improve cache invalidation on group events

scm-webapp/src/main/java/sonia/scm/security/AuthorizationCollector.java

@@ -72,6 +72,8 @@ import sonia.scm.util.Util;
 import java.util.List;
 import java.util.Set;
 import sonia.scm.Filter;
+import sonia.scm.group.Group;
+import sonia.scm.group.GroupModificationEvent;
 import sonia.scm.repository.RepositoryModificationEvent;
 import sonia.scm.user.UserModificationEvent;
 
@@ -183,7 +185,8 @@ public class AuthorizationCollector
     return user.isAdmin() != beforeModification.isAdmin() || user.isActive() != beforeModification.isActive();
   }
 
-  private void invalidateUserCache(final String username){
+  private void invalidateUserCache(final String username)
+  {
     logger.debug("invalidate cache of user {}, because of a event which could change the permissions", username);
     cache.removeAll(new Filter<CacheKey>()
     {
@@ -279,24 +282,48 @@ public class AuthorizationCollector
   }
 
   /**
-   * Method description
+   * Invalidates the whole cache, if a group has changed. The cache get cleared for one of the following reasons:
+   * <ul>
+   * <li>New group created</li>
+   * <li>Group was removed</li>
+   * <li>Group members was modified</li>
+   * </ul>
    *
-   *
-   * @param event
+   * @param event group event
    */
   @Subscribe
   public void onEvent(GroupEvent event)
   {
     if (event.getEventType().isPost())
     {
-      if (logger.isDebugEnabled())
+      Group group = event.getItem();
+      if (event instanceof GroupModificationEvent)
       {
-        logger.debug("clear cache, because group {} has changed",
-          event.getItem().getId());
-      }
-
+        Group beforeModification = ((GroupModificationEvent) event).getItemBeforeModification();
+        if (shouldCacheBeCleared(group, beforeModification))
+        {
+          logger.debug("clear cache, because group {} has changed", group.getId());
           cache.clear();
         }
+        else
+        {
+          logger.debug(
+            "cache of group {} is not invalidated, because non relevant fields have changed",
+            group.getId()
+          );
+        }
+      }
+      else
+      {
+        logger.debug("clear cache, because group {} has changed", group.getId());
+        cache.clear();
+      }
+    }
+  }
+
+  private boolean shouldCacheBeCleared(Group group, Group beforeModification)
+  {
+    return !group.getMembers().equals(beforeModification.getMembers());
   }
 
   /**
@@ -414,8 +441,8 @@ public class AuthorizationCollector
   private void collectRepositoryPermissions(Builder<Permission> builder,
     Repository repository, User user, GroupNames groups)
   {
-    List<sonia.scm.repository.Permission> repositoryPermissions =
-      repository.getPermissions();
+    List<sonia.scm.repository.Permission> repositoryPermissions
+      = repository.getPermissions();
 
     if (Util.isNotEmpty(repositoryPermissions))
     {
@@ -589,7 +616,6 @@ public class AuthorizationCollector
     private final String username;
   }
 
-
   //~--- fields ---------------------------------------------------------------
 
   /** Field description */

scm-webapp/src/test/java/sonia/scm/security/AuthorizationCollectorTest.java

@@ -59,6 +59,7 @@ import sonia.scm.cache.Cache;
 import sonia.scm.cache.CacheManager;
 import sonia.scm.group.Group;
 import sonia.scm.group.GroupEvent;
+import sonia.scm.group.GroupModificationEvent;
 import sonia.scm.group.GroupNames;
 import sonia.scm.repository.PermissionType;
 import sonia.scm.repository.Repository;
@@ -163,6 +164,25 @@ public class AuthorizationCollectorTest {
     verify(cache).clear();
   }
   
+  /**
+   * Tests {@link AuthorizationCollector#onEvent(sonia.scm.group.GroupEvent)} with modified groups.
+   */
+  @Test
+  public void testOnGroupModificationEvent()
+  {
+    Group group = new Group("xml", "base");
+    Group modifiedGroup = new Group("xml", "base");
+    collector.onEvent(new GroupModificationEvent(modifiedGroup, group, HandlerEvent.BEFORE_MODIFY));
+    verify(cache, never()).clear();
+    
+    collector.onEvent(new GroupModificationEvent(modifiedGroup, group, HandlerEvent.MODIFY));
+    verify(cache, never()).clear();
+    
+    modifiedGroup.add("test");
+    collector.onEvent(new GroupModificationEvent(modifiedGroup, group, HandlerEvent.MODIFY));
+    verify(cache).clear();
+  }
+  
   /**
    * Tests {@link AuthorizationCollector#onEvent(sonia.scm.repository.RepositoryEvent)}.
    */