diff --git a/syncbase/src/main/java/io/v/syncbase/AccessList.java b/syncbase/src/main/java/io/v/syncbase/AccessList.java
index 075ad1c..2494529 100644
--- a/syncbase/src/main/java/io/v/syncbase/AccessList.java
+++ b/syncbase/src/main/java/io/v/syncbase/AccessList.java
@@ -48,10 +48,19 @@
         this.users = new HashMap<>();
     }
 
+    /**
+     * Gets the user's access level.
+     */
     public AccessLevel getAccessLevelForUser(User user) {
         return users.get(user.getAlias());
     }
 
+    /**
+     * Changes the user's access level and returns their previous access level.
+     *
+     * @param user The user whose access level is changing.
+     * @param newLevel The user's new access level.
+     */
     public AccessLevel setAccessLevel(User user, AccessLevel newLevel) {
         if (newLevel == null) {
             return removeAccessLevel(user);
@@ -61,11 +70,31 @@
         return oldLevel;
     }
 
+    /**
+     * Removes access from the given user.
+     */
     public AccessLevel removeAccessLevel(User user) {
         return users.remove(user);
     }
 
     /**
+     * Obtains the users that match the given access level.
+     * Filters out the cloud, which always has READ_WRITE_ADMIN access.
+     */
+    public java.util.Collection<User> getByAccessLevel(AccessLevel level) {
+        Set<User> matchingUsers = new HashSet<>();
+        for (Map.Entry<String, AccessLevel> entry : users.entrySet()) {
+            String alias = entry.getKey();
+            boolean isCloud = Syncbase.sOpts.mCloudAdmin != null &&
+                    alias.equals(Syncbase.getAliasFromBlessingPattern(Syncbase.sOpts.mCloudAdmin));
+            if (!isCloud && entry.getValue().equals(level)) {
+                matchingUsers.add(new User(alias));
+            }
+        }
+        return matchingUsers;
+    }
+
+    /**
      * TODO(alexfandrianto): Vary implementation if this constructor needs to be called with non-
      * collection permissions. The current simplification allows us to know that read/write/admin
      * are available for parsing.
diff --git a/syncbase/src/main/java/io/v/syncbase/Database.java b/syncbase/src/main/java/io/v/syncbase/Database.java
index 47b1034..83134b0 100644
--- a/syncbase/src/main/java/io/v/syncbase/Database.java
+++ b/syncbase/src/main/java/io/v/syncbase/Database.java
@@ -14,6 +14,7 @@
 import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import io.v.syncbase.core.CollectionRowPattern;
 import io.v.syncbase.core.SyncgroupMemberInfo;
@@ -504,6 +505,8 @@
             throw new UnsupportedOperationException("Specifying resumeMarker is not yet supported");
         }
 
+        final AtomicBoolean canceled = new AtomicBoolean(false);
+
         mCoreDatabase.watch(null, ImmutableList.of(opts.getCollectionRowPattern()),
                 new io.v.syncbase.core.Database.WatchPatternsCallbacks() {
                     private boolean mGotFirstBatch = false;
@@ -511,6 +514,10 @@
 
                     @Override
                     public void onChange(io.v.syncbase.core.WatchChange coreWatchChange) {
+                        if (canceled.get()) {
+                            return;
+                        }
+
                         boolean isRoot = coreWatchChange.entityType ==
                                 io.v.syncbase.core.WatchChange.EntityType.ROOT;
                         boolean isUserdataInternalRow =
@@ -564,7 +571,8 @@
             mWatchChangeHandlers.put(h, new Runnable() {
                 @Override
                 public void run() {
-                    throw new UnsupportedOperationException("Not implemented");
+                    // TODO(alexfandrianto): Implement properly. AtomicBoolean is only a patch.
+                    canceled.set(true);
                 }
             });
         }
diff --git a/syncbase/src/test/java/io/v/syncbase/DatabaseTest.java b/syncbase/src/test/java/io/v/syncbase/DatabaseTest.java
index b9b1490..667c7a8 100644
--- a/syncbase/src/test/java/io/v/syncbase/DatabaseTest.java
+++ b/syncbase/src/test/java/io/v/syncbase/DatabaseTest.java
@@ -53,66 +53,66 @@
         // Wildcard and prefix tests.
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                         .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "%");
-        assertEquals(opts.row, "%");
+        assertEquals("%", opts.blessing);
+        assertEquals("%", opts.name);
+        assertEquals("%", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                         .setCollectionId(new Id("a", "b"))
                         .build();
-        assertEquals(opts.blessing, "a");
-        assertEquals(opts.name, "b");
-        assertEquals(opts.row, "%");
+        assertEquals("a", opts.blessing);
+        assertEquals("b", opts.name);
+        assertEquals("%", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setCollectionNamePrefix("c")
                 .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "c%");
-        assertEquals(opts.row, "%");
+        assertEquals("%", opts.blessing);
+        assertEquals("c%", opts.name);
+        assertEquals("%", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setRowKey("d")
                 .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "%");
-        assertEquals(opts.row, "d");
+        assertEquals("%", opts.blessing);
+        assertEquals("%", opts.name);
+        assertEquals("d", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setRowKeyPrefix("e")
                 .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "%");
-        assertEquals(opts.row, "e%");
+        assertEquals("%", opts.blessing);
+        assertEquals("%", opts.name);
+        assertEquals("e%", opts.row);
 
         // Escaping tests. %, _ and \ are special characters.
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setCollectionId(new Id("%", "_"))
                 .build();
-        assertEquals(opts.blessing, "\\%");
-        assertEquals(opts.name, "\\_");
-        assertEquals(opts.row, "%");
+        assertEquals("\\%", opts.blessing);
+        assertEquals("\\_", opts.name);
+        assertEquals("%", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setCollectionNamePrefix("\\")
                 .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "\\\\%");
-        assertEquals(opts.row, "%");
+        assertEquals("%", opts.blessing);
+        assertEquals("\\\\%", opts.name);
+        assertEquals("%", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setRowKey("%%")
                 .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "%");
-        assertEquals(opts.row, "\\%\\%");
+        assertEquals("%", opts.blessing);
+        assertEquals("%", opts.name);
+        assertEquals("\\%\\%", opts.row);
 
         opts = new Database.AddWatchChangeHandlerOptions.Builder()
                 .setRowKeyPrefix("_\\_")
                 .build();
-        assertEquals(opts.blessing, "%");
-        assertEquals(opts.name, "%");
-        assertEquals(opts.row, "\\_\\\\\\_%");
+        assertEquals("%", opts.blessing);
+        assertEquals("%", opts.name);
+        assertEquals("\\_\\\\\\_%", opts.row);
     }
 
 }
diff --git a/syncbase/src/test/java/io/v/syncbase/SyncbaseTest.java b/syncbase/src/test/java/io/v/syncbase/SyncbaseTest.java
index 66a63a6..d2b7679 100644
--- a/syncbase/src/test/java/io/v/syncbase/SyncbaseTest.java
+++ b/syncbase/src/test/java/io/v/syncbase/SyncbaseTest.java
@@ -124,18 +124,18 @@
         Collection cx = db.createCollection();
         assertNotNull(cx);
         assertFalse(cx.exists("foo"));
-        assertEquals(cx.get("foo", String.class), null);
+        assertEquals(null, cx.get("foo", String.class));
         cx.put("foo", "bar");
         assertTrue(cx.exists("foo"));
-        assertEquals(cx.get("foo", String.class), "bar");
+        assertEquals("bar", cx.get("foo", String.class));
         cx.put("foo", "baz");
         assertTrue(cx.exists("foo"));
-        assertEquals(cx.get("foo", String.class), "baz");
+        assertEquals("baz", cx.get("foo", String.class));
         cx.delete("foo");
         assertFalse(cx.exists("foo"));
-        assertEquals(cx.get("foo", String.class), null);
+        assertEquals(null, cx.get("foo", String.class));
         cx.put("foo", 5);
-        assertEquals(cx.get("foo", Integer.class), Integer.valueOf(5));
+        assertEquals(Integer.valueOf(5), cx.get("foo", Integer.class));
 
         // TODO(razvanm): Figure out a way to get the POJOs to work.
 //        // This time, with a POJO.
@@ -395,7 +395,7 @@
 
         TestOperation op = new TestOperation();
         db.runInBatch(op);
-        assertEquals(db.getCollection(op.id).get("foo", Integer.class), Integer.valueOf(10));
+        assertEquals(Integer.valueOf(10), db.getCollection(op.id).get("foo", Integer.class));
     }
 
     @Test
@@ -413,6 +413,10 @@
         assertNull(acl0.getAccessLevelForUser(alice));
         assertNull(acl0.getAccessLevelForUser(bob));
         assertNull(acl0.getAccessLevelForUser(carol));
+        assertEquals(0, acl0.getByAccessLevel(AccessList.AccessLevel.READ).size());
+        assertEquals(0, acl0.getByAccessLevel(AccessList.AccessLevel.READ_WRITE).size());
+        // Note: This is 1 because the creator of the collection starts with RWA access.
+        assertEquals(1, acl0.getByAccessLevel(AccessList.AccessLevel.READ_WRITE_ADMIN).size());
 
         // Alice can read now.
         sg.inviteUser(new User("alice"), AccessList.AccessLevel.READ);
@@ -420,6 +424,9 @@
         assertEquals(acl1.getAccessLevelForUser(alice), AccessList.AccessLevel.READ);
         assertNull(acl1.getAccessLevelForUser(bob));
         assertNull(acl1.getAccessLevelForUser(carol));
+        assertEquals(1, acl1.getByAccessLevel(AccessList.AccessLevel.READ).size());
+        assertEquals(0, acl1.getByAccessLevel(AccessList.AccessLevel.READ_WRITE).size());
+        assertEquals(1, acl1.getByAccessLevel(AccessList.AccessLevel.READ_WRITE_ADMIN).size());
 
         // Bob can both read and write now.
         sg.inviteUser(new User("bob"), AccessList.AccessLevel.READ_WRITE);
@@ -427,6 +434,9 @@
         assertEquals(acl2.getAccessLevelForUser(alice), AccessList.AccessLevel.READ);
         assertEquals(acl2.getAccessLevelForUser(bob), AccessList.AccessLevel.READ_WRITE);
         assertNull(acl2.getAccessLevelForUser(carol));
+        assertEquals(1, acl2.getByAccessLevel(AccessList.AccessLevel.READ).size());
+        assertEquals(1, acl2.getByAccessLevel(AccessList.AccessLevel.READ_WRITE).size());
+        assertEquals(1, acl2.getByAccessLevel(AccessList.AccessLevel.READ_WRITE_ADMIN).size());
 
         // Alice and Carol get full access now. (Tests overwrite and multiple invites.)
         sg.inviteUsers(ImmutableList.of(new User("alice"), new User("carol")),
@@ -435,6 +445,9 @@
         assertEquals(acl3.getAccessLevelForUser(alice), AccessList.AccessLevel.READ_WRITE_ADMIN);
         assertEquals(acl3.getAccessLevelForUser(bob), AccessList.AccessLevel.READ_WRITE);
         assertEquals(acl3.getAccessLevelForUser(carol), AccessList.AccessLevel.READ_WRITE_ADMIN);
+        assertEquals(0, acl3.getByAccessLevel(AccessList.AccessLevel.READ).size());
+        assertEquals(1, acl3.getByAccessLevel(AccessList.AccessLevel.READ_WRITE).size());
+        assertEquals(3, acl3.getByAccessLevel(AccessList.AccessLevel.READ_WRITE_ADMIN).size());
     }
 
     @Test