Index: oak-core/src/test/java/org/apache/jackrabbit/oak/kernel/SlingDiff.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- oak-core/src/test/java/org/apache/jackrabbit/oak/kernel/SlingDiff.java	(revision )
+++ oak-core/src/test/java/org/apache/jackrabbit/oak/kernel/SlingDiff.java	(revision )
@@ -0,0 +1,159 @@
+/*
+ * 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.oak.kernel;
+
+import static org.apache.jackrabbit.oak.commons.PathUtils.concat;
+
+import java.util.Map;
+import java.util.Set;
+
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import org.apache.jackrabbit.oak.api.PropertyState;
+import org.apache.jackrabbit.oak.plugins.memory.EmptyNodeState;
+import org.apache.jackrabbit.oak.spi.commit.Observer;
+import org.apache.jackrabbit.oak.spi.state.NodeState;
+import org.apache.jackrabbit.oak.spi.state.NodeStateDiff;
+
+public class SlingDiff implements NodeStateDiff, Observer {
+    private final String path;
+    private final Map<String, PropertyState> properties = Maps.newHashMap();
+    private final Set<PropertyState> added = Sets.newHashSet();
+    private final Set<PropertyState> changed = Sets.newHashSet();
+    private final Set<PropertyState> deleted = Sets.newHashSet();
+
+    public SlingDiff() {
+        this("/");
+    }
+
+    public SlingDiff(String path) {
+        this.path = path;
+    }
+
+    @Override
+    public void contentChanged(NodeState before, NodeState after) {
+        after.compareAgainstBaseState(before, this);
+        addIfNotNull(after, "jcr:primaryType");
+        addIfNotNull(after, "sling:resourceType");
+        addIfNotNull(after, "sling:resourceSuperType");
+
+        if (before == EmptyNodeState.EMPTY_NODE) {
+            nodeAdded(path, properties, added);
+        } else if (after == EmptyNodeState.EMPTY_NODE) {
+            nodeDeleted(path, properties, deleted);
+        } else if (!added.isEmpty() || !changed.isEmpty() || !deleted.isEmpty()) {
+            nodeChanged(path, properties, added, changed, deleted);
+        }
+    }
+
+    private void addIfNotNull(NodeState nodeState, String name) {
+        PropertyState property = nodeState.getProperty(name);
+        if (property != null) {
+            properties.put(name, property);
+        }
+    }
+
+    protected void nodeAdded(String path, Map<String, PropertyState> typeProperties,
+            Set<PropertyState> added) {
+        System.out.println("Added node at " + path);
+        printProperties(typeProperties.values());
+        if (!added.isEmpty()) {
+            System.out.println("Added properties");
+            printProperties(added);
+        }
+        System.out.println();
+    }
+
+    protected void nodeDeleted(String path, Map<String, PropertyState> typeProperties,
+            Set<PropertyState> deleted) {
+        System.out.println("Deleted node at " + path);
+        printProperties(typeProperties.values());
+        if (!deleted.isEmpty()) {
+            System.out.println("Deleted properties");
+            printProperties(deleted);
+        }
+        System.out.println();
+    }
+
+    protected void nodeChanged(String path, Map<String, PropertyState> typeProperties,
+            Set<PropertyState> added, Set<PropertyState> changed, Set<PropertyState> deleted) {
+        System.out.println("Changed node at " + path);
+        printProperties(typeProperties.values());
+        if (!added.isEmpty()) {
+            System.out.println("Added properties");
+            printProperties(added);
+        }
+        if (!deleted.isEmpty()) {
+            System.out.println("Deleted properties");
+            printProperties(deleted);
+        }
+        if (!changed.isEmpty()) {
+            System.out.println("Changed properties");
+            printProperties(changed);
+        }
+        System.out.println();
+    }
+
+    private static void printProperties(Iterable<PropertyState> properties) {
+        for (PropertyState property : properties) {
+            System.out.println(property);
+        }
+    }
+
+    @Override
+    public boolean propertyAdded(PropertyState after) {
+        added.add(after);
+        return true;
+    }
+
+    @Override
+    public boolean propertyChanged(PropertyState before, PropertyState after) {
+        changed.add(after);
+        return true;
+    }
+
+    @Override
+    public boolean propertyDeleted(PropertyState before) {
+        deleted.add(before);
+        return true;
+    }
+
+    @Override
+    public boolean childNodeAdded(String name, NodeState after) {
+        new SlingDiff(concat(path, name))
+                .contentChanged(EmptyNodeState.EMPTY_NODE, after);
+        return true;
+    }
+
+    @Override
+    public boolean childNodeChanged(String name, NodeState before, NodeState after) {
+        new SlingDiff(concat(path, name))
+                .contentChanged(before, after);
+        return true;
+    }
+
+    @Override
+    public boolean childNodeDeleted(String name, NodeState before) {
+        new SlingDiff(concat(path, name))
+                .contentChanged(before, EmptyNodeState.EMPTY_NODE);
+        return true;
+    }
+
+}
Index: oak-core/src/test/java/org/apache/jackrabbit/oak/kernel/NodeStoreTest.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- oak-core/src/test/java/org/apache/jackrabbit/oak/kernel/NodeStoreTest.java	(revision 181aaca44320997d57ab3115033440f3fb897d46)
+++ oak-core/src/test/java/org/apache/jackrabbit/oak/kernel/NodeStoreTest.java	(revision )
@@ -173,6 +173,22 @@
     }
 
     @Test
+    public void slingCommitHook() throws CommitFailedException {
+        // this test only works with a KernelNodeStore
+        assumeTrue(store instanceof KernelNodeStore);
+        ((KernelNodeStore) store).setObserver(new SlingDiff());
+
+        NodeBuilder root= store.getRoot().builder();
+        NodeBuilder test = root.getChildNode("test");
+        NodeBuilder newNode = test.child("newNode").setProperty("n", 42);
+        test.getChildNode("x").remove();
+        test.removeProperty("a");
+
+        store.merge(root, EmptyHook.INSTANCE, null);
+        NodeState newRoot = store.getRoot(); // triggers the observer
+    }
+
+    @Test
     public void beforeCommitHook() throws CommitFailedException {
         NodeState root = store.getRoot();
         NodeBuilder rootBuilder = root.builder();