fix: Synchronization fixes in temperature service

src/main/java/eu/ztsh/lfr/core/impl/TemperaturesServiceImpl.java

@@ -11,35 +11,32 @@ import org.springframework.context.event.EventListener;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
 
 @Service
 public class TemperaturesServiceImpl implements TemperaturesService {
 
     private static final Logger log = LoggerFactory.getLogger(TemperaturesServiceImpl.class);
-    private Averages averages;
+    private final AtomicReference<Averages> averages = new AtomicReference<>();
 
     @Nonnull
     @Override
-    public List<Average> getTemperaturesFor(String city) {
+    public synchronized List<Average> getTemperaturesFor(String city) {
-        synchronized (this) {
+        while (averages.get() == null) {
-            while (averages == null) {
+            try {
-                try {
+                wait();
-                    wait();
+            } catch (InterruptedException e) {
-                } catch (InterruptedException e) {
+                log.error("Thread was interrupted", e);
-                    log.error("Thread was interrupted", e);
+                Thread.currentThread().interrupt();
-                    Thread.currentThread().interrupt();
-                }
             }
-            return averages.get(city);
         }
+        return averages.get().get(city);
     }
 
     @EventListener(FileProcessedEvent.class)
-    public void updateTemperatures(FileProcessedEvent event) {
+    public synchronized void updateTemperatures(FileProcessedEvent event) {
-        synchronized (this) {
+        averages.set(event.averages());
-            averages = event.averages();
+        notifyAll();
-            notifyAll();
-        }
     }
 
 }