publish LocalSessionDestroyedEvent on session removal from local cache

src/main/java/org/springframework/session/sticky/StickySessionCache.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.session.sticky;
 
-import static java.util.Comparator.comparing;
-
 import java.lang.ref.WeakReference;
 import java.time.Duration;
 import java.time.Instant;
@@ -27,7 +25,10 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.lang.Nullable;
+import org.springframework.session.Session;
+import org.springframework.session.events.SessionDestroyedEvent;
 import org.springframework.session.sticky.StickySessionRepository.CacheEntry;
 import org.springframework.util.Assert;
 
@@ -46,10 +47,17 @@ public class StickySessionCache {
 
   protected Duration cleanupAfter = Duration.ofMinutes(DEFAULT_CLEANUP_AFTER_MINUTES);
 
+  private ApplicationEventPublisher eventPublisher = event -> {
+  };
+
   public StickySessionCache(int cacheConcurrency) {
     this.sessions = new ConcurrentHashMap<>(16, 0.75F, cacheConcurrency);
   }
 
+  public void setApplicationEventPublisher(ApplicationEventPublisher eventPublisher) {
+    this.eventPublisher = eventPublisher;
+  }
+
   /**
    * Cached session entries that have not been accessed for {@linkplain #cleanupAfter the configured period} will
    * be removed from the cache (but not the remote store) when {@link #cleanupOutdatedCacheEntries()} is called.
@@ -76,9 +84,11 @@ public void put(CacheEntry entry) {
 
   @Nullable
   public void remove(String id) {
-    sessions.remove(id);
+    final CacheEntry cacheEntry = sessions.remove(id);
     // We don't remove from cleanup cache here, because that would require a separate mapping of session ids.
     // The weak reference will be cleared, and the cleanup entry will simply be skipped when it's due.
+
+    eventPublisher.publishEvent(new LocalSessionDestroyedEvent(this, cacheEntry.createView()));
   }
 
   /**
@@ -142,12 +152,17 @@ void cleanup() {
         if (session.getLastAccessedTime().isBefore(maxLastAccessed)) {
           if (logger.isDebugEnabled())
             logger.debug("Cached session " + session.getId() + " is scheduled for cleanup, removing from cache.");
-          sessions.remove(session.getId());
+          StickySessionCache.this.remove(session.getId());
         } else {
           schedule(session);
         }
       }
     }
   }
 
+  public static class LocalSessionDestroyedEvent extends SessionDestroyedEvent {
+    private LocalSessionDestroyedEvent(Object source, Session session) {
+      super(source, session);
+    }
+  }
 }

src/main/java/org/springframework/session/sticky/StickySessionRepository.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.session.sticky;
 
-import static java.util.Comparator.comparing;
-
 import java.time.Duration;
 import java.time.Instant;
 import java.util.HashMap;
@@ -339,7 +337,7 @@ private synchronized void saveDelegate() {
       delegateAwaitsSave = false;
     }
 
-    private synchronized StickySession createView() {
+    synchronized StickySession createView() {
       if (logger.isTraceEnabled())
         logger.trace("Creating new session view for " + getId());
       return new StickySession(this, new MapSession(cached));

src/main/java/org/springframework/session/sticky/config/annotation/web/http/StickyHttpSessionConfiguration.java

@@ -20,8 +20,6 @@
 
 import java.time.Duration;
 import java.util.Map;
-import java.util.concurrent.Executor;
-import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
 import org.springframework.beans.factory.annotation.Autowired;
@@ -140,6 +138,7 @@ public DelegateSaveStrategy stickySessionDelegateSaveStrategy() {
   public StickySessionCache stickySessionCache() {
     StickySessionCache cache = new StickySessionCache(this.sessionConcurrency);
     cache.setCleanupAfter(this.cleanupAfter);
+    cache.setApplicationEventPublisher(this.eventPublisher);
     return cache;
   }