OF-588: Add synchronization for cache swap during cluster startup/shutdown

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/trunk@13382 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/util/cache/CacheFactory.java

@@ -381,7 +381,7 @@ public class CacheFactory {
      *
      * @param name the name of the cache to destroy.
      */
-    public static void destroyCache(String name) {
+    public static synchronized void destroyCache(String name) {
         Cache cache = caches.remove(name);
         if (cache != null) {
             if (localOnly.contains(name)) {
@@ -411,9 +411,13 @@ public class CacheFactory {
         if (localOnly.contains(cache.getName())) {
         	return localCacheFactoryStrategy.getLock(key, cache);
         } else {
+        	// synchronized here because the backing cache
+        	// will be swapped cluster startup/shutdown (OF-588)
+        	synchronized(cache) {
         		return cacheFactoryStrategy.getLock(key, cache);
         	}
         }
+    }
 
     @SuppressWarnings("unchecked")
     private static <T extends Cache> T wrapCache(T cache, String name) {
@@ -686,11 +690,13 @@ public class CacheFactory {
         for (Cache cache : getAllCaches()) {
             // skip local-only caches
             if (localOnly.contains(cache.getName())) continue;
+            synchronized (cache) {
 	            cache.clear();
 	            CacheWrapper cacheWrapper = ((CacheWrapper) cache);
 	            Cache clusteredCache = cacheFactoryStrategy.createCache(cacheWrapper.getName());
 	            cacheWrapper.setWrappedCache(clusteredCache);
             }
+        }
         clusteringStarting = false;
         clusteringStarted = true;
     }
@@ -708,11 +714,13 @@ public class CacheFactory {
             for (Cache cache : getAllCaches()) {
                 // skip local-only caches
                 if (localOnly.contains(cache.getName())) continue;
+                synchronized (cache) {
 	                cache.clear();
 	                CacheWrapper cacheWrapper = ((CacheWrapper) cache);
 	                Cache standaloneCache = cacheFactoryStrategy.createCache(cacheWrapper.getName());
 	                cacheWrapper.setWrappedCache(standaloneCache);
                 }
+        	}
         } catch (Exception e) {
             log.error("Error reverting caches to local caches", e);
         }