * to the application's home page.
@@ -44,4 +47,30 @@ public class ExamplesController extends Controller {
 
     }
 
+    private String chars = "abcdefghijklmnopqrstuvwxyz0123456789";
+
+    private Random random = new Random(System.currentTimeMillis());
+
+    /**
+     * Generates an 8 character random string
+     * @return
+     */
+    private String randomId() {
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < 8; i++) {
+            int idx = random.nextInt(chars.length());
+            sb.append(chars.charAt(idx));
+        }
+        return sb.toString();
+    }
+
+
+    public Result game(String id) {
+        if (id != null) {
+            return ok("The id was " + id);
+        } else {
+            return redirect("/example/game?id=" + randomId());
+        }
+    }
+
 }

conf/routes

@@ -8,5 +8,7 @@ GET     /                           controllers.HomeController.index
 GET     /example/json               controllers.ExamplesController.returnJson()
 POST    /example/json               controllers.ExamplesController.receiveJsonPost()
 
+GET     /example/game               controllers.ExamplesController.game(id ?= null)
+
 # Map static resources from the /public folder to the /assets URL path
 GET     /assets/*file               controllers.Assets.versioned(path="/public", file: Asset)