delete unwanted files

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>

.all-contributorsrc

@@ -1749,6 +1749,33 @@
         "review",
         "code"
       ]
+    },
+    {
+      "login": "interactwithankush",
+      "name": "interactwithankush",
+      "avatar_url": "https://avatars.githubusercontent.com/u/18613127?v=4",
+      "profile": "https://github.com/interactwithankush",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "yuhangbin",
+      "name": "CharlieYu",
+      "avatar_url": "https://avatars.githubusercontent.com/u/17566866?v=4",
+      "profile": "https://github.com/yuhangbin",
+      "contributions": [
+        "code"
+      ]
+    },
+    {
+      "login": "Leisterbecker",
+      "name": "Leisterbecker",
+      "avatar_url": "https://avatars.githubusercontent.com/u/20650323?v=4",
+      "profile": "https://github.com/Leisterbecker",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 7,

README.md

@@ -10,7 +10,7 @@
 [![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
 [![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-192-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-195-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->
 
 <br/>
@@ -322,6 +322,9 @@ This project is licensed under the terms of the MIT license.
     <td align="center"><a href="https://www.linkedin.com/in/abhinav-vashisth-06613b208/"><img src="https://avatars.githubusercontent.com/u/89785800?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Abhinav Vashisth</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vashisthabhinav" title="Documentation">📖</a></td>
     <td align="center"><a href="http://no website"><img src="https://avatars.githubusercontent.com/u/47126749?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kevin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AKevinyl3" title="Reviewed Pull Requests">👀</a></td>
     <td align="center"><a href="https://github.com/Shrirang97"><img src="https://avatars.githubusercontent.com/u/28738668?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shrirang</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AShrirang97" title="Reviewed Pull Requests">👀</a> <a href="https://github.com/iluwatar/java-design-patterns/commits?author=Shrirang97" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/interactwithankush"><img src="https://avatars.githubusercontent.com/u/18613127?v=4?s=100" width="100px;" alt=""/><br /><sub><b>interactwithankush</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=interactwithankush" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/yuhangbin"><img src="https://avatars.githubusercontent.com/u/17566866?v=4?s=100" width="100px;" alt=""/><br /><sub><b>CharlieYu</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yuhangbin" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/Leisterbecker"><img src="https://avatars.githubusercontent.com/u/20650323?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Leisterbecker</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Leisterbecker" title="Code">💻</a></td>
   </tr>
 </table>
 

event-aggregator/src/main/java/com/iluwatar/event/aggregator/App.java

@@ -49,13 +49,28 @@ public class App {
   public static void main(String[] args) {
 
     var kingJoffrey = new KingJoffrey();
-    var kingsHand = new KingsHand(kingJoffrey);
+
+    var kingsHand = new KingsHand();
+    kingsHand.registerObserver(kingJoffrey, Event.TRAITOR_DETECTED);
+    kingsHand.registerObserver(kingJoffrey, Event.STARK_SIGHTED);
+    kingsHand.registerObserver(kingJoffrey, Event.WARSHIPS_APPROACHING);
+    kingsHand.registerObserver(kingJoffrey, Event.WHITE_WALKERS_SIGHTED);
+
+    var varys = new LordVarys();
+    varys.registerObserver(kingsHand, Event.TRAITOR_DETECTED);
+    varys.registerObserver(kingsHand, Event.WHITE_WALKERS_SIGHTED);
+
+    var scout = new Scout();
+    scout.registerObserver(kingsHand, Event.WARSHIPS_APPROACHING);
+    scout.registerObserver(varys, Event.WHITE_WALKERS_SIGHTED);
+
+    var baelish = new LordBaelish(kingsHand, Event.STARK_SIGHTED);
 
     var emitters = List.of(
         kingsHand,
-        new LordBaelish(kingsHand),
-        new LordVarys(kingsHand),
-        new Scout(kingsHand)
+        baelish,
+        varys,
+        scout
     );
 
     Arrays.stream(Weekday.values())

event-aggregator/src/main/java/com/iluwatar/event/aggregator/Event.java

@@ -31,6 +31,7 @@ import lombok.RequiredArgsConstructor;
 @RequiredArgsConstructor
 public enum Event {
 
+  WHITE_WALKERS_SIGHTED("White walkers sighted"),
   STARK_SIGHTED("Stark sighted"),
   WARSHIPS_APPROACHING("Warships approaching"),
   TRAITOR_DETECTED("Traitor detected");

event-aggregator/src/main/java/com/iluwatar/event/aggregator/EventEmitter.java

@@ -23,31 +23,48 @@
 
 package com.iluwatar.event.aggregator;
 
+import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Map;
 
 /**
  * EventEmitter is the base class for event producers that can be observed.
  */
 public abstract class EventEmitter {
 
-  private final List<EventObserver> observers;
+  private final Map<Event, List<EventObserver>> observerLists;
 
   public EventEmitter() {
-    observers = new LinkedList<>();
+    observerLists = new HashMap<>();
   }
 
-  public EventEmitter(EventObserver obs) {
+  public EventEmitter(EventObserver obs, Event e) {
     this();
-    registerObserver(obs);
+    registerObserver(obs, e);
   }
 
-  public final void registerObserver(EventObserver obs) {
-    observers.add(obs);
+  /**
+  * Registers observer for specific event in the related list.
+  *
+  * @param obs the observer that observers this emitter
+  * @param e the specific event for that observation occurs
+  * */
+  public final void registerObserver(EventObserver obs, Event e) {
+    if (!observerLists.containsKey(e)) {
+      observerLists.put(e, new LinkedList<>());
+    }
+    if (!observerLists.get(e).contains(obs)) {
+      observerLists.get(e).add(obs);
+    }
   }
 
   protected void notifyObservers(Event e) {
-    observers.forEach(obs -> obs.onEvent(e));
+    if (observerLists.containsKey(e)) {
+      observerLists
+        .get(e)
+        .forEach(observer -> observer.onEvent(e));
+    }
   }
 
   public abstract void timePasses(Weekday day);

event-aggregator/src/main/java/com/iluwatar/event/aggregator/KingsHand.java

@@ -31,8 +31,8 @@ public class KingsHand extends EventEmitter implements EventObserver {
   public KingsHand() {
   }
 
-  public KingsHand(EventObserver obs) {
-    super(obs);
+  public KingsHand(EventObserver obs, Event e) {
+    super(obs, e);
   }
 
   @Override
@@ -42,6 +42,5 @@ public class KingsHand extends EventEmitter implements EventObserver {
 
   @Override
   public void timePasses(Weekday day) {
-    // NOP
   }
 }

event-aggregator/src/main/java/com/iluwatar/event/aggregator/LordBaelish.java

@@ -31,8 +31,8 @@ public class LordBaelish extends EventEmitter {
   public LordBaelish() {
   }
 
-  public LordBaelish(EventObserver obs) {
-    super(obs);
+  public LordBaelish(EventObserver obs, Event e) {
+    super(obs, e);
   }
 
   @Override

event-aggregator/src/main/java/com/iluwatar/event/aggregator/LordVarys.java

@@ -23,16 +23,19 @@
 
 package com.iluwatar.event.aggregator;
 
+import lombok.extern.slf4j.Slf4j;
+
 /**
  * LordVarys produces events.
  */
-public class LordVarys extends EventEmitter {
+@Slf4j
+public class LordVarys extends EventEmitter implements EventObserver {
 
   public LordVarys() {
   }
 
-  public LordVarys(EventObserver obs) {
-    super(obs);
+  public LordVarys(EventObserver obs, Event e) {
+    super(obs, e);
   }
 
   @Override
@@ -41,4 +44,10 @@ public class LordVarys extends EventEmitter {
       notifyObservers(Event.TRAITOR_DETECTED);
     }
   }
+
+
+  @Override
+  public void onEvent(Event e) {
+    notifyObservers(e);
+  }
 }

event-aggregator/src/main/java/com/iluwatar/event/aggregator/Scout.java

@@ -31,8 +31,8 @@ public class Scout extends EventEmitter {
   public Scout() {
   }
 
-  public Scout(EventObserver obs) {
-    super(obs);
+  public Scout(EventObserver obs, Event e) {
+    super(obs, e);
   }
 
   @Override
@@ -40,5 +40,8 @@ public class Scout extends EventEmitter {
     if (day == Weekday.TUESDAY) {
       notifyObservers(Event.WARSHIPS_APPROACHING);
     }
+    if (day == Weekday.WEDNESDAY) {
+      notifyObservers(Event.WHITE_WALKERS_SIGHTED);
+    }
   }
 }

event-aggregator/src/test/java/com/iluwatar/event/aggregator/EventEmitterTest.java

@@ -31,6 +31,7 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.verifyZeroInteractions;
 
 import java.util.Objects;
+import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import org.junit.jupiter.api.Test;
@@ -46,7 +47,7 @@ abstract class EventEmitterTest<E extends EventEmitter> {
   /**
    * Factory used to create a new instance of the test object with a default observer
    */
-  private final Function<EventObserver, E> factoryWithDefaultObserver;
+  private final BiFunction<EventObserver, Event, E> factoryWithDefaultObserver;
 
   /**
    * Factory used to create a new instance of the test object without passing a default observer
@@ -67,7 +68,7 @@ abstract class EventEmitterTest<E extends EventEmitter> {
    * Create a new event emitter test, using the given test object factories, special day and event
    */
   EventEmitterTest(final Weekday specialDay, final Event event,
-                   final Function<EventObserver, E> factoryWithDefaultObserver,
+                   final BiFunction<EventObserver, Event, E> factoryWithDefaultObserver,
                    final Supplier<E> factoryWithoutDefaultObserver) {
 
     this.specialDay = specialDay;
@@ -129,8 +130,8 @@ abstract class EventEmitterTest<E extends EventEmitter> {
     final var observer2 = mock(EventObserver.class);
 
     final var emitter = this.factoryWithoutDefaultObserver.get();
-    emitter.registerObserver(observer1);
-    emitter.registerObserver(observer2);
+    emitter.registerObserver(observer1, event);
+    emitter.registerObserver(observer2, event);
 
     testAllDays(specialDay, event, emitter, observer1, observer2);
   }
@@ -146,9 +147,9 @@ abstract class EventEmitterTest<E extends EventEmitter> {
     final var observer1 = mock(EventObserver.class);
     final var observer2 = mock(EventObserver.class);
 
-    final var emitter = this.factoryWithDefaultObserver.apply(defaultObserver);
-    emitter.registerObserver(observer1);
-    emitter.registerObserver(observer2);
+    final var emitter = this.factoryWithDefaultObserver.apply(defaultObserver, event);
+    emitter.registerObserver(observer1, event);
+    emitter.registerObserver(observer2, event);
 
     testAllDays(specialDay, event, emitter, defaultObserver, observer1, observer2);
   }

event-aggregator/src/test/java/com/iluwatar/event/aggregator/KingsHandTest.java

@@ -55,7 +55,11 @@ class KingsHandTest extends EventEmitterTest<KingsHand> {
   @Test
   void testPassThrough() throws Exception {
     final var observer = mock(EventObserver.class);
-    final var kingsHand = new KingsHand(observer);
+    final var kingsHand = new KingsHand();
+    kingsHand.registerObserver(observer, Event.STARK_SIGHTED);
+    kingsHand.registerObserver(observer, Event.WARSHIPS_APPROACHING);
+    kingsHand.registerObserver(observer, Event.TRAITOR_DETECTED);
+    kingsHand.registerObserver(observer, Event.WHITE_WALKERS_SIGHTED);
 
     // The kings hand should not pass any events before he received one
     verifyZeroInteractions(observer);

event-aggregator/src/test/java/com/iluwatar/event/aggregator/ScoutTest.java

@@ -34,7 +34,9 @@ class ScoutTest extends EventEmitterTest<Scout> {
    * Create a new test instance, using the correct object factory
    */
   public ScoutTest() {
-    super(Weekday.TUESDAY, Event.WARSHIPS_APPROACHING, Scout::new, Scout::new);
+
+      super(Weekday.TUESDAY, Event.WARSHIPS_APPROACHING, Scout::new, Scout::new);
+
   }
 
 }

reactor/src/main/java/com/iluwatar/reactor/framework/NioReactor.java

@@ -96,9 +96,11 @@ public class NioReactor {
    * @throws IOException          if any I/O error occurs.
    */
   public void stop() throws InterruptedException, IOException {
-    reactorMain.shutdownNow();
+    reactorMain.shutdown();
     selector.wakeup();
-    reactorMain.awaitTermination(4, TimeUnit.SECONDS);
+    if (!reactorMain.awaitTermination(4, TimeUnit.SECONDS)) {
+      reactorMain.shutdownNow();
+    }
     selector.close();
     LOGGER.info("Reactor stopped");
   }

reactor/src/main/java/com/iluwatar/reactor/framework/ThreadPoolDispatcher.java

@@ -64,6 +64,8 @@ public class ThreadPoolDispatcher implements Dispatcher {
   @Override
   public void stop() throws InterruptedException {
     executorService.shutdown();
-    executorService.awaitTermination(4, TimeUnit.SECONDS);
+    if (executorService.awaitTermination(4, TimeUnit.SECONDS)) {
+      executorService.shutdownNow();
+    }
   }
 }

thread-pool/README.md

@@ -18,11 +18,11 @@ threads and eliminating the latency of creating new threads.
 
 ## Explanation
 
-Real world example
+Real-world example
 
 > We have a large number of relatively short tasks at hand. We need to peel huge amounts of potatoes 
-> and serve mighty amount of coffee cups. Creating a new thread for each task would be a waste so we 
-> establish a thread pool.       
+> and serve a mighty amount of coffee cups. Creating a new thread for each task would be a waste so 
+> we establish a thread pool.       
 
 In plain words
 
@@ -99,7 +99,7 @@ public class PotatoPeelingTask extends Task {
 }
 ```
 
-Next we present a runnable `Worker` class that the thread pool will utilize to handle all the potato 
+Next, we present a runnable `Worker` class that the thread pool will utilize to handle all the potato 
 peeling and coffee making.
 
 ```java

throttling/README.md

@@ -16,10 +16,12 @@ Ensure that a given client is not able to access service resources more than the
 
 ## Explanation
 
-Real world example
+Real-world example
 
-> A large multinational corporation offers API to its customers. The API is rate-limited and each 
-> customer can only make certain amount of calls per second.      
+> A young human and an old dwarf walk into a bar. They start ordering beers from the bartender.
+> The bartender immediately sees that the young human shouldn't consume too many drinks too fast
+> and refuses to serve if enough time has not passed. For the old dwarf, the serving rate can
+> be higher.
 
 In plain words
 
@@ -33,30 +35,25 @@ In plain words
 
 **Programmatic Example**
 
-Tenant class presents the clients of the API. CallsCount tracks the number of API calls per tenant.
+`BarCustomer` class presents the clients of the `Bartender` API. `CallsCount` tracks the number of 
+calls per `BarCustomer`.
 
 ```java
-public class Tenant {
+public class BarCustomer {
 
-  private final String name;
-  private final int allowedCallsPerSecond;
+    @Getter
+    private final String name;
+    @Getter
+    private final int allowedCallsPerSecond;
 
-  public Tenant(String name, int allowedCallsPerSecond, CallsCount callsCount) {
-    if (allowedCallsPerSecond < 0) {
-      throw new InvalidParameterException("Number of calls less than 0 not allowed");
+    public BarCustomer(String name, int allowedCallsPerSecond, CallsCount callsCount) {
+        if (allowedCallsPerSecond < 0) {
+            throw new InvalidParameterException("Number of calls less than 0 not allowed");
+        }
+        this.name = name;
+        this.allowedCallsPerSecond = allowedCallsPerSecond;
+        callsCount.addTenant(name);
     }
-    this.name = name;
-    this.allowedCallsPerSecond = allowedCallsPerSecond;
-    callsCount.addTenant(name);
-  }
-
-  public String getName() {
-    return name;
-  }
-
-  public int getAllowedCallsPerSecond() {
-    return allowedCallsPerSecond;
-  }
 }
 
 @Slf4j
@@ -76,14 +73,14 @@ public final class CallsCount {
   }
 
   public void reset() {
-    LOGGER.debug("Resetting the map.");
     tenantCallsCount.replaceAll((k, v) -> new AtomicLong(0));
+    LOGGER.info("reset counters");
   }
 }
 ```
 
-Next we introduce the service that the tenants are calling. To track the call count we use the 
-throttler timer.
+Next, the service that the tenants are calling is introduced. To track the call count, a throttler 
+timer is used.
 
 ```java
 public interface Throttler {
@@ -111,71 +108,103 @@ public class ThrottleTimerImpl implements Throttler {
     }, 0, throttlePeriod);
   }
 }
+```
 
-class B2BService {
+`Bartender` offers the `orderDrink` service to the `BarCustomer`s. The customers probably don't
+know that the beer serving rate is limited by their appearances.
 
-  private static final Logger LOGGER = LoggerFactory.getLogger(B2BService.class);
-  private final CallsCount callsCount;
+```java
+class Bartender {
 
-  public B2BService(Throttler timer, CallsCount callsCount) {
-    this.callsCount = callsCount;
-    timer.start();
-  }
+    private static final Logger LOGGER = LoggerFactory.getLogger(Bartender.class);
+    private final CallsCount callsCount;
 
-  public int dummyCustomerApi(Tenant tenant) {
-    var tenantName = tenant.getName();
-    var count = callsCount.getCount(tenantName);
-    LOGGER.debug("Counter for {} : {} ", tenant.getName(), count);
-    if (count >= tenant.getAllowedCallsPerSecond()) {
-      LOGGER.error("API access per second limit reached for: {}", tenantName);
-      return -1;
+    public Bartender(Throttler timer, CallsCount callsCount) {
+        this.callsCount = callsCount;
+        timer.start();
     }
-    callsCount.incrementCount(tenantName);
-    return getRandomCustomerId();
-  }
 
-  private int getRandomCustomerId() {
-    return ThreadLocalRandom.current().nextInt(1, 10000);
-  }
+    public int orderDrink(BarCustomer barCustomer) {
+        var tenantName = barCustomer.getName();
+        var count = callsCount.getCount(tenantName);
+        if (count >= barCustomer.getAllowedCallsPerSecond()) {
+            LOGGER.error("I'm sorry {}, you've had enough for today!", tenantName);
+            return -1;
+        }
+        callsCount.incrementCount(tenantName);
+        LOGGER.debug("Serving beer to {} : [{} consumed] ", barCustomer.getName(), count+1);
+        return getRandomCustomerId();
+    }
+
+    private int getRandomCustomerId() {
+        return ThreadLocalRandom.current().nextInt(1, 10000);
+    }
 }
 ```
 
-Now we are ready to see the full example in action. Tenant Adidas is rate-limited to 5 calls per 
-second and Nike to 6.
+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) {
+public static void main(String[] args) {
     var callsCount = new CallsCount();
-    var adidas = new Tenant("Adidas", 5, callsCount);
-    var nike = new Tenant("Nike", 6, callsCount);
+    var human = new BarCustomer("young human", 2, callsCount);
+    var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
 
     var executorService = Executors.newFixedThreadPool(2);
-    executorService.execute(() -> makeServiceCalls(adidas, callsCount));
-    executorService.execute(() -> makeServiceCalls(nike, callsCount));
-    executorService.shutdown();
-    
-    try {
-      executorService.awaitTermination(10, TimeUnit.SECONDS);
-    } catch (InterruptedException e) {
-      LOGGER.error("Executor Service terminated: {}", e.getMessage());
-    }
-  }
 
-  private static void makeServiceCalls(Tenant tenant, CallsCount callsCount) {
-    var timer = new ThrottleTimerImpl(10, callsCount);
-    var service = new B2BService(timer, callsCount);
+    executorService.execute(() -> makeServiceCalls(human, callsCount));
+    executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
+
+    executorService.shutdown();
+    try {
+        executorService.awaitTermination(10, TimeUnit.SECONDS);
+    } catch (InterruptedException e) {
+        LOGGER.error("Executor service terminated: {}", e.getMessage());
+    }
+}
+
+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, 20).forEach(i -> {
-      service.dummyCustomerApi(tenant);
-      try {
-        Thread.sleep(1);
-      } catch (InterruptedException e) {
-        LOGGER.error("Thread interrupted: {}", e.getMessage());
-      }
+    IntStream.range(0, 50).forEach(i -> {
+        service.orderDrink(barCustomer);
+        try {
+            Thread.sleep(100);
+        } catch (InterruptedException e) {
+            LOGGER.error("Thread interrupted: {}", e.getMessage());
+        }
     });
-  }
+}
 ```
 
+An excerpt from the example's console output:
+
+```
+18:46:36.218 [Timer-0] INFO com.iluwatar.throttling.CallsCount - reset counters
+18:46:36.218 [Timer-1] INFO com.iluwatar.throttling.CallsCount - reset counters
+18:46:36.242 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [1 consumed] 
+18:46:36.242 [pool-1-thread-1] DEBUG com.iluwatar.throttling.Bartender - Serving beer to young human : [1 consumed] 
+18:46:36.342 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [2 consumed] 
+18:46:36.342 [pool-1-thread-1] DEBUG com.iluwatar.throttling.Bartender - Serving beer to young human : [2 consumed] 
+18:46:36.443 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.443 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [3 consumed] 
+18:46:36.544 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.544 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [4 consumed] 
+18:46:36.645 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.645 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.745 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.745 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.846 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.846 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.947 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.947 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:37.048 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:37.048 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:37.148 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+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
 
@@ -185,7 +214,7 @@ second and Nike to 6.
 
 The Throttling pattern should be used:
 
-* When a service access needs to be restricted to not have high impacts on the performance of the service.
+* When service access needs to be restricted not to have high impact on the performance of the service.
 * When multiple clients are consuming the same service resources and restriction has to be made according to the usage per client.
 
 ## Credits

throttling/src/main/java/com/iluwatar/throttling/App.java

@@ -34,11 +34,11 @@ import lombok.extern.slf4j.Slf4j;
  * complete service by users or a particular tenant. This can allow systems to continue to function
  * and meet service level agreements, even when an increase in demand places load on resources.
  * <p>
- * In this example we have ({@link App}) as the initiating point of the service. This is a time
+ * In this example there is a {@link Bartender} serving beer to {@link BarCustomer}s. This is a time
  * based throttling, i.e. only a certain number of calls are allowed per second.
  * </p>
- * ({@link Tenant}) is the Tenant POJO class with which many tenants can be created ({@link
- * B2BService}) is the service which is consumed by the tenants and is throttled.
+ * ({@link BarCustomer}) is the service tenant class having a name and the number of calls allowed.
+ * ({@link Bartender}) is the service which is consumed by the tenants and is throttled.
  */
 @Slf4j
 public class App {
@@ -50,33 +50,35 @@ public class App {
    */
   public static void main(String[] args) {
     var callsCount = new CallsCount();
-    var adidas = new Tenant("Adidas", 5, callsCount);
-    var nike = new Tenant("Nike", 6, callsCount);
+    var human = new BarCustomer("young human", 2, callsCount);
+    var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
 
     var executorService = Executors.newFixedThreadPool(2);
 
-    executorService.execute(() -> makeServiceCalls(adidas, callsCount));
-    executorService.execute(() -> makeServiceCalls(nike, callsCount));
+    executorService.execute(() -> makeServiceCalls(human, callsCount));
+    executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
 
     executorService.shutdown();
     try {
-      executorService.awaitTermination(10, TimeUnit.SECONDS);
+      if (!executorService.awaitTermination(10, TimeUnit.SECONDS)) {
+        executorService.shutdownNow();
+      }
     } catch (InterruptedException e) {
-      LOGGER.error("Executor Service terminated: {}", e.getMessage());
+      executorService.shutdownNow();
     }
   }
 
   /**
-   * Make calls to the B2BService dummy API.
+   * Make calls to the bartender.
    */
-  private static void makeServiceCalls(Tenant tenant, CallsCount callsCount) {
-    var timer = new ThrottleTimerImpl(10, callsCount);
-    var service = new B2BService(timer, 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, 20).forEach(i -> {
-      service.dummyCustomerApi(tenant);
+    IntStream.range(0, 50).forEach(i -> {
+      service.orderDrink(barCustomer);
       try {
-        Thread.sleep(1);
+        Thread.sleep(100);
       } catch (InterruptedException e) {
         LOGGER.error("Thread interrupted: {}", e.getMessage());
       }

throttling/src/main/java/com/iluwatar/throttling/BarCustomer.java

@@ -25,22 +25,26 @@ package com.iluwatar.throttling;
 
 import java.security.InvalidParameterException;
 
-/**
- * A Pojo class to create a basic Tenant with the allowed calls per second.
- */
-public class Tenant {
+import lombok.Getter;
 
+/**
+ * BarCustomer is a tenant with a name and a number of allowed calls per second.
+ */
+public class BarCustomer {
+
+  @Getter
   private final String name;
+  @Getter
   private final int allowedCallsPerSecond;
 
   /**
    * Constructor.
    *
-   * @param name                  Name of the tenant
-   * @param allowedCallsPerSecond The number of calls allowed for a particular tenant.
+   * @param name Name of the BarCustomer
+   * @param allowedCallsPerSecond The number of calls allowed for this particular tenant.
    * @throws InvalidParameterException If number of calls is less than 0, throws exception.
    */
-  public Tenant(String name, int allowedCallsPerSecond, CallsCount callsCount) {
+  public BarCustomer(String name, int allowedCallsPerSecond, CallsCount callsCount) {
     if (allowedCallsPerSecond < 0) {
       throw new InvalidParameterException("Number of calls less than 0 not allowed");
     }
@@ -48,12 +52,4 @@ public class Tenant {
     this.allowedCallsPerSecond = allowedCallsPerSecond;
     callsCount.addTenant(name);
   }
-
-  public String getName() {
-    return name;
-  }
-
-  public int getAllowedCallsPerSecond() {
-    return allowedCallsPerSecond;
-  }
 }

throttling/src/main/java/com/iluwatar/throttling/Bartender.java

@@ -29,33 +29,32 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * A service which accepts a tenant and throttles the resource based on the time given to the
- * tenant.
+ * Bartender is a service which accepts a BarCustomer (tenant) and throttles
+ * the resource based on the time given to the tenant.
  */
-class B2BService {
+class Bartender {
 
-  private static final Logger LOGGER = LoggerFactory.getLogger(B2BService.class);
+  private static final Logger LOGGER = LoggerFactory.getLogger(Bartender.class);
   private final CallsCount callsCount;
 
-  public B2BService(Throttler timer, CallsCount callsCount) {
+  public Bartender(Throttler timer, CallsCount callsCount) {
     this.callsCount = callsCount;
     timer.start();
   }
 
   /**
-   * Calls dummy customer api.
-   *
+   * Orders a drink from the bartender.
    * @return customer id which is randomly generated
    */
-  public int dummyCustomerApi(Tenant tenant) {
-    var tenantName = tenant.getName();
+  public int orderDrink(BarCustomer barCustomer) {
+    var tenantName = barCustomer.getName();
     var count = callsCount.getCount(tenantName);
-    LOGGER.debug("Counter for {} : {} ", tenant.getName(), count);
-    if (count >= tenant.getAllowedCallsPerSecond()) {
-      LOGGER.error("API access per second limit reached for: {}", tenantName);
+    if (count >= barCustomer.getAllowedCallsPerSecond()) {
+      LOGGER.error("I'm sorry {}, you've had enough for today!", tenantName);
       return -1;
     }
     callsCount.incrementCount(tenantName);
+    LOGGER.debug("Serving beer to {} : [{} consumed] ", barCustomer.getName(), count + 1);
     return getRandomCustomerId();
   }
 

throttling/src/main/java/com/iluwatar/throttling/CallsCount.java

@@ -69,7 +69,7 @@ public final class CallsCount {
    * Resets the count of all the tenants in the map.
    */
   public void reset() {
-    LOGGER.debug("Resetting the map.");
     tenantCallsCount.replaceAll((k, v) -> new AtomicLong(0));
+    LOGGER.info("reset counters");
   }
 }

throttling/src/test/java/com/iluwatar/throttling/BarCustomerTest.java

@@ -23,20 +23,21 @@
 
 package com.iluwatar.throttling;
 
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import org.junit.jupiter.api.Test;
 
 import java.security.InvalidParameterException;
-import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * TenantTest to test the creation of Tenant with valid parameters.
  */
-public class TenantTest {
+public class BarCustomerTest {
 
   @Test
   void constructorTest() {
     assertThrows(InvalidParameterException.class, () -> {
-      new Tenant("FailTenant", -1, new CallsCount());
+      new BarCustomer("sirBrave", -1, new CallsCount());
     });
   }
 }

throttling/src/test/java/com/iluwatar/throttling/BartenderTest.java

@@ -32,19 +32,18 @@ import org.junit.jupiter.api.Test;
 /**
  * B2BServiceTest class to test the B2BService
  */
-public class B2BServiceTest {
+public class BartenderTest {
 
   private final CallsCount callsCount = new CallsCount();
 
   @Test
   void dummyCustomerApiTest() {
-    var tenant = new Tenant("testTenant", 2, callsCount);
+    var tenant = new BarCustomer("pirate", 2, callsCount);
     // In order to assure that throttling limits will not be reset, we use an empty throttling implementation
-    var timer = (Throttler) () -> {
-    };
-    var service = new B2BService(timer, callsCount);
+    var timer = (Throttler) () -> {};
+    var service = new Bartender(timer, callsCount);
 
-    IntStream.range(0, 5).mapToObj(i -> tenant).forEach(service::dummyCustomerApi);
+    IntStream.range(0, 5).mapToObj(i -> tenant).forEach(service::orderDrink);
     var counter = callsCount.getCount(tenant.getName());
     assertEquals(2, counter, "Counter limit must be reached");
   }