Index: src/main/java/org/apache/jackrabbit/core/security/user/MembershipCache.java
===================================================================
--- src/main/java/org/apache/jackrabbit/core/security/user/MembershipCache.java	(revision 1518513)
+++ src/main/java/org/apache/jackrabbit/core/security/user/MembershipCache.java	(working copy)
@@ -203,6 +203,10 @@
         return cache.size();
     }
 
+    synchronized void clear() {
+        cache.clear();
+    }
+
     /**
      * Collects the declared memberships for the specified identifier of an
      * authorizable using the specified session.
Index: src/test/java/org/apache/jackrabbit/core/security/user/MembershipCacheTest.java
===================================================================
--- src/test/java/org/apache/jackrabbit/core/security/user/MembershipCacheTest.java	(revision 0)
+++ src/test/java/org/apache/jackrabbit/core/security/user/MembershipCacheTest.java	(revision 0)
@@ -0,0 +1,235 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.jackrabbit.core.security.user;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+import javax.jcr.Node;
+import javax.jcr.RepositoryException;
+import javax.jcr.SimpleCredentials;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.jackrabbit.api.JackrabbitSession;
+import org.apache.jackrabbit.api.security.user.Group;
+import org.apache.jackrabbit.api.security.user.User;
+import org.apache.jackrabbit.api.security.user.UserManager;
+import org.apache.jackrabbit.core.RepositoryImpl;
+import org.apache.jackrabbit.core.config.RepositoryConfig;
+import org.apache.jackrabbit.test.JUnitTest;
+
+/**
+ * <code>MembershipCacheTest</code>...
+ */
+public class MembershipCacheTest extends JUnitTest {
+
+    private static final String TEST_USER_PREFIX = "MembershipCacheTestUser-";
+    private static final String REPO_HOME = new File("target",
+            MembershipCacheTest.class.getSimpleName()).getPath();
+    private static final int NUM_USERS = 100;
+    private static final int NUM_GROUPS = 8;
+    private static final int NUM_READERS = 8;
+    private RepositoryImpl repo;
+    private JackrabbitSession session;
+    private UserManager userMgr;
+    private MembershipCache cache;
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        FileUtils.deleteDirectory(new File(REPO_HOME));
+        RepositoryConfig config = RepositoryConfig.create(
+                getClass().getResourceAsStream("repository.xml"), REPO_HOME);
+        repo = RepositoryImpl.create(config);
+        session = createSession();
+        userMgr = session.getUserManager();
+        cache = ((UserManagerImpl) userMgr).getMembershipCache();
+        boolean autoSave = userMgr.isAutoSave();
+        userMgr.autoSave(false);
+        // create test users and groups
+        List<User> users = new ArrayList<User>();
+        for (int i = 0; i < NUM_USERS; i++) {
+            users.add(userMgr.createUser(TEST_USER_PREFIX + i, "secret"));
+        }
+        for (int i = 0; i < NUM_GROUPS; i++) {
+            Group g = userMgr.createGroup("MembershipCacheTestGroup-" + i);
+            for (User u : users) {
+                g.addMember(u);
+            }
+        }
+        session.save();
+        userMgr.autoSave(autoSave);
+        logger.info("Initial cache size: " + cache.getSize());
+    }
+
+    @Override
+    protected void tearDown() throws Exception {
+        boolean autoSave = userMgr.isAutoSave();
+        userMgr.autoSave(false);
+        for (int i = 0; i < NUM_USERS; i++) {
+            userMgr.getAuthorizable(TEST_USER_PREFIX + i).remove();
+        }
+        for (int i = 0; i < NUM_GROUPS; i++) {
+            userMgr.getAuthorizable("MembershipCacheTestGroup-" + i).remove();
+        }
+        session.save();
+        userMgr.autoSave(autoSave);
+        userMgr = null;
+        cache = null;
+        session.logout();
+        repo.shutdown();
+        repo = null;
+        FileUtils.deleteDirectory(new File(REPO_HOME));
+        super.tearDown();
+    }
+
+    public void testConcurrency() throws Exception {
+        Stats stats = new Stats();
+        List<Exception> exceptions = Collections.synchronizedList(new ArrayList<Exception>());
+        List<Reader> readers = new ArrayList<Reader>();
+        for (int i = 0; i < NUM_READERS; i++) {
+            Reader r = new Reader(createSession(), stats, exceptions);
+            r.addUser(TEST_USER_PREFIX + 0);
+            readers.add(r);
+        }
+        Node test = session.getRootNode().addNode("test", "nt:unstructured");
+        session.save();
+        for (Reader r : readers) {
+            r.start();
+        }
+        for (int i = 1; i < NUM_USERS; i++) {
+            test.addNode("node-" + i);
+            session.save();
+            for (Reader r : readers) {
+                r.addUser(TEST_USER_PREFIX + i);
+            }
+        }
+        for (Reader r : readers) {
+            r.join();
+        }
+        test.remove();
+        session.save();
+        System.out.println(stats);
+        for (Exception e : exceptions) {
+            throw e;
+        }
+    }
+
+    public void testRun75() throws Exception {
+        for (int i = 0; i < 75; i++) {
+            testConcurrency();
+            cache.clear();
+        }
+    }
+
+    private JackrabbitSession createSession() throws RepositoryException {
+        return (JackrabbitSession) repo.login(
+                new SimpleCredentials("admin", "admin".toCharArray()));
+    }
+
+    private static final class Reader extends Thread {
+
+        private final JackrabbitSession session;
+        private final UserManager userMgr;
+        private final Stats stats;
+        private final List<Object> knownUsers = new ArrayList<Object>();
+        private final Random random = new Random();
+        private final List<Exception> exceptions;
+
+        public Reader(JackrabbitSession s,
+                      Stats stats,
+                      List<Exception> exceptions)
+                throws RepositoryException {
+            this.session = s;
+            this.userMgr = s.getUserManager();
+            this.stats = stats;
+            this.exceptions = exceptions;
+        }
+
+        void addUser(String user) {
+            synchronized (knownUsers) {
+                knownUsers.add(user);
+            }
+        }
+
+        public void run() {
+            try {
+                while (knownUsers.size() < NUM_USERS) {
+                    Object idOrUser;
+                    int idx;
+                    synchronized (knownUsers) {
+                        idx = random.nextInt(knownUsers.size());
+                        idOrUser = knownUsers.get(idx);
+                    }
+                    User user;
+                    if (idOrUser instanceof String) {
+                        user = (User) userMgr.getAuthorizable((String) idOrUser);
+                        synchronized (knownUsers) {
+                            knownUsers.set(idx, user);
+                        }
+                    } else {
+                        user = (User) idOrUser;
+                    }
+                    long time = System.nanoTime();
+                    user.memberOf();
+                    stats.logTime(System.nanoTime() - time);
+                }
+            } catch (RepositoryException e) {
+                exceptions.add(e);
+            } finally {
+                session.logout();
+            }
+        }
+    }
+
+    private static final class Stats {
+
+        private AtomicLong[] buckets = new AtomicLong[20];
+
+        public Stats() {
+            for (int i = 0; i < buckets.length; i++) {
+                buckets[i] = new AtomicLong();
+            }
+        }
+
+        void logTime(long nanos) {
+            if (nanos == 0) {
+                buckets[0].incrementAndGet();
+            } else {
+                buckets[(int) Math.log10(nanos)].incrementAndGet();
+            }
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder sb = new StringBuilder();
+            String separator = "";
+            for (AtomicLong bucket : buckets) {
+                sb.append(separator);
+                sb.append(bucket.get());
+                separator = ",";
+            }
+            return sb.toString();
+        }
+    }
+
+
+}

Property changes on: src\test\java\org\apache\jackrabbit\core\security\user\MembershipCacheTest.java
___________________________________________________________________
Added: svn:keywords
   + Author Date Id Revision Rev URL
Added: svn:eol-style
   + native