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docs: update throttling

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Ilkka Seppälä
2024-05-27 14:09:08 +03:00
parent 8372d925f5
commit a6458c469d
1 changed files with 35 additions and 30 deletions
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throttling/README.md
+35 -30
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@@ -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)