Migrate ElanUtils to use NamedLocks
[netvirt.git] / elanmanager / impl / src / main / java / org / opendaylight / netvirt / elan / utils / ElanUtils.java
index 6076f036c66448a11ac14b9ddbb07445649adcbf..a25c8a25eed3c7b10a2475eca48ccbe96fbee4e6 100755 (executable)
@@ -7,6 +7,10 @@
  */
 package org.opendaylight.netvirt.elan.utils;
 
+import static java.util.Collections.emptyList;
+import static org.opendaylight.controller.md.sal.binding.api.WriteTransaction.CREATE_MISSING_PARENTS;
+import static org.opendaylight.genius.infra.Datastore.CONFIGURATION;
+
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Strings;
@@ -17,30 +21,37 @@ import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
+import edu.umd.cs.findbugs.annotations.CheckReturnValue;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import javax.inject.Inject;
 import javax.inject.Singleton;
 import org.apache.commons.lang3.StringUtils;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
 import org.opendaylight.controller.md.sal.binding.api.DataBroker;
 import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
-import org.opendaylight.controller.md.sal.binding.api.ReadTransaction;
 import org.opendaylight.controller.md.sal.binding.api.WriteTransaction;
 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.genius.infra.Datastore;
+import org.opendaylight.genius.infra.Datastore.Configuration;
+import org.opendaylight.genius.infra.Datastore.Operational;
 import org.opendaylight.genius.infra.ManagedNewTransactionRunner;
 import org.opendaylight.genius.infra.ManagedNewTransactionRunnerImpl;
+import org.opendaylight.genius.infra.TypedReadTransaction;
+import org.opendaylight.genius.infra.TypedReadWriteTransaction;
+import org.opendaylight.genius.infra.TypedWriteTransaction;
 import org.opendaylight.genius.interfacemanager.globals.InterfaceInfo;
-import org.opendaylight.genius.interfacemanager.globals.InterfaceServiceUtil;
 import org.opendaylight.genius.interfacemanager.interfaces.IInterfaceManager;
+import org.opendaylight.genius.itm.api.IITMProvider;
 import org.opendaylight.genius.itm.globals.ITMConstants;
 import org.opendaylight.genius.mdsalutil.ActionInfo;
 import org.opendaylight.genius.mdsalutil.FlowEntity;
@@ -62,9 +73,9 @@ import org.opendaylight.genius.mdsalutil.matches.MatchTunnelId;
 import org.opendaylight.genius.mdsalutil.packet.ARP;
 import org.opendaylight.genius.mdsalutil.packet.Ethernet;
 import org.opendaylight.genius.mdsalutil.packet.IPv4;
-import org.opendaylight.infrautils.utils.concurrent.JdkFutures;
-import org.opendaylight.infrautils.utils.concurrent.ListenableFutures;
-import org.opendaylight.netvirt.elan.ElanException;
+import org.opendaylight.infrautils.utils.concurrent.LoggingFutures;
+import org.opendaylight.infrautils.utils.concurrent.NamedLocks;
+import org.opendaylight.infrautils.utils.concurrent.NamedSimpleReentrantLock.Acquired;
 import org.opendaylight.netvirt.elan.arp.responder.ArpResponderUtil;
 import org.opendaylight.netvirt.elan.cache.ElanInterfaceCache;
 import org.opendaylight.netvirt.elanmanager.api.ElanHelper;
@@ -118,6 +129,9 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.genius.itm.rpcs.rev160406.I
 import org.opendaylight.yang.gen.v1.urn.opendaylight.genius.itm.rpcs.rev160406.RemoveTerminatingServiceActionsInput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.genius.itm.rpcs.rev160406.RemoveTerminatingServiceActionsInputBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.genius.itm.rpcs.rev160406.RemoveTerminatingServiceActionsOutput;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.GroupId;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.Group;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.GroupKey;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
@@ -133,7 +147,6 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.etree.rev16061
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.etree.rev160614.EtreeLeafTagNameBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanDpnInterfaces;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanForwardingTables;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanInstances;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanInterfaceForwardingEntries;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanInterfaces;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.elan.rev150602.ElanState;
@@ -177,8 +190,38 @@ import org.slf4j.LoggerFactory;
 
 @Singleton
 public class ElanUtils {
+    private static final class ElanLockName {
+        private final String macAddress;
+        private final BigInteger dpnId;
+        private final long elanTag;
+
+        ElanLockName(long elanTag, String macAddress, BigInteger dpnId) {
+            this.elanTag = elanTag;
+            this.macAddress = macAddress;
+            this.dpnId = dpnId;
+        }
+
+        @Override
+        public int hashCode() {
+            return 31 * Long.hashCode(elanTag) + Objects.hash(macAddress, dpnId);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (!(obj instanceof ElanLockName)) {
+                return false;
+            }
+            final ElanLockName other = (ElanLockName) obj;
+            return elanTag == other.elanTag && Objects.equals(macAddress, other.macAddress)
+                    && Objects.equals(dpnId, other.dpnId);
+        }
+    }
 
     private static final Logger LOG = LoggerFactory.getLogger(ElanUtils.class);
+    private static final NamedLocks<ElanLockName> ELAN_LOCKS = new NamedLocks<>();
 
     private final DataBroker broker;
     private final ManagedNewTransactionRunner txRunner;
@@ -190,6 +233,7 @@ public class ElanUtils {
     private final ElanItmUtils elanItmUtils;
     private final ElanEtreeUtils elanEtreeUtils;
     private final ElanInterfaceCache elanInterfaceCache;
+    private final IITMProvider iitmProvider;
 
     public static final FutureCallback<Void> DEFAULT_CALLBACK = new FutureCallback<Void>() {
         @Override
@@ -207,7 +251,7 @@ public class ElanUtils {
     public ElanUtils(DataBroker dataBroker, IMdsalApiManager mdsalManager,
             OdlInterfaceRpcService interfaceManagerRpcService, ItmRpcService itmRpcService, ElanConfig elanConfig,
             IInterfaceManager interfaceManager, ElanEtreeUtils elanEtreeUtils, ElanItmUtils elanItmUtils,
-            ElanInterfaceCache elanInterfaceCache) {
+            ElanInterfaceCache elanInterfaceCache, IITMProvider iitmProvider) {
         this.broker = dataBroker;
         this.txRunner = new ManagedNewTransactionRunnerImpl(dataBroker);
         this.mdsalManager = mdsalManager;
@@ -218,6 +262,7 @@ public class ElanUtils {
         this.elanEtreeUtils = elanEtreeUtils;
         this.elanItmUtils = elanItmUtils;
         this.elanInterfaceCache = elanInterfaceCache;
+        this.iitmProvider = iitmProvider;
     }
 
     public final Boolean isOpenstackVniSemanticsEnforced() {
@@ -255,7 +300,7 @@ public class ElanUtils {
 
     public static void releaseId(IdManagerService idManager, String poolName, String idKey) {
         ReleaseIdInput releaseIdInput = new ReleaseIdInputBuilder().setPoolName(poolName).setIdKey(idKey).build();
-        JdkFutures.addErrorLogging(idManager.releaseId(releaseIdInput), LOG, "Release Id");
+        LoggingFutures.addErrorLogging(idManager.releaseId(releaseIdInput), LOG, "Release Id");
     }
 
     /**
@@ -271,7 +316,7 @@ public class ElanUtils {
      */
     @Deprecated
     @SuppressWarnings("checkstyle:IllegalCatch")
-    public static <T extends DataObject> Optional<T> read(@Nonnull DataBroker broker,
+    public static <T extends DataObject> Optional<T> read(@NonNull DataBroker broker,
             LogicalDatastoreType datastoreType, InstanceIdentifier<T> path) {
         try (ReadOnlyTransaction tx = broker.newReadOnlyTransaction()) {
             return tx.read(datastoreType, path).get();
@@ -288,7 +333,7 @@ public class ElanUtils {
         }
     }
 
-    @SuppressWarnings("checkstyle:ForbiddenMethod")
+    @SuppressWarnings("checkstyle:ForbidCertainMethod")
     public static <T extends DataObject> void delete(DataBroker broker, LogicalDatastoreType datastoreType,
             InstanceIdentifier<T> path) {
         WriteTransaction tx = broker.newWriteOnlyTransaction();
@@ -296,33 +341,22 @@ public class ElanUtils {
         Futures.addCallback(tx.submit(), DEFAULT_CALLBACK, MoreExecutors.directExecutor());
     }
 
-    @SuppressWarnings("checkstyle:ForbiddenMethod")
-    public static <T extends DataObject> void delete(DataBroker broker, LogicalDatastoreType datastoreType,
-            InstanceIdentifier<T> path, FutureCallback<Void> callback) {
-        WriteTransaction tx = broker.newWriteOnlyTransaction();
-        tx.delete(datastoreType, path);
-        Futures.addCallback(tx.submit(), callback, MoreExecutors.directExecutor());
-    }
-
-    public static InstanceIdentifier<ElanInstance> getElanInstanceIdentifier() {
-        return InstanceIdentifier.builder(ElanInstances.class).child(ElanInstance.class).build();
-    }
-
     public static InstanceIdentifier<ElanInterface> getElanInterfaceConfigurationDataPathId(String interfaceName) {
         return InstanceIdentifier.builder(ElanInterfaces.class)
                 .child(ElanInterface.class, new ElanInterfaceKey(interfaceName)).build();
     }
 
     // elan-state Operational container
+    @Nullable
     public static Elan getElanByName(DataBroker broker, String elanInstanceName) {
         InstanceIdentifier<Elan> elanIdentifier = getElanInstanceOperationalDataPath(elanInstanceName);
         return MDSALUtil.read(broker, LogicalDatastoreType.OPERATIONAL, elanIdentifier).orNull();
     }
 
     @Nullable
-    public static Elan getElanByName(ReadTransaction tx, String elanInstanceName) throws ReadFailedException {
-        return tx.read(LogicalDatastoreType.OPERATIONAL,
-                getElanInstanceOperationalDataPath(elanInstanceName)).checkedGet().orNull();
+    public static Elan getElanByName(TypedReadTransaction<Operational> tx, String elanInstanceName)
+            throws ExecutionException, InterruptedException {
+        return tx.read(getElanInstanceOperationalDataPath(elanInstanceName)).get().orNull();
     }
 
     public static InstanceIdentifier<Elan> getElanInstanceOperationalDataPath(String elanInstanceName) {
@@ -330,16 +364,17 @@ public class ElanUtils {
     }
 
     // grouping of forwarding-entries
+    @Nullable
     public MacEntry getInterfaceMacEntriesOperationalDataPath(String interfaceName, PhysAddress physAddress) {
         InstanceIdentifier<MacEntry> existingMacEntryId = getInterfaceMacEntriesIdentifierOperationalDataPath(
                 interfaceName, physAddress);
         return read(broker, LogicalDatastoreType.OPERATIONAL, existingMacEntryId).orNull();
     }
 
-    public MacEntry getInterfaceMacEntriesOperationalDataPathFromId(InstanceIdentifier identifier) {
-        Optional<MacEntry> existingInterfaceMacEntry = read(broker,
-                LogicalDatastoreType.OPERATIONAL, identifier);
-        return existingInterfaceMacEntry.orNull();
+    @Nullable
+    public MacEntry getInterfaceMacEntriesOperationalDataPathFromId(TypedReadTransaction<Operational> tx,
+            InstanceIdentifier<MacEntry> identifier) throws ExecutionException, InterruptedException {
+        return tx.read(identifier).get().orNull();
     }
 
     public static InstanceIdentifier<MacEntry> getInterfaceMacEntriesIdentifierOperationalDataPath(String interfaceName,
@@ -356,16 +391,16 @@ public class ElanUtils {
         return read(broker, LogicalDatastoreType.OPERATIONAL, macId);
     }
 
-    public Optional<MacEntry> getMacEntryForElanInstance(ReadTransaction tx, String elanName, PhysAddress physAddress)
-            throws ReadFailedException {
+    public Optional<MacEntry> getMacEntryForElanInstance(TypedReadTransaction<Operational> tx, String elanName,
+            PhysAddress physAddress) throws ExecutionException, InterruptedException {
         InstanceIdentifier<MacEntry> macId = getMacEntryOperationalDataPath(elanName, physAddress);
-        return tx.read(LogicalDatastoreType.OPERATIONAL, macId).checkedGet();
+        return tx.read(macId).get();
     }
 
-    public MacEntry getMacEntryFromElanMacId(InstanceIdentifier identifier) {
-        Optional<MacEntry> existingInterfaceMacEntry = read(broker,
-                LogicalDatastoreType.OPERATIONAL, identifier);
-        return existingInterfaceMacEntry.orNull();
+    @Nullable
+    public MacEntry getMacEntryFromElanMacId(TypedReadTransaction<Operational> tx,
+            InstanceIdentifier<MacEntry> identifier) throws ExecutionException, InterruptedException {
+        return tx.read(identifier).get().orNull();
     }
 
     public static InstanceIdentifier<MacEntry> getMacEntryOperationalDataPath(String elanName,
@@ -391,25 +426,6 @@ public class ElanUtils {
         return read(dataBroker, LogicalDatastoreType.OPERATIONAL, elanInterfaceId).orNull();
     }
 
-    /**
-     * Gets the elan interface mac addresses.
-     *
-     * @param interfaceName
-     *            the interface name
-     * @return the elan interface mac addresses
-     */
-    public List<PhysAddress> getElanInterfaceMacAddresses(String interfaceName) {
-        List<PhysAddress> macAddresses = new ArrayList<>();
-        ElanInterfaceMac elanInterfaceMac = getElanInterfaceMacByInterfaceName(interfaceName);
-        if (elanInterfaceMac != null && elanInterfaceMac.getMacEntry() != null) {
-            List<MacEntry> macEntries = elanInterfaceMac.getMacEntry();
-            for (MacEntry macEntry : macEntries) {
-                macAddresses.add(macEntry.getMacAddress());
-            }
-        }
-        return macAddresses;
-    }
-
     public static InstanceIdentifier<ElanInterfaceMac> getElanInterfaceMacEntriesOperationalDataPath(
             String interfaceName) {
         return InstanceIdentifier.builder(ElanInterfaceForwardingEntries.class)
@@ -418,7 +434,7 @@ public class ElanUtils {
 
     /**
      * Returns the list of Interfaces that belong to an Elan on an specific DPN.
-     * Data retrieved from Elan's operational DS: elan-dpn-interfaces container
+     * Data retrieved from Elan's operational DS: elan-dpn-interfaces container.
      *
      * @param elanInstanceName
      *            name of the Elan to which the interfaces must belong to
@@ -426,6 +442,7 @@ public class ElanUtils {
      *            Id of the DPN where the interfaces are located
      * @return the elan interface Info
      */
+    @Nullable
     public DpnInterfaces getElanInterfaceInfoByElanDpn(String elanInstanceName, BigInteger dpId) {
         InstanceIdentifier<DpnInterfaces> elanDpnInterfacesId = getElanDpnInterfaceOperationalDataPath(elanInstanceName,
                 dpId);
@@ -451,6 +468,7 @@ public class ElanUtils {
     }
 
     // elan-tag-name-map Operational Container
+    @Nullable
     public ElanTagName getElanInfoByElanTag(long elanTag) {
         InstanceIdentifier<ElanTagName> elanId = getElanInfoEntriesOperationalDataPath(elanTag);
         Optional<ElanTagName> existingElanInfo = read(broker,
@@ -479,11 +497,13 @@ public class ElanUtils {
                 .child(ElanDpnInterfacesList.class, new ElanDpnInterfacesListKey(elanInstanceName)).build();
     }
 
+    @Nullable
     public ElanDpnInterfacesList getElanDpnInterfacesList(String elanName) {
         InstanceIdentifier<ElanDpnInterfacesList> elanDpnInterfaceId = getElanDpnOperationDataPath(elanName);
         return read(broker, LogicalDatastoreType.OPERATIONAL, elanDpnInterfaceId).orNull();
     }
 
+    @Nullable
     public ElanDpnInterfaces getElanDpnInterfacesList() {
         InstanceIdentifier<ElanDpnInterfaces> elanDpnInterfaceId = InstanceIdentifier.builder(ElanDpnInterfaces.class)
                 .build();
@@ -499,7 +519,7 @@ public class ElanUtils {
      *            the elan instance name
      * @return list of dpIds
      */
-    @Nonnull
+    @NonNull
     public List<BigInteger> getParticipatingDpnsInElanInstance(String elanInstanceName) {
         List<BigInteger> dpIds = new ArrayList<>();
         InstanceIdentifier<ElanDpnInterfacesList> elanDpnInterfaceId = getElanDpnOperationDataPath(elanInstanceName);
@@ -508,46 +528,13 @@ public class ElanUtils {
         if (!existingElanDpnInterfaces.isPresent()) {
             return dpIds;
         }
-        List<DpnInterfaces> dpnInterfaces = existingElanDpnInterfaces.get().getDpnInterfaces();
+        List<DpnInterfaces> dpnInterfaces = existingElanDpnInterfaces.get().nonnullDpnInterfaces();
         for (DpnInterfaces dpnInterface : dpnInterfaces) {
             dpIds.add(dpnInterface.getDpId());
         }
         return dpIds;
     }
 
-    /**
-     * To check given dpId is already present in Elan instance. This can be used
-     * to program flow entry in external tunnel table when a new access port
-     * added for first time into the ELAN instance
-     *
-     * @param dpId
-     *            the dp id
-     * @param elanInstanceName
-     *            the elan instance name
-     * @return true if dpId is already present, otherwise return false
-     */
-    public boolean isDpnAlreadyPresentInElanInstance(BigInteger dpId, String elanInstanceName) {
-        InstanceIdentifier<ElanDpnInterfacesList> elanDpnInterfaceId = getElanDpnOperationDataPath(elanInstanceName);
-        Optional<ElanDpnInterfacesList> existingElanDpnInterfaces = read(broker,
-                LogicalDatastoreType.OPERATIONAL, elanDpnInterfaceId);
-        if (!existingElanDpnInterfaces.isPresent()) {
-            return false;
-        }
-        List<DpnInterfaces> dpnInterfaces = existingElanDpnInterfaces.get().getDpnInterfaces();
-        for (DpnInterfaces dpnInterface : dpnInterfaces) {
-            if (dpnInterface.getDpId().equals(dpId)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    public ElanForwardingTables getElanForwardingList() {
-        InstanceIdentifier<ElanForwardingTables> elanForwardingTableId = InstanceIdentifier
-                .builder(ElanForwardingTables.class).build();
-        return read(broker, LogicalDatastoreType.OPERATIONAL, elanForwardingTableId).orNull();
-    }
-
     public static long getElanRemoteBroadCastGroupID(long elanTag) {
         return ElanConstants.ELAN_GID_MIN + elanTag % ElanConstants.ELAN_GID_MIN * 2;
     }
@@ -559,6 +546,7 @@ public class ElanUtils {
      *            the elan name
      * @return the elan mac table
      */
+    @Nullable
     public MacTable getElanMacTable(String elanName) {
         return getElanMacTable(broker, elanName);
     }
@@ -605,12 +593,11 @@ public class ElanUtils {
      *            true if remote dmac flows should be configured as well
      * @param writeFlowGroupTx
      *            the flow group tx
-     * @throws ElanException in case of issues creating the flow objects
      */
     public void setupMacFlows(ElanInstance elanInfo, InterfaceInfo interfaceInfo,
                               long macTimeout, String macAddress, boolean configureRemoteFlows,
-                              WriteTransaction writeFlowGroupTx) throws ElanException {
-        synchronized (getElanMacDPNKey(elanInfo.getElanTag(), macAddress, interfaceInfo.getDpId())) {
+                              TypedWriteTransaction<Configuration> writeFlowGroupTx) {
+        try (Acquired lock = lockElanMacDPN(elanInfo.getElanTag(), macAddress, interfaceInfo.getDpId())) {
             setupKnownSmacFlow(elanInfo, interfaceInfo, macTimeout, macAddress, mdsalManager,
                 writeFlowGroupTx);
             setupOrigDmacFlows(elanInfo, interfaceInfo, macAddress, configureRemoteFlows, mdsalManager,
@@ -619,7 +606,7 @@ public class ElanUtils {
     }
 
     public void setupDMacFlowOnRemoteDpn(ElanInstance elanInfo, InterfaceInfo interfaceInfo, BigInteger dstDpId,
-                                         String macAddress, WriteTransaction writeFlowTx) throws ElanException {
+                                         String macAddress, TypedWriteTransaction<Configuration> writeFlowTx) {
         String elanInstanceName = elanInfo.getElanInstanceName();
         setupRemoteDmacFlow(dstDpId, interfaceInfo.getDpId(), interfaceInfo.getInterfaceTag(), elanInfo.getElanTag(),
                 macAddress, elanInstanceName, writeFlowTx, interfaceInfo.getInterfaceName(), elanInfo);
@@ -633,9 +620,10 @@ public class ElanUtils {
      * learnt.
      */
     private void setupKnownSmacFlow(ElanInstance elanInfo, InterfaceInfo interfaceInfo, long macTimeout,
-            String macAddress, IMdsalApiManager mdsalApiManager, WriteTransaction writeFlowGroupTx) {
+            String macAddress, IMdsalApiManager mdsalApiManager,
+            TypedWriteTransaction<Configuration> writeFlowGroupTx) {
         FlowEntity flowEntity = buildKnownSmacFlow(elanInfo, interfaceInfo, macTimeout, macAddress);
-        mdsalApiManager.addFlowToTx(flowEntity, writeFlowGroupTx);
+        mdsalApiManager.addFlow(writeFlowGroupTx, flowEntity);
         LOG.debug("Known Smac flow entry created for elan Name:{}, logical Interface port:{} and mac address:{}",
                 elanInfo.getElanInstanceName(), elanInfo.getDescription(), macAddress);
     }
@@ -674,7 +662,7 @@ public class ElanUtils {
         if (etreeInterface == null || etreeInterface.getEtreeInterfaceType() == EtreeInterfaceType.Root) {
             return elanInfo.getElanTag();
         } else { // Leaf
-            EtreeInstance etreeInstance = elanInfo.getAugmentation(EtreeInstance.class);
+            EtreeInstance etreeInstance = elanInfo.augmentation(EtreeInstance.class);
             if (etreeInstance == null) {
                 LOG.warn("EtreeInterface {} is connected to a non-Etree network: {}",
                          interfaceInfo.getInterfaceName(), elanInfo.getElanInstanceName());
@@ -698,7 +686,7 @@ public class ElanUtils {
      *            the writeFLowGroup tx
      */
     public void setupTermDmacFlows(InterfaceInfo interfaceInfo, IMdsalApiManager mdsalApiManager,
-                                   WriteTransaction writeFlowGroupTx) {
+                                   TypedWriteTransaction<Configuration> writeFlowGroupTx) {
         BigInteger dpId = interfaceInfo.getDpId();
         int lportTag = interfaceInfo.getInterfaceTag();
         Flow flow = MDSALUtil.buildFlowNew(NwConstants.INTERNAL_TUNNEL_TABLE,
@@ -707,7 +695,7 @@ public class ElanUtils {
                 ITMConstants.COOKIE_ITM.add(BigInteger.valueOf(lportTag)),
                 getTunnelIdMatchForFilterEqualsLPortTag(lportTag),
                 getInstructionsInPortForOutGroup(interfaceInfo.getInterfaceName()));
-        mdsalApiManager.addFlowToTx(dpId, flow, writeFlowGroupTx);
+        mdsalApiManager.addFlow(writeFlowGroupTx, dpId, flow);
         LOG.debug("Terminating service table flow entry created on dpn:{} for logical Interface port:{}", dpId,
                 interfaceInfo.getPortName());
     }
@@ -723,7 +711,7 @@ public class ElanUtils {
      * @return the Internal tunnel
      */
     public static String getIntTunnelTableFlowRef(short tableId, int elanTag) {
-        return new StringBuffer().append(tableId).append(elanTag).toString();
+        return new StringBuilder().append(tableId).append(elanTag).toString();
     }
 
     /**
@@ -773,7 +761,8 @@ public class ElanUtils {
      * @return the egress actions for interface
      */
     @SuppressWarnings("checkstyle:IllegalCatch")
-    public List<Action> getEgressActionsForInterface(String ifName, Long tunnelKey) {
+    @NonNull
+    public List<Action> getEgressActionsForInterface(String ifName, @Nullable Long tunnelKey) {
         List<Action> listAction = new ArrayList<>();
         try {
             GetEgressActionsForInterfaceInput getEgressActionInput = new GetEgressActionsForInterfaceInputBuilder()
@@ -785,8 +774,7 @@ public class ElanUtils {
                 LOG.debug("RPC Call to Get egress actions for interface {} returned with Errors {}", ifName,
                         rpcResult.getErrors());
             } else {
-                List<Action> actions = rpcResult.getResult().getAction();
-                listAction = actions;
+                listAction = rpcResult.getResult().nonnullAction();
             }
         } catch (Exception e) {
             LOG.warn("Exception when egress actions for interface {}", ifName, e);
@@ -796,8 +784,7 @@ public class ElanUtils {
 
     private void setupOrigDmacFlows(ElanInstance elanInfo, InterfaceInfo interfaceInfo, String macAddress,
                                     boolean configureRemoteFlows, IMdsalApiManager mdsalApiManager,
-                                    WriteTransaction writeFlowGroupTx)
-                                    throws ElanException {
+                                    TypedWriteTransaction<Configuration> writeFlowGroupTx) {
         BigInteger dpId = interfaceInfo.getDpId();
         String ifName = interfaceInfo.getInterfaceName();
         long ifTag = interfaceInfo.getInterfaceTag();
@@ -817,7 +804,7 @@ public class ElanUtils {
         List<DpnInterfaces> elanDpns = getInvolvedDpnsInElan(elanInstanceName);
         for (DpnInterfaces elanDpn : elanDpns) {
 
-            if (elanDpn.getDpId().equals(dpId)) {
+            if (Objects.equals(elanDpn.getDpId(), dpId)) {
                 continue;
             }
 
@@ -842,28 +829,28 @@ public class ElanUtils {
         // TODO: Make sure that the same is performed against the ElanDevices.
     }
 
-    @Nonnull
+    @NonNull
     public List<DpnInterfaces> getInvolvedDpnsInElan(String elanName) {
         return getElanDPNByName(elanName);
     }
 
-    @Nonnull
+    @NonNull
     public List<DpnInterfaces> getElanDPNByName(String elanInstanceName) {
         InstanceIdentifier<ElanDpnInterfacesList> elanIdentifier = getElanDpnOperationDataPath(elanInstanceName);
         return MDSALUtil.read(broker, LogicalDatastoreType.OPERATIONAL, elanIdentifier).toJavaUtil().map(
-                ElanDpnInterfacesList::getDpnInterfaces).orElse(Collections.emptyList());
+                ElanDpnInterfacesList::getDpnInterfaces).orElse(emptyList());
     }
 
     private void setupLocalDmacFlow(long elanTag, BigInteger dpId, String ifName, String macAddress,
-            ElanInstance elanInfo, IMdsalApiManager mdsalApiManager, long ifTag, WriteTransaction writeFlowGroupTx) {
+            ElanInstance elanInfo, IMdsalApiManager mdsalApiManager, long ifTag,
+            TypedWriteTransaction<Configuration> writeFlowGroupTx) {
         Flow flowEntity = buildLocalDmacFlowEntry(elanTag, dpId, ifName, macAddress, elanInfo, ifTag);
-        mdsalApiManager.addFlowToTx(dpId, flowEntity, writeFlowGroupTx);
-        installEtreeLocalDmacFlow(elanTag, dpId, ifName, macAddress, elanInfo,
-                ifTag, writeFlowGroupTx);
+        mdsalApiManager.addFlow(writeFlowGroupTx, dpId, flowEntity);
+        installEtreeLocalDmacFlow(elanTag, dpId, ifName, macAddress, elanInfo, ifTag, writeFlowGroupTx);
     }
 
     private void installEtreeLocalDmacFlow(long elanTag, BigInteger dpId, String ifName, String macAddress,
-            ElanInstance elanInfo, long ifTag, WriteTransaction writeFlowGroupTx) {
+            ElanInstance elanInfo, long ifTag, TypedWriteTransaction<Configuration> writeFlowGroupTx) {
         EtreeInterface etreeInterface = elanInterfaceCache.getEtreeInterface(ifName).orNull();
         if (etreeInterface != null && etreeInterface.getEtreeInterfaceType() == EtreeInterfaceType.Root) {
             EtreeLeafTagName etreeTagName = elanEtreeUtils.getEtreeLeafTagByElanTag(elanTag);
@@ -873,7 +860,7 @@ public class ElanUtils {
             } else {
                 Flow flowEntity = buildLocalDmacFlowEntry(etreeTagName.getEtreeLeafTag().getValue(), dpId, ifName,
                         macAddress, elanInfo, ifTag);
-                mdsalManager.addFlowToTx(dpId, flowEntity, writeFlowGroupTx);
+                mdsalManager.addFlow(writeFlowGroupTx, dpId, flowEntity);
             }
         }
     }
@@ -937,9 +924,9 @@ public class ElanUtils {
         return flow;
     }
 
-    public void setupRemoteDmacFlow(BigInteger srcDpId, BigInteger destDpId, int lportTag, long elanTag, String
-            macAddress, String displayName, WriteTransaction writeFlowGroupTx, String interfaceName, ElanInstance
-            elanInstance) throws ElanException {
+    public void setupRemoteDmacFlow(BigInteger srcDpId, BigInteger destDpId, int lportTag, long elanTag,
+            String macAddress, String displayName, TypedWriteTransaction<Configuration> writeFlowGroupTx,
+            String interfaceName, ElanInstance elanInstance) {
         if (interfaceManager.isExternalInterface(interfaceName)) {
             LOG.debug("Ignoring install remote DMAC {} flow on provider interface {} elan {}",
                     macAddress, interfaceName, elanInstance.getElanInstanceName());
@@ -952,14 +939,15 @@ public class ElanUtils {
                 ? getVxlanSegmentationId(elanInstance) : 0;
         flowEntity = buildRemoteDmacFlowEntry(srcDpId, destDpId, lportTagOrVni, elanTag, macAddress, displayName,
                 elanInstance);
-        mdsalManager.addFlowToTx(srcDpId, flowEntity, writeFlowGroupTx);
+        mdsalManager.addFlow(writeFlowGroupTx, srcDpId, flowEntity);
         setupEtreeRemoteDmacFlow(srcDpId, destDpId, lportTagOrVni, elanTag, macAddress, displayName, interfaceName,
                 writeFlowGroupTx, elanInstance);
     }
 
     private void setupEtreeRemoteDmacFlow(BigInteger srcDpId, BigInteger destDpId, long lportTagOrVni, long elanTag,
                                           String macAddress, String displayName, String interfaceName,
-                                          WriteTransaction writeFlowGroupTx, ElanInstance elanInstance) {
+                                          TypedWriteTransaction<Configuration> writeFlowGroupTx,
+                                          ElanInstance elanInstance) {
         Flow flowEntity;
         EtreeInterface etreeInterface = elanInterfaceCache.getEtreeInterface(interfaceName).orNull();
         if (etreeInterface != null && etreeInterface.getEtreeInterfaceType() == EtreeInterfaceType.Root) {
@@ -970,7 +958,7 @@ public class ElanUtils {
             } else {
                 flowEntity = buildRemoteDmacFlowEntry(srcDpId, destDpId, lportTagOrVni,
                         etreeTagName.getEtreeLeafTag().getValue(), macAddress, displayName, elanInstance);
-                mdsalManager.addFlowToTx(srcDpId, flowEntity, writeFlowGroupTx);
+                mdsalManager.addFlow(writeFlowGroupTx, srcDpId, flowEntity);
             }
         }
     }
@@ -1009,15 +997,15 @@ public class ElanUtils {
         // List of Action for the provided Source and Destination DPIDs
         try {
             List<Action> actions = null;
-            if (isVlan(elanInstance) || isFlat(elanInstance)) {
+            if (isVxlanNetworkOrVxlanSegment(elanInstance)) {
+                actions = elanItmUtils.getInternalTunnelItmEgressAction(srcDpId, destDpId, lportTagOrVni);
+            } else if (isVlan(elanInstance) || isFlat(elanInstance)) {
                 String interfaceName = getExternalElanInterface(elanInstance.getElanInstanceName(), srcDpId);
                 if (null == interfaceName) {
                     LOG.info("buildRemoteDmacFlowEntry: Could not find interfaceName for {} {}", srcDpId,
-                        elanInstance);
+                            elanInstance);
                 }
                 actions = getEgressActionsForInterface(interfaceName, null);
-            } else if (isVxlanNetworkOrVxlanSegment(elanInstance)) {
-                actions = elanItmUtils.getInternalTunnelItmEgressAction(srcDpId, destDpId, lportTagOrVni);
             }
             mkInstructions.add(MDSALUtil.buildApplyActionsInstruction(actions));
         } catch (Exception e) {
@@ -1037,18 +1025,20 @@ public class ElanUtils {
     }
 
     public void deleteMacFlows(@Nullable ElanInstance elanInfo, @Nullable InterfaceInfo interfaceInfo,
-            MacEntry macEntry, WriteTransaction deleteFlowGroupTx) {
+            MacEntry macEntry, TypedReadWriteTransaction<Configuration> flowTx)
+            throws ExecutionException, InterruptedException {
         if (elanInfo == null || interfaceInfo == null) {
             return;
         }
         String macAddress = macEntry.getMacAddress().getValue();
-        synchronized (getElanMacDPNKey(elanInfo.getElanTag(), macAddress, interfaceInfo.getDpId())) {
-            deleteMacFlows(elanInfo, interfaceInfo, macAddress, /* alsoDeleteSMAC */ true, deleteFlowGroupTx);
+        try (Acquired lock = lockElanMacDPN(elanInfo.getElanTag(), macAddress, interfaceInfo.getDpId())) {
+            deleteMacFlows(elanInfo, interfaceInfo, macAddress, /* alsoDeleteSMAC */ true, flowTx);
         }
     }
 
     public void deleteMacFlows(ElanInstance elanInfo, InterfaceInfo interfaceInfo, String macAddress,
-            boolean deleteSmac, WriteTransaction deleteFlowGroupTx) {
+            boolean deleteSmac, TypedReadWriteTransaction<Configuration> flowTx)
+            throws ExecutionException, InterruptedException {
         String elanInstanceName = elanInfo.getElanInstanceName();
         List<DpnInterfaces> remoteFEs = getInvolvedDpnsInElan(elanInstanceName);
         BigInteger srcdpId = interfaceInfo.getDpId();
@@ -1057,40 +1047,39 @@ public class ElanUtils {
             Long elanTag = elanInfo.getElanTag();
             BigInteger dstDpId = dpnInterface.getDpId();
             if (executeDeleteMacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, elanInstanceName, srcdpId,
-                    elanTag, dstDpId, deleteFlowGroupTx)) {
+                    elanTag, dstDpId, flowTx)) {
                 isFlowsRemovedInSrcDpn = true;
             }
             executeEtreeDeleteMacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, elanInstanceName, srcdpId,
-                    elanTag, dstDpId, deleteFlowGroupTx);
+                    elanTag, dstDpId, flowTx);
         }
         if (!isFlowsRemovedInSrcDpn) {
-            deleteSmacAndDmacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, deleteFlowGroupTx);
+            deleteSmacAndDmacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, flowTx);
         }
     }
 
     private void executeEtreeDeleteMacFlows(ElanInstance elanInfo, InterfaceInfo interfaceInfo, String macAddress,
             boolean deleteSmac, String elanInstanceName, BigInteger srcdpId, Long elanTag, BigInteger dstDpId,
-            WriteTransaction deleteFlowGroupTx) {
+            TypedReadWriteTransaction<Configuration> flowTx) throws ExecutionException, InterruptedException {
         EtreeLeafTagName etreeLeafTag = elanEtreeUtils.getEtreeLeafTagByElanTag(elanTag);
         if (etreeLeafTag != null) {
             executeDeleteMacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, elanInstanceName, srcdpId,
-                    etreeLeafTag.getEtreeLeafTag().getValue(), dstDpId, deleteFlowGroupTx);
+                    etreeLeafTag.getEtreeLeafTag().getValue(), dstDpId, flowTx);
         }
     }
 
     private boolean executeDeleteMacFlows(ElanInstance elanInfo, InterfaceInfo interfaceInfo, String macAddress,
             boolean deleteSmac, String elanInstanceName, BigInteger srcdpId, Long elanTag, BigInteger dstDpId,
-            WriteTransaction deleteFlowGroupTx) {
+            TypedReadWriteTransaction<Configuration> flowTx) throws ExecutionException, InterruptedException {
         boolean isFlowsRemovedInSrcDpn = false;
         if (dstDpId.equals(srcdpId)) {
             isFlowsRemovedInSrcDpn = true;
-            deleteSmacAndDmacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, deleteFlowGroupTx);
+            deleteSmacAndDmacFlows(elanInfo, interfaceInfo, macAddress, deleteSmac, flowTx);
         } else if (isDpnPresent(dstDpId)) {
             mdsalManager
-                    .removeFlowToTx(dstDpId,
-                            MDSALUtil.buildFlow(NwConstants.ELAN_DMAC_TABLE, getKnownDynamicmacFlowRef(
-                                    NwConstants.ELAN_DMAC_TABLE, dstDpId, srcdpId, macAddress, elanTag)),
-                            deleteFlowGroupTx);
+                .removeFlow(flowTx, dstDpId,
+                    MDSALUtil.buildFlow(NwConstants.ELAN_DMAC_TABLE, getKnownDynamicmacFlowRef(
+                        NwConstants.ELAN_DMAC_TABLE, dstDpId, srcdpId, macAddress, elanTag)));
             LOG.debug("Dmac flow entry deleted for elan:{}, logical interface port:{} and mac address:{} on dpn:{}",
                     elanInstanceName, interfaceInfo.getPortName(), macAddress, dstDpId);
         }
@@ -1098,22 +1087,21 @@ public class ElanUtils {
     }
 
     private void deleteSmacAndDmacFlows(ElanInstance elanInfo, InterfaceInfo interfaceInfo, String macAddress,
-            boolean deleteSmac, WriteTransaction deleteFlowGroupTx) {
+            boolean deleteSmac, TypedReadWriteTransaction<Configuration> flowTx)
+            throws ExecutionException, InterruptedException {
         String elanInstanceName = elanInfo.getElanInstanceName();
         long ifTag = interfaceInfo.getInterfaceTag();
         BigInteger srcdpId = interfaceInfo.getDpId();
         Long elanTag = elanInfo.getElanTag();
         if (deleteSmac) {
             mdsalManager
-                    .removeFlowToTx(srcdpId,
+                    .removeFlow(flowTx, srcdpId,
                             MDSALUtil.buildFlow(NwConstants.ELAN_SMAC_TABLE, getKnownDynamicmacFlowRef(
-                                    NwConstants.ELAN_SMAC_TABLE, srcdpId, ifTag, macAddress, elanTag)),
-                            deleteFlowGroupTx);
+                                    NwConstants.ELAN_SMAC_TABLE, srcdpId, ifTag, macAddress, elanTag)));
         }
-        mdsalManager.removeFlowToTx(srcdpId,
-                MDSALUtil.buildFlow(NwConstants.ELAN_DMAC_TABLE,
-                        getKnownDynamicmacFlowRef(NwConstants.ELAN_DMAC_TABLE, srcdpId, ifTag, macAddress, elanTag)),
-                deleteFlowGroupTx);
+        mdsalManager.removeFlow(flowTx, srcdpId,
+            MDSALUtil.buildFlow(NwConstants.ELAN_DMAC_TABLE,
+                getKnownDynamicmacFlowRef(NwConstants.ELAN_DMAC_TABLE, srcdpId, ifTag, macAddress, elanTag)));
         LOG.debug("All the required flows deleted for elan:{}, logical Interface port:{} and MAC address:{} on dpn:{}",
                 elanInstanceName, interfaceInfo.getPortName(), macAddress, srcdpId);
     }
@@ -1128,32 +1116,31 @@ public class ElanUtils {
      *            the elan instance added
      * @param elanInterfaces
      *            the elan interfaces
-     * @param tx
+     * @param operTx
      *            transaction
      *
      * @return the updated ELAN instance.
      */
     public static ElanInstance updateOperationalDataStore(IdManagerService idManager,
-            ElanInstance elanInstanceAdded, List<String> elanInterfaces, WriteTransaction tx) {
+            ElanInstance elanInstanceAdded, List<String> elanInterfaces, TypedWriteTransaction<Configuration> confTx,
+            TypedWriteTransaction<Operational> operTx) {
         String elanInstanceName = elanInstanceAdded.getElanInstanceName();
         Long elanTag = elanInstanceAdded.getElanTag();
         if (elanTag == null || elanTag == 0L) {
             elanTag = retrieveNewElanTag(idManager, elanInstanceName);
         }
         Elan elanInfo = new ElanBuilder().setName(elanInstanceName).setElanInterfaces(elanInterfaces)
-                .setKey(new ElanKey(elanInstanceName)).build();
+                .withKey(new ElanKey(elanInstanceName)).build();
 
         // Add the ElanState in the elan-state operational data-store
-        tx.put(LogicalDatastoreType.OPERATIONAL, getElanInstanceOperationalDataPath(elanInstanceName),
-                elanInfo, WriteTransaction.CREATE_MISSING_PARENTS);
+        operTx.put(getElanInstanceOperationalDataPath(elanInstanceName), elanInfo, CREATE_MISSING_PARENTS);
 
         // Add the ElanMacTable in the elan-mac-table operational data-store
-        MacTable elanMacTable = new MacTableBuilder().setKey(new MacTableKey(elanInstanceName)).build();
-        tx.put(LogicalDatastoreType.OPERATIONAL, getElanMacTableOperationalDataPath(elanInstanceName),
-                elanMacTable, WriteTransaction.CREATE_MISSING_PARENTS);
+        MacTable elanMacTable = new MacTableBuilder().withKey(new MacTableKey(elanInstanceName)).build();
+        operTx.put(getElanMacTableOperationalDataPath(elanInstanceName), elanMacTable, CREATE_MISSING_PARENTS);
 
         ElanTagNameBuilder elanTagNameBuilder = new ElanTagNameBuilder().setElanTag(elanTag)
-                .setKey(new ElanTagNameKey(elanTag)).setName(elanInstanceName);
+                .withKey(new ElanTagNameKey(elanTag)).setName(elanInstanceName);
         long etreeLeafTag = -1;
         if (isEtreeInstance(elanInstanceAdded)) {
             etreeLeafTag = retrieveNewElanTag(idManager,elanInstanceName + ElanConstants
@@ -1161,14 +1148,13 @@ public class ElanUtils {
             EtreeLeafTagName etreeLeafTagName = new EtreeLeafTagNameBuilder()
                     .setEtreeLeafTag(new EtreeLeafTag(etreeLeafTag)).build();
             elanTagNameBuilder.addAugmentation(EtreeLeafTagName.class, etreeLeafTagName);
-            addTheLeafTagAsElanTag(elanInstanceName, etreeLeafTag, tx);
+            addTheLeafTagAsElanTag(elanInstanceName, etreeLeafTag, operTx);
         }
         ElanTagName elanTagName = elanTagNameBuilder.build();
 
         // Add the ElanTag to ElanName in the elan-tag-name Operational
         // data-store
-        tx.put(LogicalDatastoreType.OPERATIONAL,
-                getElanInfoEntriesOperationalDataPath(elanTag), elanTagName);
+        operTx.put(getElanInfoEntriesOperationalDataPath(elanTag), elanTagName);
 
         // Updates the ElanInstance Config DS by setting the just acquired
         // elanTag
@@ -1176,27 +1162,27 @@ public class ElanUtils {
                 .setDescription(elanInstanceAdded.getDescription())
                 .setMacTimeout(elanInstanceAdded.getMacTimeout() == null
                         ? Long.valueOf(ElanConstants.DEFAULT_MAC_TIME_OUT) : elanInstanceAdded.getMacTimeout())
-                .setKey(elanInstanceAdded.getKey()).setElanTag(elanTag);
+                .withKey(elanInstanceAdded.key()).setElanTag(elanTag);
         if (isEtreeInstance(elanInstanceAdded)) {
             EtreeInstance etreeInstance = new EtreeInstanceBuilder().setEtreeLeafTagVal(new EtreeLeafTag(etreeLeafTag))
                     .build();
             elanInstanceBuilder.addAugmentation(EtreeInstance.class, etreeInstance);
         }
         ElanInstance elanInstanceWithTag = elanInstanceBuilder.build();
-        tx.merge(LogicalDatastoreType.CONFIGURATION, ElanHelper.getElanInstanceConfigurationDataPath(elanInstanceName),
-                elanInstanceWithTag, WriteTransaction.CREATE_MISSING_PARENTS);
+        confTx.merge(ElanHelper.getElanInstanceConfigurationDataPath(elanInstanceName), elanInstanceWithTag,
+            CREATE_MISSING_PARENTS);
         return elanInstanceWithTag;
     }
 
-    private static void addTheLeafTagAsElanTag(String elanInstanceName, long etreeLeafTag, WriteTransaction tx) {
+    private static void addTheLeafTagAsElanTag(String elanInstanceName, long etreeLeafTag,
+            TypedWriteTransaction<Operational> tx) {
         ElanTagName etreeTagAsElanTag = new ElanTagNameBuilder().setElanTag(etreeLeafTag)
-                .setKey(new ElanTagNameKey(etreeLeafTag)).setName(elanInstanceName).build();
-        tx.put(LogicalDatastoreType.OPERATIONAL,
-                getElanInfoEntriesOperationalDataPath(etreeLeafTag), etreeTagAsElanTag);
+                .withKey(new ElanTagNameKey(etreeLeafTag)).setName(elanInstanceName).build();
+        tx.put(getElanInfoEntriesOperationalDataPath(etreeLeafTag), etreeTagAsElanTag);
     }
 
     private static boolean isEtreeInstance(ElanInstance elanInstanceAdded) {
-        return elanInstanceAdded.getAugmentation(EtreeInstance.class) != null;
+        return elanInstanceAdded.augmentation(EtreeInstance.class) != null;
     }
 
     public boolean isDpnPresent(BigInteger dpnId) {
@@ -1208,11 +1194,6 @@ public class ElanUtils {
         return read(broker, LogicalDatastoreType.CONFIGURATION, node).isPresent();
     }
 
-    public static ServicesInfo getServiceInfo(String elanInstanceName, String interfaceName) {
-        return InterfaceServiceUtil.buildServiceInfo(elanInstanceName + "." + interfaceName,
-                ElanConstants.ELAN_SERVICE_PRIORITY);
-    }
-
     public static String getElanServiceName(String elanName, String interfaceName) {
         return "elan." + elanName + interfaceName;
     }
@@ -1221,7 +1202,7 @@ public class ElanUtils {
             BigInteger cookie, List<Instruction> instructions) {
         StypeOpenflowBuilder augBuilder = new StypeOpenflowBuilder().setFlowCookie(cookie).setFlowPriority(flowPriority)
                 .setInstruction(instructions);
-        return new BoundServicesBuilder().setKey(new BoundServicesKey(servicePriority)).setServiceName(serviceName)
+        return new BoundServicesBuilder().withKey(new BoundServicesKey(servicePriority)).setServiceName(serviceName)
                 .setServicePriority(servicePriority).setServiceType(ServiceTypeFlowBased.class)
                 .addAugmentation(StypeOpenflow.class, augBuilder.build()).build();
     }
@@ -1271,6 +1252,7 @@ public class ElanUtils {
      *            the datastore type
      * @return the external tunnel
      */
+    @Nullable
     public ExternalTunnel getExternalTunnel(String sourceDevice, String destinationDevice,
             LogicalDatastoreType datastoreType) {
         Class<? extends TunnelTypeBase> tunType = TunnelTypeVxlan.class;
@@ -1288,6 +1270,7 @@ public class ElanUtils {
      *            the datastore type
      * @return the external tunnel
      */
+    @Nullable
     public ExternalTunnel getExternalTunnel(String interfaceName, LogicalDatastoreType datastoreType) {
         ExternalTunnel externalTunnel = null;
         List<ExternalTunnel> externalTunnels = getAllExternalTunnels(datastoreType);
@@ -1310,7 +1293,7 @@ public class ElanUtils {
     public List<ExternalTunnel> getAllExternalTunnels(LogicalDatastoreType datastoreType) {
         InstanceIdentifier<ExternalTunnelList> iid = InstanceIdentifier.builder(ExternalTunnelList.class).build();
         return read(broker, datastoreType, iid).toJavaUtil().map(ExternalTunnelList::getExternalTunnel).orElse(
-                Collections.emptyList());
+                emptyList());
     }
 
     public static List<MatchInfo> buildMatchesForElanTagShFlagAndDstMac(long elanTag, boolean shFlag, String macAddr) {
@@ -1350,13 +1333,10 @@ public class ElanUtils {
      *            the data broker
      * @return the interface state from oper ds
      */
-    public static org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang
-        .ietf.interfaces.rev140508.interfaces.state.Interface getInterfaceStateFromOperDS(
-            String interfaceName, DataBroker dataBroker) {
-        InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang
-            .ietf.interfaces.rev140508.interfaces.state.Interface> ifStateId = createInterfaceStateInstanceIdentifier(
-                interfaceName);
-        return MDSALUtil.read(dataBroker, LogicalDatastoreType.OPERATIONAL, ifStateId).orNull();
+    public static org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.state
+            .@Nullable Interface getInterfaceStateFromOperDS(String interfaceName, DataBroker dataBroker) {
+        return MDSALUtil.read(dataBroker, LogicalDatastoreType.OPERATIONAL,
+            createInterfaceStateInstanceIdentifier(interfaceName)).orNull();
     }
 
     /**
@@ -1380,16 +1360,15 @@ public class ElanUtils {
         return idBuilder.build();
     }
 
-    public static CheckedFuture<Void, TransactionCommitFailedException> waitForTransactionToComplete(
-            WriteTransaction tx) {
-        CheckedFuture<Void, TransactionCommitFailedException> futures = tx.submit();
+    @CheckReturnValue
+    public static ListenableFuture<Void> waitForTransactionToComplete(ListenableFuture<Void> future) {
         try {
-            futures.get();
+            future.get();
         } catch (InterruptedException | ExecutionException e) {
-            // NETVIRT-1215: Do not log.error() here, only debug()
+            // NETVIRT-1215: Do not log.error() here, only debug(); but callers *MUST* @CheckReturnValue
             LOG.debug("Error writing to datastore", e);
         }
-        return futures;
+        return future;
     }
 
     public static boolean isVxlan(@Nullable ElanInstance elanInstance) {
@@ -1398,7 +1377,7 @@ public class ElanUtils {
                 && elanInstance.getSegmentationId() != null && elanInstance.getSegmentationId() != 0;
     }
 
-    private static boolean isVxlanSegment(ElanInstance elanInstance) {
+    private static boolean isVxlanSegment(@Nullable ElanInstance elanInstance) {
         if (elanInstance != null) {
             List<ElanSegments> elanSegments = elanInstance.getElanSegments();
             if (elanSegments != null) {
@@ -1414,7 +1393,7 @@ public class ElanUtils {
         return false;
     }
 
-    public static boolean isVxlanNetworkOrVxlanSegment(ElanInstance elanInstance) {
+    public static boolean isVxlanNetworkOrVxlanSegment(@Nullable ElanInstance elanInstance) {
         return isVxlan(elanInstance) || isVxlanSegment(elanInstance);
     }
 
@@ -1454,18 +1433,21 @@ public class ElanUtils {
     public void addDmacRedirectToDispatcherFlows(Long elanTag, String displayName,
             String macAddress, List<BigInteger> dpnIds) {
         for (BigInteger dpId : dpnIds) {
-            ListenableFutures.addErrorLogging(txRunner.callWithNewWriteOnlyTransactionAndSubmit(
-                tx -> mdsalManager.addFlowToTx(
-                        buildDmacRedirectToDispatcherFlow(dpId, macAddress, displayName, elanTag), tx)), LOG,
+            LoggingFutures.addErrorLogging(txRunner.callWithNewWriteOnlyTransactionAndSubmit(CONFIGURATION,
+                tx -> mdsalManager.addFlow(tx, buildDmacRedirectToDispatcherFlow(dpId, macAddress, displayName,
+                        elanTag))), LOG,
                 "Error adding DMAC redirect to dispatcher flows");
         }
     }
 
     public void removeDmacRedirectToDispatcherFlows(Long elanTag, String macAddress, List<BigInteger> dpnIds) {
-        for (BigInteger dpId : dpnIds) {
-            String flowId = getKnownDynamicmacFlowRef(NwConstants.ELAN_DMAC_TABLE, dpId, macAddress, elanTag);
-            mdsalManager.removeFlow(dpId, MDSALUtil.buildFlow(NwConstants.ELAN_DMAC_TABLE, flowId));
-        }
+        LoggingFutures.addErrorLogging(
+            txRunner.callWithNewReadWriteTransactionAndSubmit(Datastore.CONFIGURATION, tx -> {
+                for (BigInteger dpId : dpnIds) {
+                    String flowId = getKnownDynamicmacFlowRef(NwConstants.ELAN_DMAC_TABLE, dpId, macAddress, elanTag);
+                    mdsalManager.removeFlow(tx, dpId, MDSALUtil.buildFlow(NwConstants.ELAN_DMAC_TABLE, flowId));
+                }
+            }), LOG, "Error removing DMAC redirect to dispatcher flows");
     }
 
     public static FlowEntity buildDmacRedirectToDispatcherFlow(BigInteger dpId, String dstMacAddress,
@@ -1484,6 +1466,7 @@ public class ElanUtils {
                 matches, instructions);
     }
 
+    @Nullable
     public String getExternalElanInterface(String elanInstanceName, BigInteger dpnId) {
         DpnInterfaces dpnInterfaces = getElanInterfaceInfoByElanDpn(elanInstanceName, dpnId);
         if (dpnInterfaces == null || dpnInterfaces.getInterfaces() == null) {
@@ -1501,14 +1484,8 @@ public class ElanUtils {
         return null;
     }
 
-    public static String getElanMacDPNKey(long elanTag, String macAddress, BigInteger dpnId) {
-        String elanMacDmacDpnKey = "MAC-" + macAddress + " ELAN_TAG-" + elanTag + "DPN_ID-" + dpnId;
-        return elanMacDmacDpnKey.intern();
-    }
-
-    public static String getElanMacKey(long elanTag, String macAddress) {
-        String elanMacKey = "MAC-" + macAddress + " ELAN_TAG-" + elanTag;
-        return elanMacKey.intern();
+    public static Acquired lockElanMacDPN(long elanTag, String macAddress, BigInteger dpnId) {
+        return ELAN_LOCKS.acquire(new ElanLockName(elanTag, macAddress, dpnId));
     }
 
     public static List<ListenableFuture<Void>>
@@ -1551,18 +1528,6 @@ public class ElanUtils {
                         new StaticMacEntriesKey(new PhysAddress(macAddress))).build();
     }
 
-    public static List<StaticMacEntries> getDeletedEntries(List<StaticMacEntries> originalStaticMacEntries,
-                                                           List<StaticMacEntries> updatedStaticMacEntries) {
-        if (isEmpty(originalStaticMacEntries)) {
-            return Collections.EMPTY_LIST;
-        }
-        List<StaticMacEntries> deleted = Lists.newArrayList(originalStaticMacEntries);
-        if (isNotEmpty(updatedStaticMacEntries)) {
-            deleted.removeAll(updatedStaticMacEntries);
-        }
-        return deleted;
-    }
-
     public static <T> List<T> diffOf(List<T> orig, List<T> updated) {
         if (isEmpty(orig)) {
             return Collections.EMPTY_LIST;
@@ -1574,18 +1539,6 @@ public class ElanUtils {
         return diff;
     }
 
-    public static void segregateToBeDeletedAndAddEntries(List<StaticMacEntries> originalStaticMacEntries,
-                                                             List<StaticMacEntries> updatedStaticMacEntries) {
-        if (isNotEmpty(updatedStaticMacEntries)) {
-            List<StaticMacEntries> existingClonedStaticMacEntries = new ArrayList<>();
-            if (isNotEmpty(originalStaticMacEntries)) {
-                existingClonedStaticMacEntries.addAll(0, originalStaticMacEntries);
-                originalStaticMacEntries.removeAll(updatedStaticMacEntries);
-                updatedStaticMacEntries.removeAll(existingClonedStaticMacEntries);
-            }
-        }
-    }
-
     public static boolean isEmpty(Collection collection) {
         return collection == null || collection.isEmpty();
     }
@@ -1616,7 +1569,7 @@ public class ElanUtils {
     public List<MacEntry> getElanMacEntries(String elanName) {
         MacTable macTable = getElanMacTable(elanName);
         if (macTable == null) {
-            return Collections.emptyList();
+            return emptyList();
         }
         return macTable.getMacEntry();
     }
@@ -1625,12 +1578,16 @@ public class ElanUtils {
         org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang
             .ietf.interfaces.rev140508.interfaces.Interface configIface =
             interfaceManager.getInterfaceInfoFromConfigDataStore(interfaceName);
-        IfTunnel ifTunnel = configIface.getAugmentation(IfTunnel.class);
+        if (configIface == null) {
+            configIface = iitmProvider.getInterface(interfaceName);
+        }
+        if (configIface == null) {
+            return  false;
+        }
+        IfTunnel ifTunnel = configIface.augmentation(IfTunnel.class);
         if (ifTunnel != null && ifTunnel.getTunnelInterfaceType().isAssignableFrom(TunnelTypeVxlan.class)) {
-            ParentRefs refs = configIface.getAugmentation(ParentRefs.class);
-            if (refs != null && !Strings.isNullOrEmpty(refs.getParentInterface())) {
-                return true; //multiple VxLAN tunnels enabled, i.e. only logical tunnel should be treated
-            }
+            ParentRefs refs = configIface.augmentation(ParentRefs.class);
+            return refs != null && !Strings.isNullOrEmpty(refs.getParentInterface());
         }
         return false;
     }
@@ -1640,10 +1597,10 @@ public class ElanUtils {
         org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId nodeId =
                 new org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId("openflow:" + dpnId);
         org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node nodeDpn =
-                new NodeBuilder().setId(nodeId).setKey(new NodeKey(nodeId)).build();
+                new NodeBuilder().setId(nodeId).withKey(new NodeKey(nodeId)).build();
         return InstanceIdentifier.builder(Nodes.class)
                 .child(org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node.class,
-                        nodeDpn.getKey()).augmentation(FlowCapableNode.class)
+                        nodeDpn.key()).augmentation(FlowCapableNode.class)
                 .child(Table.class, new TableKey(flow.getTableId())).child(Flow.class, flowKey).build();
     }
 
@@ -1655,9 +1612,12 @@ public class ElanUtils {
             int lportTag) {
         LOG.info("Removing the ARP responder flow on DPN {} of Interface {} with IP {}", dpnId, ingressInterfaceName,
                 ipAddress);
-        ArpResponderUtil.removeFlow(mdsalManager, dpnId, ArpResponderUtil.getFlowId(lportTag, ipAddress));
+        LoggingFutures.addErrorLogging(txRunner.callWithNewReadWriteTransactionAndSubmit(Datastore.CONFIGURATION,
+            tx -> mdsalManager.removeFlow(tx, dpnId, ArpResponderUtil.getFlowId(lportTag, ipAddress),
+                NwConstants.ARP_RESPONDER_TABLE)), LOG, "Error removing ARP responder flow");
     }
 
+    @Nullable
     public static String getRouterPordIdFromElanInstance(DataBroker dataBroker, String elanInstanceName) {
         Optional<Subnetmaps> subnetMapsData =
                 read(dataBroker, LogicalDatastoreType.CONFIGURATION, buildSubnetMapsWildCardPath());
@@ -1679,6 +1639,9 @@ public class ElanUtils {
     static InstanceIdentifier<Subnetmaps> buildSubnetMapsWildCardPath() {
         return InstanceIdentifier.create(Subnetmaps.class);
     }
-}
-
 
+    public static InstanceIdentifier<Group> getGroupInstanceid(BigInteger dpnId, long groupId) {
+        return InstanceIdentifier.builder(Nodes.class).child(Node.class, new NodeKey(new NodeId("openflow:" + dpnId)))
+                .augmentation(FlowCapableNode.class).child(Group.class, new GroupKey(new GroupId(groupId))).build();
+    }
+}