HONEYCOMB-8: Move data layer from impl module into submodules

Change-Id: Ic75793f65cfcad7cc2c96e7a09093e0e1802e4e5
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>

7 files changed, 909 insertions, 0 deletions

diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/DataTreeUtils.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/DataTreeUtils.java
new file mode 100644
index 000000000..83ed0f263
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/DataTreeUtils.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import com.google.common.base.Preconditions;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import org.opendaylight.mdsal.binding.dom.codec.api.BindingNormalizedNodeSerializer;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
+import org.opendaylight.yangtools.yang.data.api.schema.DataContainerNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Utility class for various operations on DataTree.
+ */
+final class DataTreeUtils {
+    private static final Logger LOG = LoggerFactory.getLogger(DataTreeUtils.class);
+
+    private DataTreeUtils() {
+        throw new UnsupportedOperationException("Can't instantiate util class");
+    }
+
+    /**
+     * Translates children of supplied YANG ContainerNode into Binding data.
+     *
+     * @param parent     ContainerNode representing data
+     * @param serializer service for serialization between Java Binding Data representation and NormalizedNode
+     *                   representation.
+     * @return NormalizedNode representation of parent's node children
+     */
+    static Map<InstanceIdentifier<?>, DataObject> childrenFromNormalized(@Nonnull final DataContainerNode parent,
+                                                                         @Nonnull final BindingNormalizedNodeSerializer serializer) {
+
+        Preconditions.checkNotNull(parent, "parent node should not be null");
+        Preconditions.checkNotNull(serializer, "serializer should not be null");
+
+        final Map<InstanceIdentifier<?>, DataObject> map = new HashMap<>();
+
+        final Collection<DataContainerChild<? extends YangInstanceIdentifier.PathArgument, ?>> children =
+                parent.getValue();
+
+        for (final DataContainerChild<? extends YangInstanceIdentifier.PathArgument, ?> child : children) {
+            final YangInstanceIdentifier.PathArgument pathArgument = child.getIdentifier();
+            final YangInstanceIdentifier identifier = YangInstanceIdentifier.create(pathArgument);
+            LOG.debug("VppConfigDataProxy.extractDataObject() child={}, pathArgument={}, identifier={}", child,
+                    pathArgument, identifier);
+
+            final Map.Entry<InstanceIdentifier<?>, DataObject> entry = serializer.fromNormalizedNode(identifier, child);
+            if (entry != null) {
+                map.put(entry.getKey(), entry.getValue());
+            }
+        }
+
+        return map;
+    }
+}
diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/ReadWriteTransaction.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/ReadWriteTransaction.java
new file mode 100644
index 000000000..88b46437e
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/ReadWriteTransaction.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.ListenableFuture;
+import javax.annotation.Nonnull;
+import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadOnlyTransaction;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadTransaction;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadWriteTransaction;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
+import org.opendaylight.yangtools.yang.common.RpcResult;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+
+/**
+ * Composite DOM transaction that delegates reads to a {@link DOMDataReadTransaction} delegate and writes to a {@link
+ * DOMDataWriteTransaction} delegate.
+ */
+final class ReadWriteTransaction implements DOMDataReadWriteTransaction {
+
+    private final DOMDataReadOnlyTransaction delegateReadTx;
+    private final DOMDataWriteTransaction delegateWriteTx;
+
+    ReadWriteTransaction(@Nonnull final DOMDataReadOnlyTransaction delegateReadTx,
+                         @Nonnull final DOMDataWriteTransaction delegateWriteTx) {
+        this.delegateReadTx = Preconditions.checkNotNull(delegateReadTx, "delegateReadTx should not be null");
+        this.delegateWriteTx = Preconditions.checkNotNull(delegateWriteTx, "delegateWriteTx should not be null");
+    }
+
+    @Override
+    public boolean cancel() {
+        delegateReadTx.close();
+        return delegateWriteTx.cancel();
+    }
+
+    @Override
+    public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path,
+                    final NormalizedNode<?, ?> data) {
+        delegateWriteTx.put(store, path, data);
+    }
+
+    @Override
+    public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path,
+                      final NormalizedNode<?, ?> data) {
+        delegateWriteTx.merge(store, path, data);
+    }
+
+    @Override
+    public void delete(final LogicalDatastoreType store, final YangInstanceIdentifier path) {
+        delegateWriteTx.delete(store, path);
+    }
+
+    @Override
+    public CheckedFuture<Void, TransactionCommitFailedException> submit() {
+        return delegateWriteTx.submit();
+    }
+
+    @Override
+    public ListenableFuture<RpcResult<TransactionStatus>> commit() {
+        return delegateWriteTx.commit();
+    }
+
+    @Override
+    public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(final LogicalDatastoreType store,
+                                                                                   final YangInstanceIdentifier path) {
+        return delegateReadTx.read(store, path);
+    }
+
+    @Override
+    public CheckedFuture<Boolean, ReadFailedException> exists(final LogicalDatastoreType store,
+                                                              final YangInstanceIdentifier path) {
+        return delegateReadTx.exists(store, path);
+    }
+
+    @Override
+    public Object getIdentifier() {
+        return this;
+    }
+}
+
diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppConfigDataTree.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppConfigDataTree.java
new file mode 100644
index 000000000..6e01306b0
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppConfigDataTree.java
@@ -0,0 +1,172 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static io.fd.honeycomb.v3po.data.impl.DataTreeUtils.childrenFromNormalized;
+
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import io.fd.honeycomb.v3po.data.ReadableVppDataTree;
+import io.fd.honeycomb.v3po.data.VppDataTree;
+import io.fd.honeycomb.v3po.data.VppDataTreeSnapshot;
+import io.fd.honeycomb.v3po.translate.TranslationException;
+import io.fd.honeycomb.v3po.translate.util.write.TransactionWriteContext;
+import io.fd.honeycomb.v3po.translate.write.WriteContext;
+import io.fd.honeycomb.v3po.translate.write.WriterRegistry;
+import java.util.Collections;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadOnlyTransaction;
+import org.opendaylight.mdsal.binding.dom.codec.api.BindingNormalizedNodeSerializer;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.DataContainerNode;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateNode;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * VppDataTree implementation for configuration data.
+ */
+public final class VppConfigDataTree implements VppDataTree {
+
+    private static final Logger LOG = LoggerFactory.getLogger(VppConfigDataTree.class);
+
+    private final BindingNormalizedNodeSerializer serializer;
+    private final DataTree dataTree;
+    private final WriterRegistry writer;
+    public static final ReadableVppDataTree EMPTY_OPERATIONAL = new ReadableVppDataTree() {
+        @Override
+        public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(
+                @Nonnull final YangInstanceIdentifier path) {
+            return Futures.immediateCheckedFuture(Optional.<NormalizedNode<?, ?>>absent());
+        }
+    };
+
+    /**
+     * Creates configuration data tree instance.
+     *
+     * @param serializer service for serialization between Java Binding Data representation and NormalizedNode
+     *                   representation.
+     * @param dataTree   data tree for configuration data representation
+     * @param vppWriter  service for translation between Java Binding Data and Vpp.
+     */
+    public VppConfigDataTree(@Nonnull final BindingNormalizedNodeSerializer serializer,
+                             @Nonnull final DataTree dataTree, @Nonnull final WriterRegistry vppWriter) {
+        this.serializer = checkNotNull(serializer, "serializer should not be null");
+        this.dataTree = checkNotNull(dataTree, "dataTree should not be null");
+        this.writer = checkNotNull(vppWriter, "vppWriter should not be null");
+    }
+
+    @Override
+    public VppDataTreeSnapshot takeSnapshot() {
+        return new ConfigSnapshot(dataTree.takeSnapshot());
+    }
+
+    @Override
+    public void commit(final DataTreeModification modification)
+            throws DataValidationFailedException, TranslationException {
+        dataTree.validate(modification);
+
+        final DataTreeCandidate candidate = dataTree.prepare(modification);
+
+        final DataTreeCandidateNode rootNode = candidate.getRootNode();
+        final YangInstanceIdentifier rootPath = candidate.getRootPath();
+        final Optional<NormalizedNode<?, ?>> normalizedDataBefore = rootNode.getDataBefore();
+        final Optional<NormalizedNode<?, ?>> normalizedDataAfter = rootNode.getDataAfter();
+        LOG.debug("VppConfigDataTree.commit() rootPath={}, rootNode={}, dataBefore={}, dataAfter={}",
+                rootPath, rootNode, normalizedDataBefore, normalizedDataAfter);
+
+        final Map<InstanceIdentifier<?>, DataObject> nodesBefore = extractNetconfData(normalizedDataBefore);
+        LOG.debug("VppConfigDataTree.commit() extracted nodesBefore={}", nodesBefore.keySet());
+
+        final Map<InstanceIdentifier<?>, DataObject> nodesAfter = extractNetconfData(normalizedDataAfter);
+        LOG.debug("VppConfigDataTree.commit() extracted nodesAfter={}", nodesAfter.keySet());
+
+
+        final DOMDataReadOnlyTransaction beforeTx = new VppReadOnlyTransaction(EMPTY_OPERATIONAL, takeSnapshot());
+        final ConfigSnapshot modificationSnapshot = new ConfigSnapshot(modification);
+        final DOMDataReadOnlyTransaction afterTx = new VppReadOnlyTransaction(EMPTY_OPERATIONAL, modificationSnapshot);
+        try(final WriteContext ctx = new TransactionWriteContext(serializer, beforeTx, afterTx)) {
+            writer.update(nodesBefore, nodesAfter, ctx);
+        } catch (io.fd.honeycomb.v3po.translate.write.WriterRegistry.BulkUpdateException e) {
+            LOG.warn("Failed to apply all changes", e);
+            LOG.info("Trying to revert successful changes for current transaction");
+
+            try {
+                e.revertChanges();
+                LOG.info("Changes successfully reverted");
+            } catch (io.fd.honeycomb.v3po.translate.write.WriterRegistry.Reverter.RevertFailedException revertFailedException) {
+                // fail with failed revert
+                LOG.error("Failed to revert successful changes", revertFailedException);
+                throw revertFailedException;
+            }
+
+            throw e; // fail with success revert
+        } catch (TranslationException e) {
+            LOG.error("Error while processing data change (before={}, after={})", nodesBefore, nodesAfter, e);
+            throw e;
+        }
+
+        dataTree.commit(candidate);
+    }
+
+    private Map<InstanceIdentifier<?>, DataObject> extractNetconfData(
+            final Optional<NormalizedNode<?, ?>> parentOptional) {
+        if (parentOptional.isPresent()) {
+            final DataContainerNode parent = (DataContainerNode) parentOptional.get();
+            return childrenFromNormalized(parent, serializer);
+        }
+        return Collections.emptyMap();
+    }
+
+    private final static class ConfigSnapshot implements VppDataTreeSnapshot {
+        private final DataTreeSnapshot snapshot;
+
+        ConfigSnapshot(@Nonnull final DataTreeSnapshot snapshot) {
+            this.snapshot = snapshot;
+        }
+
+        @Override
+        public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(
+                @Nonnull final YangInstanceIdentifier path) {
+            final Optional<NormalizedNode<?, ?>> node = snapshot.readNode(path);
+            if (LOG.isTraceEnabled() && node.isPresent()) {
+                LOG.trace("ConfigSnapshot.read: {}", node.get());
+            }
+            return Futures.immediateCheckedFuture(node);
+        }
+
+        @Override
+        public DataTreeModification newModification() {
+            return snapshot.newModification();
+        }
+    }
+}
+
+
+
diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppDataBroker.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppDataBroker.java
new file mode 100644
index 000000000..5c5248cea
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppDataBroker.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import com.google.common.base.Preconditions;
+import io.fd.honeycomb.v3po.data.ReadableVppDataTree;
+import io.fd.honeycomb.v3po.data.VppDataTree;
+import io.fd.honeycomb.v3po.data.VppDataTreeSnapshot;
+import java.util.Collections;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.TransactionChainListener;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataBroker;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataBrokerExtension;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataChangeListener;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadOnlyTransaction;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadWriteTransaction;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
+import org.opendaylight.controller.md.sal.dom.api.DOMTransactionChain;
+import org.opendaylight.yangtools.concepts.ListenerRegistration;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+
+/**
+ * Data Broker which provides data transaction functionality for VPP using {@link NormalizedNode} data format.
+ */
+public class VppDataBroker implements DOMDataBroker {
+
+    private final ReadableVppDataTree operationalData;
+    private final VppDataTree configDataTree;
+
+    /**
+     * Creates VppDataBroker instance.
+     *
+     * @param operationalData VPP operational data
+     * @param configDataTree  VPP configuration data
+     */
+    public VppDataBroker(@Nonnull final ReadableVppDataTree operationalData,
+                         @Nonnull final VppDataTree configDataTree) {
+        this.operationalData = Preconditions.checkNotNull(operationalData, "operationalData should not be null");
+        this.configDataTree = Preconditions.checkNotNull(configDataTree, "configDataProxy should not be null");
+    }
+
+    @Override
+    public DOMDataReadOnlyTransaction newReadOnlyTransaction() {
+        return new VppReadOnlyTransaction(operationalData, configDataTree.takeSnapshot());
+    }
+
+    @Override
+    public DOMDataReadWriteTransaction newReadWriteTransaction() {
+        // todo use the same snapshot
+        final VppDataTreeSnapshot configSnapshot = configDataTree.takeSnapshot();
+        final DOMDataReadOnlyTransaction readOnlyTx = new VppReadOnlyTransaction(operationalData, configSnapshot);
+        final DOMDataWriteTransaction writeOnlyTx = new VppWriteTransaction(configDataTree, configSnapshot);
+        return new ReadWriteTransaction(readOnlyTx, writeOnlyTx);
+    }
+
+    @Override
+    public DOMDataWriteTransaction newWriteOnlyTransaction() {
+        return new VppWriteTransaction(configDataTree);
+    }
+
+    @Override
+    public ListenerRegistration<DOMDataChangeListener> registerDataChangeListener(final LogicalDatastoreType store,
+                                                                                  final YangInstanceIdentifier path,
+                                                                                  final DOMDataChangeListener listener,
+                                                                                  final DataChangeScope triggeringScope) {
+        throw new UnsupportedOperationException("Not supported");
+    }
+
+    @Override
+    public DOMTransactionChain createTransactionChain(final TransactionChainListener listener) {
+        throw new UnsupportedOperationException("Not supported");
+    }
+
+    @Nonnull
+    @Override
+    public Map<Class<? extends DOMDataBrokerExtension>, DOMDataBrokerExtension> getSupportedExtensions() {
+        return Collections.emptyMap();
+    }
+}
+
+
diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppOperationalDataTree.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppOperationalDataTree.java
new file mode 100644
index 000000000..fc13606e6
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppOperationalDataTree.java
@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.collect.Iterables.getOnlyElement;
+
+import com.google.common.base.Function;
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.Multimap;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import io.fd.honeycomb.v3po.data.ReadableVppDataTree;
+import io.fd.honeycomb.v3po.translate.Context;
+import io.fd.honeycomb.v3po.translate.read.ReadContext;
+import io.fd.honeycomb.v3po.translate.read.ReadFailedException;
+import io.fd.honeycomb.v3po.translate.read.ReaderRegistry;
+import java.util.Collection;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import org.opendaylight.mdsal.binding.dom.codec.api.BindingNormalizedNodeSerializer;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode;
+import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
+import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
+import org.opendaylight.yangtools.yang.data.api.schema.MapNode;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.UnkeyedListEntryNode;
+import org.opendaylight.yangtools.yang.data.api.schema.UnkeyedListNode;
+import org.opendaylight.yangtools.yang.data.impl.schema.Builders;
+import org.opendaylight.yangtools.yang.data.impl.schema.builder.api.CollectionNodeBuilder;
+import org.opendaylight.yangtools.yang.data.impl.schema.builder.api.DataContainerNodeAttrBuilder;
+import org.opendaylight.yangtools.yang.model.api.DataSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.ListSchemaNode;
+import org.opendaylight.yangtools.yang.model.api.SchemaContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * ReadableVppDataTree implementation for operational data.
+ */
+public final class VppOperationalDataTree implements ReadableVppDataTree {
+    private static final Logger LOG = LoggerFactory.getLogger(VppOperationalDataTree.class);
+
+    private final BindingNormalizedNodeSerializer serializer;
+    private final ReaderRegistry readerRegistry;
+    private final SchemaContext globalContext;
+
+    /**
+     * Creates operational data tree instance.
+     *
+     * @param serializer     service for serialization between Java Binding Data representation and NormalizedNode
+     *                       representation.
+     * @param globalContext  service for obtaining top level context data from all yang modules.
+     * @param readerRegistry service responsible for translation between DataObjects and VPP APIs.
+     */
+    public VppOperationalDataTree(@Nonnull BindingNormalizedNodeSerializer serializer,
+                                  @Nonnull final SchemaContext globalContext, @Nonnull ReaderRegistry readerRegistry) {
+        this.globalContext = checkNotNull(globalContext, "serializer should not be null");
+        this.serializer = checkNotNull(serializer, "serializer should not be null");
+        this.readerRegistry = checkNotNull(readerRegistry, "reader should not be null");
+    }
+
+    @Override
+    public CheckedFuture<Optional<NormalizedNode<?, ?>>,
+            org.opendaylight.controller.md.sal.common.api.data.ReadFailedException> read(
+            @Nonnull final YangInstanceIdentifier yangInstanceIdentifier) {
+
+        try(ReadContext ctx = new ReadContextImpl()) {
+            if (checkNotNull(yangInstanceIdentifier).equals(YangInstanceIdentifier.EMPTY)) {
+                return Futures.immediateCheckedFuture(readRoot(ctx));
+            } else {
+                return Futures.immediateCheckedFuture(readNode(yangInstanceIdentifier, ctx));
+            }
+        } catch (ReadFailedException e) {
+            return Futures.immediateFailedCheckedFuture(
+                    new org.opendaylight.controller.md.sal.common.api.data.ReadFailedException(
+                            "Failed to read VPP data", e));
+        }
+    }
+
+    private Optional<NormalizedNode<?, ?>> readNode(final YangInstanceIdentifier yangInstanceIdentifier,
+                                                    final ReadContext ctx)
+            throws ReadFailedException {
+        LOG.debug("VppOperationalDataTree.readNode(), yangInstanceIdentifier={}", yangInstanceIdentifier);
+        final InstanceIdentifier<?> path = serializer.fromYangInstanceIdentifier(yangInstanceIdentifier);
+        checkNotNull(path, "Invalid instance identifier %s. Cannot create BA equivalent.", yangInstanceIdentifier);
+        LOG.debug("VppOperationalDataTree.readNode(), path={}", path);
+
+        final Optional<? extends DataObject> dataObject;
+
+        dataObject = readerRegistry.read(path, ctx);
+        if (dataObject.isPresent()) {
+            final NormalizedNode<?, ?> value = toNormalizedNodeFunction(path).apply(dataObject.get());
+            return Optional.<NormalizedNode<?, ?>>fromNullable(value);
+        } else {
+            return Optional.absent();
+        }
+    }
+
+    private Optional<NormalizedNode<?, ?>> readRoot(final ReadContext ctx) throws ReadFailedException {
+        LOG.debug("VppOperationalDataTree.readRoot()");
+
+        final DataContainerNodeAttrBuilder<YangInstanceIdentifier.NodeIdentifier, ContainerNode> dataNodeBuilder =
+                Builders.containerBuilder()
+                        .withNodeIdentifier(new YangInstanceIdentifier.NodeIdentifier(SchemaContext.NAME));
+
+        final Multimap<InstanceIdentifier<? extends DataObject>, ? extends DataObject> dataObjects =
+                readerRegistry.readAll(ctx);
+
+        for (final InstanceIdentifier<? extends DataObject> instanceIdentifier : dataObjects.keySet()) {
+            final YangInstanceIdentifier rootElementId = serializer.toYangInstanceIdentifier(instanceIdentifier);
+            final NormalizedNode<?, ?> node =
+                    wrapDataObjects(rootElementId, instanceIdentifier, dataObjects.get(instanceIdentifier));
+            dataNodeBuilder.withChild((DataContainerChild<?, ?>) node);
+        }
+
+        return Optional.<NormalizedNode<?, ?>>of(dataNodeBuilder.build());
+    }
+
+    private NormalizedNode<?, ?> wrapDataObjects(final YangInstanceIdentifier yangInstanceIdentifier,
+                                                 final InstanceIdentifier<? extends DataObject> instanceIdentifier,
+                                                 final Collection<? extends DataObject> dataObjects) {
+        final Collection<NormalizedNode<?, ?>> normalizedRootElements = Collections2
+                .transform(dataObjects, toNormalizedNodeFunction(instanceIdentifier));
+
+        final DataSchemaNode schemaNode =
+                globalContext.getDataChildByName(yangInstanceIdentifier.getLastPathArgument().getNodeType());
+        if (schemaNode instanceof ListSchemaNode) {
+            // In case of a list, wrap all the values in a Mixin parent node
+            final ListSchemaNode listSchema = (ListSchemaNode) schemaNode;
+            return wrapListIntoMixinNode(normalizedRootElements, listSchema);
+        } else {
+            Preconditions.checkState(dataObjects.size() == 1, "Singleton list was expected");
+            return getOnlyElement(normalizedRootElements);
+        }
+    }
+
+    private static DataContainerChild<?, ?> wrapListIntoMixinNode(
+            final Collection<NormalizedNode<?, ?>> normalizedRootElements, final ListSchemaNode listSchema) {
+        if (listSchema.getKeyDefinition().isEmpty()) {
+            final CollectionNodeBuilder<UnkeyedListEntryNode, UnkeyedListNode> listBuilder =
+                    Builders.unkeyedListBuilder();
+            for (NormalizedNode<?, ?> normalizedRootElement : normalizedRootElements) {
+                listBuilder.withChild((UnkeyedListEntryNode) normalizedRootElement);
+            }
+            return listBuilder.build();
+        } else {
+            final CollectionNodeBuilder<MapEntryNode, ? extends MapNode> listBuilder =
+                    listSchema.isUserOrdered()
+                            ? Builders.orderedMapBuilder()
+                            : Builders.mapBuilder();
+
+            for (NormalizedNode<?, ?> normalizedRootElement : normalizedRootElements) {
+                listBuilder.withChild((MapEntryNode) normalizedRootElement);
+            }
+            return listBuilder.build();
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private Function<DataObject, NormalizedNode<?, ?>> toNormalizedNodeFunction(final InstanceIdentifier path) {
+        return new Function<DataObject, NormalizedNode<?, ?>>() {
+            @Override
+            public NormalizedNode<?, ?> apply(@Nullable final DataObject dataObject) {
+                LOG.trace("VppOperationalDataTree.toNormalizedNode(), path={}, dataObject={}", path, dataObject);
+                final Map.Entry<YangInstanceIdentifier, NormalizedNode<?, ?>> entry =
+                        serializer.toNormalizedNode(path, dataObject);
+
+                LOG.trace("VppOperationalDataTree.toNormalizedNode(), normalizedNodeEntry={}", entry);
+                return entry.getValue();
+            }
+        };
+    }
+
+    private static final class ReadContextImpl implements ReadContext {
+        public final Context ctx = new Context();
+
+        @Nonnull
+        @Override
+        public Context getContext() {
+            return ctx;
+        }
+
+        @Override
+        public void close() {
+            // Make sure to clear the storage in case some customizer stored it  to prevent memory leaks
+            ctx.close();
+        }
+    }
+}
diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppReadOnlyTransaction.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppReadOnlyTransaction.java
new file mode 100644
index 000000000..db01591b9
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppReadOnlyTransaction.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import com.google.common.base.Function;
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import io.fd.honeycomb.v3po.data.ReadableVppDataTree;
+import io.fd.honeycomb.v3po.data.VppDataTreeSnapshot;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataReadOnlyTransaction;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+final class VppReadOnlyTransaction implements DOMDataReadOnlyTransaction {
+
+    private static final Logger LOG = LoggerFactory.getLogger(VppReadOnlyTransaction.class);
+    private volatile ReadableVppDataTree operationalData;
+    private volatile VppDataTreeSnapshot configSnapshot;
+
+    VppReadOnlyTransaction(@Nonnull final ReadableVppDataTree operationalData,
+                           @Nonnull final VppDataTreeSnapshot configSnapshot) {
+        this.operationalData = Preconditions.checkNotNull(operationalData, "operationalData should not be null");
+        this.configSnapshot = Preconditions.checkNotNull(configSnapshot, "config should not be null");
+    }
+
+    @Override
+    public void close() {
+        configSnapshot = null;
+        operationalData = null;
+    }
+
+    @Override
+    public CheckedFuture<Optional<NormalizedNode<?, ?>>, ReadFailedException> read(
+            final LogicalDatastoreType store,
+            final YangInstanceIdentifier path) {
+        LOG.debug("VppReadOnlyTransaction.read(), store={}, path={}", store, path);
+
+        Preconditions.checkState(configSnapshot != null, "Transaction was closed");
+
+        if (store == LogicalDatastoreType.OPERATIONAL) {
+            return operationalData.read(path);
+        } else {
+            return configSnapshot.read(path);
+        }
+    }
+
+    @Override
+    public CheckedFuture<Boolean, ReadFailedException> exists(final LogicalDatastoreType store,
+                                                              final YangInstanceIdentifier path) {
+        LOG.debug("VppReadOnlyTransaction.exists() store={}, path={}", store, path);
+
+        ListenableFuture<Boolean> listenableFuture = Futures.transform(read(store, path), IS_NODE_PRESENT);
+
+        return Futures.makeChecked(listenableFuture, ANY_EX_TO_READ_FAILED_EXCEPTION_MAPPER);
+    }
+
+    @Nonnull
+    @Override
+    public Object getIdentifier() {
+        return this;
+    }
+
+
+    private static final Function<? super Optional<NormalizedNode<?, ?>>, ? extends Boolean> IS_NODE_PRESENT =
+            new Function<Optional<NormalizedNode<?, ?>>, Boolean>() {
+                @Nullable
+                @Override
+                public Boolean apply(@Nullable final Optional<NormalizedNode<?, ?>> input) {
+                    return input == null
+                            ? Boolean.FALSE
+                            : input.isPresent();
+                }
+            };
+
+    private static final Function<? super Exception, ReadFailedException> ANY_EX_TO_READ_FAILED_EXCEPTION_MAPPER =
+            new Function<Exception, ReadFailedException>() {
+                @Override
+                public ReadFailedException apply(@Nullable final Exception e) {
+                    return new ReadFailedException("Exists failed", e);
+                }
+            };
+}
\ No newline at end of file
diff --git a/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppWriteTransaction.java b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppWriteTransaction.java
new file mode 100644
index 000000000..c9766eb21
--- /dev/null
+++ b/v3po/data-impl/src/main/java/io/fd/honeycomb/v3po/data/impl/VppWriteTransaction.java
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed 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 io.fd.honeycomb.v3po.data.impl;
+
+import static org.opendaylight.controller.md.sal.common.api.TransactionStatus.CANCELED;
+import static org.opendaylight.controller.md.sal.common.api.TransactionStatus.COMMITED;
+import static org.opendaylight.controller.md.sal.common.api.TransactionStatus.FAILED;
+import static org.opendaylight.controller.md.sal.common.api.TransactionStatus.NEW;
+import static org.opendaylight.controller.md.sal.common.api.TransactionStatus.SUBMITED;
+
+import com.google.common.base.Preconditions;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import io.fd.honeycomb.v3po.data.VppDataTree;
+import io.fd.honeycomb.v3po.data.VppDataTreeSnapshot;
+import io.fd.honeycomb.v3po.translate.TranslationException;
+import javax.annotation.Nonnull;
+import javax.annotation.concurrent.NotThreadSafe;
+import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
+import org.opendaylight.yangtools.yang.common.RpcResult;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
+import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@NotThreadSafe
+final class VppWriteTransaction implements DOMDataWriteTransaction {
+
+    private static final Logger LOG = LoggerFactory.getLogger(VppWriteTransaction.class);
+    private final VppDataTree configDataTree;
+    private DataTreeModification modification;
+    private TransactionStatus status;
+
+    VppWriteTransaction(@Nonnull final VppDataTree configDataTree,
+                        @Nonnull final VppDataTreeSnapshot configSnapshot) {
+        this.configDataTree = Preconditions.checkNotNull(configDataTree, "configDataTree should not be null");
+        Preconditions.checkNotNull(configSnapshot, "configSnapshot should not be null");
+        // initialize transaction state:
+        modification = configSnapshot.newModification();
+        status = NEW;
+    }
+
+    VppWriteTransaction(@Nonnull final VppDataTree configDataTree) {
+        this(configDataTree, configDataTree.takeSnapshot());
+    }
+
+    private static void checkConfigurationWrite(final LogicalDatastoreType store) {
+        Preconditions.checkArgument(LogicalDatastoreType.CONFIGURATION == store, "Write is not supported for operational data store");
+    }
+
+    private void checkIsNew() {
+        Preconditions.checkState(status == NEW, "Transaction was submitted or canceled");
+        Preconditions.checkState(modification != null, "VPPDataTree modification should not be null");
+    }
+
+    @Override
+    public void put(final LogicalDatastoreType store, final YangInstanceIdentifier path,
+                    final NormalizedNode<?, ?> data) {
+        LOG.debug("VppWriteTransaction.put() store={}, path={}, data={}", store, path, data);
+        checkIsNew();
+        checkConfigurationWrite(store);
+        modification.write(path, data);
+    }
+
+    @Override
+    public void merge(final LogicalDatastoreType store, final YangInstanceIdentifier path,
+                      final NormalizedNode<?, ?> data) {
+        LOG.debug("VppWriteTransaction.merge() store={}, path={}, data={}", store, path, data);
+        checkIsNew();
+        checkConfigurationWrite(store);
+        modification.merge(path, data);
+    }
+
+    @Override
+    public boolean cancel() {
+        if (status != NEW) {
+            // only NEW transactions can be cancelled
+            return false;
+        } else {
+            status = CANCELED;
+            modification = null;
+            return true;
+        }
+    }
+
+    @Override
+    public void delete(LogicalDatastoreType store, final YangInstanceIdentifier path) {
+        LOG.debug("VppWriteTransaction.delete() store={}, path={}", store, path);
+        checkIsNew();
+        checkConfigurationWrite(store);
+        modification.delete(path);
+    }
+
+    @Override
+    public CheckedFuture<Void, TransactionCommitFailedException> submit() {
+        LOG.debug("VppWriteTransaction.submit()");
+        checkIsNew();
+
+        // seal transaction:
+        modification.ready();
+        status = SUBMITED;
+
+        try {
+            configDataTree.commit(modification);
+            status = COMMITED;
+        } catch (DataValidationFailedException | TranslationException e) {
+            status = FAILED;
+            LOG.error("Failed to commit VPP state modification", e);
+            return Futures.immediateFailedCheckedFuture(
+                    new TransactionCommitFailedException("Failed to validate DataTreeModification", e));
+        } finally {
+            modification = null;
+        }
+        return Futures.immediateCheckedFuture(null);
+    }
+
+    @Override
+    @Deprecated
+    public ListenableFuture<RpcResult<TransactionStatus>> commit() {
+        throw new UnsupportedOperationException("deprecated");
+    }
+
+    @Override
+    public Object getIdentifier() {
+        return this;
+    }
+}