docs: update throttling

throttling/README.md

@@ -39,7 +39,6 @@ In this example a young human and an old dwarf walk into a bar. They start order
 `BarCustomer` class presents the clients of the `Bartender` API. `CallsCount` tracks the number of calls per `BarCustomer`.
 
 ```java
-
 @Getter
 public class BarCustomer {
 
@@ -55,7 +54,9 @@ public class BarCustomer {
         callsCount.addTenant(name);
     }
 }
+```
 
+```java
 @Slf4j
 public final class CallsCount {
     private final Map<String, AtomicLong> tenantCallsCount = new ConcurrentHashMap<>();
@@ -85,7 +86,9 @@ Next, the service that the tenants are calling is introduced. To track the call
 public interface Throttler {
     void start();
 }
+```
 
+```java
 public class ThrottleTimerImpl implements Throttler {
 
     private final int throttlePeriod;
@@ -142,36 +145,42 @@ class Bartender {
 Now it is possible to see the full example in action. `BarCustomer` young human is rate-limited to 2 calls per second and the old dwarf to 4.
 
 ```java
-public static void main(String[] args) {
-    var callsCount = new CallsCount();
-    var human = new BarCustomer("young human", 2, callsCount);
-    var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
+@Slf4j
+public class App {
 
-    var executorService = Executors.newFixedThreadPool(2);
+    public static void main(String[] args) {
+        var callsCount = new CallsCount();
+        var human = new BarCustomer("young human", 2, callsCount);
+        var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
 
-    executorService.execute(() -> makeServiceCalls(human, callsCount));
-    executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
+        var executorService = Executors.newFixedThreadPool(2);
 
-    executorService.shutdown();
-    try {
-        executorService.awaitTermination(10, TimeUnit.SECONDS);
-    } catch (InterruptedException e) {
-        LOGGER.error("Executor service terminated: {}", e.getMessage());
-    }
-}
+        executorService.execute(() -> makeServiceCalls(human, callsCount));
+        executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
 
-private static void makeServiceCalls(BarCustomer barCustomer, CallsCount callsCount) {
-    var timer = new ThrottleTimerImpl(1000, callsCount);
-    var service = new Bartender(timer, callsCount);
-    // Sleep is introduced to keep the output in check and easy to view and analyze the results.
-    IntStream.range(0, 50).forEach(i -> {
-        service.orderDrink(barCustomer);
+        executorService.shutdown();
         try {
-            Thread.sleep(100);
+            if (!executorService.awaitTermination(10, TimeUnit.SECONDS)) {
+                executorService.shutdownNow();
+            }
         } catch (InterruptedException e) {
-            LOGGER.error("Thread interrupted: {}", e.getMessage());
+            executorService.shutdownNow();
         }
-    });
+    }
+
+    private static void makeServiceCalls(BarCustomer barCustomer, CallsCount callsCount) {
+        var timer = new ThrottleTimerImpl(1000, callsCount);
+        var service = new Bartender(timer, callsCount);
+        // Sleep is introduced to keep the output in check and easy to view and analyze the results.
+        IntStream.range(0, 50).forEach(i -> {
+            service.orderDrink(barCustomer);
+            try {
+                Thread.sleep(100);
+            } catch (InterruptedException e) {
+                LOGGER.error("Thread interrupted: {}", e.getMessage());
+            }
+        });
+    }
 }
 ```
 
@@ -202,10 +211,6 @@ An excerpt from the example's console output:
 18:46:37.148 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
 ```
 
-## Class diagram
-
-![Throttling](./etc/throttling_urm.png "Throttling pattern class diagram")
-
 ## Applicability
 
 * You need to protect resources from being overwhelmed by too many requests.
@@ -239,5 +244,5 @@ Trade-offs:
 
 ## Credits
 
-* [Throttling pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/throttling)
-* [Cloud Design Patterns: Prescriptive Architecture Guidance for Cloud Applications (Microsoft patterns & practices)](https://www.amazon.com/gp/product/B00ITGHBBS/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=B00ITGHBBS&linkId=12aacdd0cec04f372e7152689525631a)
+* [Throttling pattern (Microsoft)](https://docs.microsoft.com/en-us/azure/architecture/patterns/throttling)
+* [Cloud Design Patterns: Prescriptive Architecture Guidance for Cloud Applications](https://amzn.to/4dLvowg)