Merge branch 'master' of ssh://gerrit.onlab.us:29418/onos-next

@@ -56,6 +56,13 @@ public interface MastershipService {
     Set<DeviceId> getDevicesOf(NodeId nodeId);
 
     /**
+     * Returns the mastership term service for getting term information.
+     *
+     * @return the MastershipTermService for this mastership manager
+     */
+    MastershipTermService requestTermService();
+
+    /**
      * Adds the specified mastership change listener.
      *
      * @param listener the mastership listener

@@ -55,4 +55,13 @@ public interface MastershipStore extends Store<MastershipEvent, MastershipStoreD
      * @return a mastership event
      */
     MastershipEvent setMaster(NodeId nodeId, DeviceId deviceId);
+
+    /**
+     * Returns the current master and number of past mastership hand-offs
+     * (terms) for a device.
+     *
+     * @param deviceId the device identifier
+     * @return the current master's ID and the term value for device, or null
+     */
+    MastershipTerm getTermFor(DeviceId deviceId);
 }

 package org.onlab.onos.cluster;
 
-public class MastershipTerm {
-    private final NodeId master = null;
+import java.util.Objects;
+
+public final class MastershipTerm {
+
+    private final NodeId master;
     private int termNumber;
+
+    private MastershipTerm(NodeId master, int term) {
+        this.master = master;
+        this.termNumber = term;
+    }
+
+    public static MastershipTerm of(NodeId master, int term) {
+        return new MastershipTerm(master, term);
+    }
+
+    public NodeId master() {
+        return master;
+    }
+
+    public int termNumber() {
+        return termNumber;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(master, termNumber);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (this == other) {
+            return true;
+        }
+        if (other instanceof MastershipTerm) {
+            MastershipTerm that = (MastershipTerm) other;
+            if (!this.master.equals(that.master)) {
+                return false;
+            }
+            if (this.termNumber != that.termNumber) {
+                return false;
+            }
+            return true;
+        }
+        return false;
+    }
 }

+package org.onlab.onos.net;
+
+import java.util.Objects;
+
+import com.google.common.base.MoreObjects;
+
+// TODO Consider renaming.
+// it's an identifier for a Link, but it's not ElementId, so not using LinkId.
+/**
+ * Immutable representation of a link identity.
+ */
+public class LinkKey {
+
+    private final ConnectPoint src;
+    private final ConnectPoint dst;
+
+    /**
+     * Returns source connection point.
+     *
+     * @return source connection point
+     */
+    public ConnectPoint src() {
+        return src;
+    }
+
+    /**
+     * Returns destination connection point.
+     *
+     * @return destination connection point
+     */
+    public ConnectPoint dst() {
+        return dst;
+    }
+
+    /**
+     * Creates a link identifier with source and destination connection point.
+     *
+     * @param src source connection point
+     * @param dst destination connection point
+     */
+    public LinkKey(ConnectPoint src, ConnectPoint dst) {
+        this.src = src;
+        this.dst = dst;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(src(), dst);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof LinkKey) {
+            final LinkKey other = (LinkKey) obj;
+            return Objects.equals(this.src(), other.src()) &&
+                    Objects.equals(this.dst, other.dst);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("src", src())
+                .add("dst", dst)
+                .toString();
+    }
+}

@@ -40,4 +40,9 @@ public class MastershipServiceAdapter implements MastershipService {
     @Override
     public void removeListener(MastershipListener listener) {
     }
+
+    @Override
+    public MastershipTermService requestTermService() {
+        return null;
+    }
 }

@@ -12,6 +12,8 @@ import org.onlab.onos.cluster.MastershipEvent;
 import org.onlab.onos.cluster.MastershipListener;
 import org.onlab.onos.cluster.MastershipService;
 import org.onlab.onos.cluster.MastershipStore;
+import org.onlab.onos.cluster.MastershipTerm;
+import org.onlab.onos.cluster.MastershipTermService;
 import org.onlab.onos.cluster.NodeId;
 import org.onlab.onos.event.AbstractListenerRegistry;
 import org.onlab.onos.event.EventDeliveryService;
@@ -103,6 +105,12 @@ public class MastershipManager
         return store.getDevices(nodeId);
     }
 
+
+    @Override
+    public MastershipTermService requestTermService() {
+        return new InternalMastershipTermService();
+    }
+
     @Override
     public void addListener(MastershipListener listener) {
         checkNotNull(listener);
@@ -124,4 +132,13 @@ public class MastershipManager
         }
     }
 
+    private class InternalMastershipTermService implements MastershipTermService {
+
+        @Override
+        public MastershipTerm getMastershipTerm(DeviceId deviceId) {
+            return store.getTermFor(deviceId);
+        }
+
+    }
+
 }

@@ -11,6 +11,7 @@ import org.onlab.onos.cluster.ControllerNode;
 import org.onlab.onos.cluster.ControllerNode.State;
 import org.onlab.onos.cluster.DefaultControllerNode;
 import org.onlab.onos.cluster.MastershipService;
+import org.onlab.onos.cluster.MastershipTermService;
 import org.onlab.onos.cluster.NodeId;
 import org.onlab.onos.event.impl.TestEventDispatcher;
 import org.onlab.onos.net.DeviceId;
@@ -100,6 +101,20 @@ public class MastershipManagerTest {
         assertEquals("should be two devices:", 2, mgr.getDevicesOf(NID_LOCAL).size());
     }
 
+    @Test
+    public void termService() {
+        MastershipTermService ts = mgr.requestTermService();
+
+        //term = 0 for both
+        mgr.setRole(NID_LOCAL, DEV_MASTER, MASTER);
+        assertEquals("inconsistent term: ", 0, ts.getMastershipTerm(DEV_MASTER).termNumber());
+
+        //hand devices to NID_LOCAL and back: term = 2
+        mgr.setRole(NID_OTHER, DEV_MASTER, MASTER);
+        mgr.setRole(NID_LOCAL, DEV_MASTER, MASTER);
+        assertEquals("inconsistent terms: ", 2, ts.getMastershipTerm(DEV_MASTER).termNumber());
+    }
+
     private final class TestClusterService implements ClusterService {
 
         ControllerNode local = new DefaultControllerNode(NID_LOCAL, LOCALHOST);

@@ -15,6 +15,7 @@ import org.onlab.onos.cluster.ClusterService;
 import org.onlab.onos.cluster.MastershipEvent;
 import org.onlab.onos.cluster.MastershipStore;
 import org.onlab.onos.cluster.MastershipStoreDelegate;
+import org.onlab.onos.cluster.MastershipTerm;
 import org.onlab.onos.cluster.NodeId;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.MastershipRole;
@@ -115,4 +116,10 @@ public class DistributedMastershipStore
         return nodeId.equals(master) ? MastershipRole.MASTER : MastershipRole.STANDBY;
     }
 
+    @Override
+    public MastershipTerm getTermFor(DeviceId deviceId) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
 }

@@ -369,7 +369,7 @@ public class DistributedDeviceStore
         }
 
         @Override
-        protected void onUpdate(DeviceId deviceId, DefaultDevice device) {
+        protected void onUpdate(DeviceId deviceId, DefaultDevice oldDevice, DefaultDevice device) {
             notifyDelegate(new DeviceEvent(DEVICE_UPDATED, device));
         }
     }
@@ -390,7 +390,7 @@ public class DistributedDeviceStore
         }
 
         @Override
-        protected void onUpdate(DeviceId deviceId, Map<PortNumber, Port> ports) {
+        protected void onUpdate(DeviceId deviceId, Map<PortNumber, Port> oldPorts, Map<PortNumber, Port> ports) {
 //            notifyDelegate(new DeviceEvent(PORT_UPDATED, getDevice(deviceId)));
         }
     }

@@ -101,7 +101,7 @@ public abstract class AbstractDistributedStore<E extends Event, D extends StoreD
             V newVal = deserialize(event.getValue());
             Optional<V> newValue = Optional.of(newVal);
             cache.asMap().replace(key, oldValue, newValue);
-            onUpdate(key, newVal);
+            onUpdate(key, oldVal, newVal);
         }
 
         @Override
@@ -125,9 +125,10 @@ public abstract class AbstractDistributedStore<E extends Event, D extends StoreD
          * Cache entry update hook.
          *
          * @param key    new key
+         * @param oldValue old value
          * @param newVal new value
          */
-        protected void onUpdate(K key, V newVal) {
+        protected void onUpdate(K key, V oldValue, V newVal) {
         }
 
         /**

@@ -14,19 +14,26 @@ import org.apache.felix.scr.annotations.Service;
 import org.onlab.onos.cluster.ControllerNode;
 import org.onlab.onos.cluster.DefaultControllerNode;
 import org.onlab.onos.cluster.NodeId;
+import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.DefaultDevice;
+import org.onlab.onos.net.DefaultLink;
 import org.onlab.onos.net.DefaultPort;
 import org.onlab.onos.net.Device;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.Element;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.LinkKey;
 import org.onlab.onos.net.MastershipRole;
 import org.onlab.onos.net.Port;
 import org.onlab.onos.net.PortNumber;
 import org.onlab.onos.net.provider.ProviderId;
 import org.onlab.onos.store.common.StoreService;
+import org.onlab.onos.store.serializers.ConnectPointSerializer;
+import org.onlab.onos.store.serializers.DefaultLinkSerializer;
 import org.onlab.onos.store.serializers.DefaultPortSerializer;
 import org.onlab.onos.store.serializers.DeviceIdSerializer;
 import org.onlab.onos.store.serializers.IpPrefixSerializer;
+import org.onlab.onos.store.serializers.LinkKeySerializer;
 import org.onlab.onos.store.serializers.NodeIdSerializer;
 import org.onlab.onos.store.serializers.OnosTimestampSerializer;
 import org.onlab.onos.store.serializers.PortNumberSerializer;
@@ -84,7 +91,9 @@ public class StoreManager implements StoreService {
                           DefaultDevice.class,
                           MastershipRole.class,
                           Port.class,
-                          Element.class
+                          Element.class,
+
+                          Link.Type.class
                 )
                 .register(IpPrefix.class, new IpPrefixSerializer())
                 .register(URI.class, new URISerializer())
@@ -94,6 +103,9 @@ public class StoreManager implements StoreService {
                 .register(PortNumber.class, new PortNumberSerializer())
                 .register(DefaultPort.class, new DefaultPortSerializer())
                 .register(OnosTimestamp.class, new OnosTimestampSerializer())
+                .register(LinkKey.class, new LinkKeySerializer())
+                .register(ConnectPoint.class, new ConnectPointSerializer())
+                .register(DefaultLink.class, new DefaultLinkSerializer())
                 .build()
                 .populate(10);
     }

+package org.onlab.onos.store.link.impl;
+
+import static com.google.common.cache.CacheBuilder.newBuilder;
+import static org.onlab.onos.net.Link.Type.DIRECT;
+import static org.onlab.onos.net.Link.Type.INDIRECT;
+import static org.onlab.onos.net.link.LinkEvent.Type.LINK_ADDED;
+import static org.onlab.onos.net.link.LinkEvent.Type.LINK_REMOVED;
+import static org.onlab.onos.net.link.LinkEvent.Type.LINK_UPDATED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+import java.util.HashSet;
+import java.util.Set;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.DefaultLink;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.LinkKey;
+import org.onlab.onos.net.link.LinkDescription;
+import org.onlab.onos.net.link.LinkEvent;
+import org.onlab.onos.net.link.LinkStore;
+import org.onlab.onos.net.link.LinkStoreDelegate;
+import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.store.impl.AbsentInvalidatingLoadingCache;
+import org.onlab.onos.store.impl.AbstractDistributedStore;
+import org.onlab.onos.store.impl.OptionalCacheLoader;
+import org.slf4j.Logger;
+
+import com.google.common.base.Optional;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.ImmutableSet.Builder;
+import com.hazelcast.core.IMap;
+
+/**
+ * Manages inventory of infrastructure links using Hazelcast-backed map.
+ */
+@Component(immediate = true)
+@Service
+public class DistributedLinkStore
+    extends AbstractDistributedStore<LinkEvent, LinkStoreDelegate>
+    implements LinkStore {
+
+    private final Logger log = getLogger(getClass());
+
+    // Link inventory
+    private IMap<byte[], byte[]> rawLinks;
+    private LoadingCache<LinkKey, Optional<DefaultLink>> links;
+
+    // TODO synchronize?
+    // Egress and ingress link sets
+    private final Multimap<DeviceId, Link> srcLinks = HashMultimap.create();
+    private final Multimap<DeviceId, Link> dstLinks = HashMultimap.create();
+
+    @Override
+    @Activate
+    public void activate() {
+        super.activate();
+
+        boolean includeValue = true;
+
+        // TODO decide on Map name scheme to avoid collision
+        rawLinks = theInstance.getMap("links");
+        final OptionalCacheLoader<LinkKey, DefaultLink> linkLoader
+                = new OptionalCacheLoader<>(storeService, rawLinks);
+        links = new AbsentInvalidatingLoadingCache<>(newBuilder().build(linkLoader));
+        // refresh/populate cache based on notification from other instance
+        rawLinks.addEntryListener(new RemoteLinkEventHandler(links), includeValue);
+
+        loadLinkCache();
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        super.activate();
+        log.info("Stopped");
+    }
+
+    private void loadLinkCache() {
+        for (byte[] keyBytes : rawLinks.keySet()) {
+            final LinkKey id = deserialize(keyBytes);
+            links.refresh(id);
+        }
+    }
+
+    @Override
+    public int getLinkCount() {
+        return links.asMap().size();
+    }
+
+    @Override
+    public Iterable<Link> getLinks() {
+        Builder<Link> builder = ImmutableSet.builder();
+        for (Optional<DefaultLink> e : links.asMap().values()) {
+            if (e.isPresent()) {
+                builder.add(e.get());
+            }
+        }
+        return builder.build();
+    }
+
+    @Override
+    public Set<Link> getDeviceEgressLinks(DeviceId deviceId) {
+        return ImmutableSet.copyOf(srcLinks.get(deviceId));
+    }
+
+    @Override
+    public Set<Link> getDeviceIngressLinks(DeviceId deviceId) {
+        return ImmutableSet.copyOf(dstLinks.get(deviceId));
+    }
+
+    @Override
+    public Link getLink(ConnectPoint src, ConnectPoint dst) {
+        return links.getUnchecked(new LinkKey(src, dst)).orNull();
+    }
+
+    @Override
+    public Set<Link> getEgressLinks(ConnectPoint src) {
+        Set<Link> egress = new HashSet<>();
+        for (Link link : srcLinks.get(src.deviceId())) {
+            if (link.src().equals(src)) {
+                egress.add(link);
+            }
+        }
+        return egress;
+    }
+
+    @Override
+    public Set<Link> getIngressLinks(ConnectPoint dst) {
+        Set<Link> ingress = new HashSet<>();
+        for (Link link : dstLinks.get(dst.deviceId())) {
+            if (link.dst().equals(dst)) {
+                ingress.add(link);
+            }
+        }
+        return ingress;
+    }
+
+    @Override
+    public LinkEvent createOrUpdateLink(ProviderId providerId,
+                                        LinkDescription linkDescription) {
+        LinkKey key = new LinkKey(linkDescription.src(), linkDescription.dst());
+        Optional<DefaultLink> link = links.getUnchecked(key);
+        if (!link.isPresent()) {
+            return createLink(providerId, key, linkDescription);
+        }
+        return updateLink(providerId, link.get(), key, linkDescription);
+    }
+
+    // Creates and stores the link and returns the appropriate event.
+    private LinkEvent createLink(ProviderId providerId, LinkKey key,
+                                 LinkDescription linkDescription) {
+        DefaultLink link = new DefaultLink(providerId, key.src(), key.dst(),
+                                           linkDescription.type());
+        synchronized (this) {
+            final byte[] keyBytes = serialize(key);
+            rawLinks.put(keyBytes, serialize(link));
+            links.asMap().putIfAbsent(key, Optional.of(link));
+
+            addNewLink(link);
+        }
+        return new LinkEvent(LINK_ADDED, link);
+    }
+
+    // update Egress and ingress link sets
+    private void addNewLink(DefaultLink link) {
+        synchronized (this) {
+            srcLinks.put(link.src().deviceId(), link);
+            dstLinks.put(link.dst().deviceId(), link);
+        }
+    }
+
+    // Updates, if necessary the specified link and returns the appropriate event.
+    private LinkEvent updateLink(ProviderId providerId, DefaultLink link,
+                                 LinkKey key, LinkDescription linkDescription) {
+        // FIXME confirm Link update condition is OK
+        if (link.type() == INDIRECT && linkDescription.type() == DIRECT) {
+            synchronized (this) {
+
+                DefaultLink updated =
+                        new DefaultLink(providerId, link.src(), link.dst(),
+                                        linkDescription.type());
+                final byte[] keyBytes = serialize(key);
+                rawLinks.put(keyBytes, serialize(updated));
+                links.asMap().replace(key, Optional.of(link), Optional.of(updated));
+
+                replaceLink(link, updated);
+                return new LinkEvent(LINK_UPDATED, updated);
+            }
+        }
+        return null;
+    }
+
+    // update Egress and ingress link sets
+    private void replaceLink(DefaultLink link, DefaultLink updated) {
+        synchronized (this) {
+            srcLinks.remove(link.src().deviceId(), link);
+            dstLinks.remove(link.dst().deviceId(), link);
+
+            srcLinks.put(link.src().deviceId(), updated);
+            dstLinks.put(link.dst().deviceId(), updated);
+        }
+    }
+
+    @Override
+    public LinkEvent removeLink(ConnectPoint src, ConnectPoint dst) {
+        synchronized (this) {
+            LinkKey key = new LinkKey(src, dst);
+            byte[] keyBytes = serialize(key);
+            Link link = deserialize(rawLinks.remove(keyBytes));
+            links.invalidate(key);
+            if (link != null) {
+                removeLink(link);
+                return new LinkEvent(LINK_REMOVED, link);
+            }
+            return null;
+        }
+    }
+
+    // update Egress and ingress link sets
+    private void removeLink(Link link) {
+        synchronized (this) {
+            srcLinks.remove(link.src().deviceId(), link);
+            dstLinks.remove(link.dst().deviceId(), link);
+        }
+    }
+
+    private class RemoteLinkEventHandler extends RemoteEventHandler<LinkKey, DefaultLink> {
+        public RemoteLinkEventHandler(LoadingCache<LinkKey, Optional<DefaultLink>> cache) {
+            super(cache);
+        }
+
+        @Override
+        protected void onAdd(LinkKey key, DefaultLink newVal) {
+            addNewLink(newVal);
+            notifyDelegate(new LinkEvent(LINK_ADDED, newVal));
+        }
+
+        @Override
+        protected void onUpdate(LinkKey key, DefaultLink oldVal, DefaultLink newVal) {
+            replaceLink(oldVal, newVal);
+            notifyDelegate(new LinkEvent(LINK_UPDATED, newVal));
+        }
+
+        @Override
+        protected void onRemove(LinkKey key, DefaultLink val) {
+            removeLink(val);
+            notifyDelegate(new LinkEvent(LINK_REMOVED, val));
+        }
+    }
+}

+/**
+ * Implementation of link store using Hazelcast distributed structures.
+ */
+package org.onlab.onos.store.link.impl;

+package org.onlab.onos.store.serializers;
+
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.ElementId;
+import org.onlab.onos.net.PortNumber;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+/**
+ * Kryo Serializer for {@link ConnectPointSerializer}.
+ */
+public class ConnectPointSerializer extends Serializer<ConnectPoint> {
+
+    /**
+     * Default constructor.
+     */
+    public ConnectPointSerializer() {
+        // non-null, immutable
+        super(false, true);
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output, ConnectPoint object) {
+        kryo.writeClassAndObject(output, object.elementId());
+        kryo.writeClassAndObject(output, object.port());
+    }
+
+    @Override
+    public ConnectPoint read(Kryo kryo, Input input, Class<ConnectPoint> type) {
+        ElementId elementId = (ElementId) kryo.readClassAndObject(input);
+        PortNumber portNumber = (PortNumber) kryo.readClassAndObject(input);
+        return new ConnectPoint(elementId, portNumber);
+    }
+}

+package org.onlab.onos.store.serializers;
+
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.DefaultLink;
+import org.onlab.onos.net.Link.Type;
+import org.onlab.onos.net.provider.ProviderId;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+/**
+ * Kryo Serializer for {@link DefaultLink}.
+ */
+public class DefaultLinkSerializer extends Serializer<DefaultLink> {
+
+    /**
+     * Default constructor.
+     */
+    public DefaultLinkSerializer() {
+        // non-null, immutable
+        super(false, true);
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output, DefaultLink object) {
+        kryo.writeClassAndObject(output, object.providerId());
+        kryo.writeClassAndObject(output, object.src());
+        kryo.writeClassAndObject(output, object.dst());
+        kryo.writeClassAndObject(output, object.type());
+    }
+
+    @Override
+    public DefaultLink read(Kryo kryo, Input input, Class<DefaultLink> type) {
+        ProviderId providerId = (ProviderId) kryo.readClassAndObject(input);
+        ConnectPoint src = (ConnectPoint) kryo.readClassAndObject(input);
+        ConnectPoint dst = (ConnectPoint) kryo.readClassAndObject(input);
+        Type linkType = (Type) kryo.readClassAndObject(input);
+        return new DefaultLink(providerId, src, dst, linkType);
+    }
+}

+package org.onlab.onos.store.serializers;
+
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.LinkKey;
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+/**
+ * Kryo Serializer for {@link LinkKey}.
+ */
+public class LinkKeySerializer extends Serializer<LinkKey> {
+
+    /**
+     * Default constructor.
+     */
+    public LinkKeySerializer() {
+        // non-null, immutable
+        super(false, true);
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output, LinkKey object) {
+        kryo.writeClassAndObject(output, object.src());
+        kryo.writeClassAndObject(output, object.dst());
+    }
+
+    @Override
+    public LinkKey read(Kryo kryo, Input input, Class<LinkKey> type) {
+        ConnectPoint src = (ConnectPoint) kryo.readClassAndObject(input);
+        ConnectPoint dst = (ConnectPoint) kryo.readClassAndObject(input);
+        return new LinkKey(src, dst);
+    }
+}

@@ -3,6 +3,7 @@ package org.onlab.onos.net.trivial.impl;
 import com.google.common.collect.HashMultimap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Multimap;
+
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -11,6 +12,7 @@ import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.DefaultLink;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.Link;
+import org.onlab.onos.net.LinkKey;
 import org.onlab.onos.net.link.LinkDescription;
 import org.onlab.onos.net.link.LinkEvent;
 import org.onlab.onos.net.link.LinkStore;
@@ -22,7 +24,6 @@ import org.slf4j.Logger;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -123,7 +124,7 @@ public class SimpleLinkStore
     // Creates and stores the link and returns the appropriate event.
     private LinkEvent createLink(ProviderId providerId, LinkKey key,
                                  LinkDescription linkDescription) {
-        DefaultLink link = new DefaultLink(providerId, key.src, key.dst,
+        DefaultLink link = new DefaultLink(providerId, key.src(), key.dst(),
                                            linkDescription.type());
         synchronized (this) {
             links.put(key, link);
@@ -165,33 +166,4 @@ public class SimpleLinkStore
             return null;
         }
     }
-
-    // Auxiliary key to track links.
-    private class LinkKey {
-        final ConnectPoint src;
-        final ConnectPoint dst;
-
-        LinkKey(ConnectPoint src, ConnectPoint dst) {
-            this.src = src;
-            this.dst = dst;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(src, dst);
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            if (this == obj) {
-                return true;
-            }
-            if (obj instanceof LinkKey) {
-                final LinkKey other = (LinkKey) obj;
-                return Objects.equals(this.src, other.src) &&
-                        Objects.equals(this.dst, other.dst);
-            }
-            return false;
-        }
-    }
 }

@@ -3,11 +3,13 @@ package org.onlab.onos.net.trivial.impl;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -18,6 +20,7 @@ import org.onlab.onos.cluster.DefaultControllerNode;
 import org.onlab.onos.cluster.MastershipEvent;
 import org.onlab.onos.cluster.MastershipStore;
 import org.onlab.onos.cluster.MastershipStoreDelegate;
+import org.onlab.onos.cluster.MastershipTerm;
 import org.onlab.onos.cluster.NodeId;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.MastershipRole;
@@ -47,6 +50,7 @@ public class SimpleMastershipStore
     //devices mapped to their masters, to emulate multiple nodes
     protected final ConcurrentMap<DeviceId, NodeId> masterMap =
             new ConcurrentHashMap<>();
+    protected final Map<DeviceId, AtomicInteger> termMap = new HashMap<>();
 
     @Activate
     public void activate() {
@@ -63,15 +67,21 @@ public class SimpleMastershipStore
 
         NodeId node = masterMap.get(deviceId);
         if (node == null) {
-            masterMap.put(deviceId, nodeId);
+            synchronized (this) {
+                masterMap.put(deviceId, nodeId);
+                termMap.put(deviceId, new AtomicInteger());
+            }
             return new MastershipEvent(MASTER_CHANGED, deviceId, nodeId);
         }
 
         if (node.equals(nodeId)) {
             return null;
         } else {
-            masterMap.put(deviceId, nodeId);
-            return new MastershipEvent(MASTER_CHANGED, deviceId, nodeId);
+            synchronized (this) {
+                masterMap.put(deviceId, nodeId);
+                termMap.get(deviceId).incrementAndGet();
+                return new MastershipEvent(MASTER_CHANGED, deviceId, nodeId);
+            }
         }
     }
 
@@ -114,4 +124,13 @@ public class SimpleMastershipStore
         return role;
     }
 
+    @Override
+    public MastershipTerm getTermFor(DeviceId deviceId) {
+        if (masterMap.get(deviceId) == null) {
+            return null;
+        }
+        return MastershipTerm.of(
+                masterMap.get(deviceId), termMap.get(deviceId).get());
+    }
+
 }