Refactored Kafka Application to simplify dependencies

1. Fixed a Bug in KafkaProducer. Without this fix the App will not send data in GPB format.
2. Added two new services - KafkaProducerService and KafkaConfigService.
3. Fixed a TODO in the register API to return Kafka server information.
4. Removed the use of LeadershipService and ClusterService, since we are not ready for clustering yet.

Change-Id: If20ef5238bb4629af0c6769129494eb44abf1d3c

@@ -39,6 +39,12 @@
             <version>3.0.0-beta-2</version>
         </dependency>
 
+        <dependency>
+            <groupId>org.apache.servicemix.bundles</groupId>
+            <artifactId>org.apache.servicemix.bundles.kafka-clients</artifactId>
+            <version>0.8.2.2_1</version>
+        </dependency>
+
     </dependencies>
 
     <build>

@@ -14,16 +14,16 @@
  */
 package org.onosproject.kafkaintegration.api;
 
+import java.util.List;
+
 import org.onosproject.kafkaintegration.api.dto.EventSubscriber;
-import org.onosproject.kafkaintegration.api.dto.EventSubscriberGroupId;
 import org.onosproject.kafkaintegration.api.dto.OnosEvent.Type;
+import org.onosproject.kafkaintegration.api.dto.RegistrationResponse;
 import org.onosproject.kafkaintegration.errors.InvalidApplicationException;
 import org.onosproject.kafkaintegration.errors.InvalidGroupIdException;
 
 import com.google.common.annotations.Beta;
 
-import java.util.List;
-
 /**
  * APIs for subscribing to Onos Event Messages.
  */
@@ -34,9 +34,9 @@ public interface EventSubscriptionService {
      * Registers the external application to receive events generated in ONOS.
      *
      * @param appName Application Name
-     * @return unique consumer group identifier
+     * @return Registration Response DTO.
      */
-    EventSubscriberGroupId registerListener(String appName);
+    RegistrationResponse registerListener(String appName);
 
     /**
      * Removes the Registered Listener.

+/**
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.kafkaintegration.api;
+
+import org.onosproject.kafkaintegration.api.dto.KafkaServerConfig;
+
+public interface KafkaConfigService {
+
+    /**
+     * Returns the Kafka Server Configuration Information.
+     *
+     * @return KafkaServerConfig DTO Object.
+     */
+    KafkaServerConfig getConfigParams();
+
+}
+

+/**
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.kafkaintegration.api;
+
+import java.util.concurrent.Future;
+
+import org.onosproject.kafkaintegration.api.dto.KafkaServerConfig;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.clients.producer.RecordMetadata;
+/**
+ * APIs for controlling the Kafka Producer.
+ *
+ */
+public interface KafkaProducerService {
+
+    /**
+     * Starts the Kafka Producer.
+     *
+     * @param config the Kafka Server Config
+     */
+    void start(KafkaServerConfig config);
+
+    /**
+     * Stops the Kafka Producer.
+     *
+     */
+    void stop();
+
+    /**
+     * Restarts the Kafka Producer.
+     *
+     * @param config the Kafka Server Config
+     */
+    void restart(KafkaServerConfig config);
+
+    /**
+     * Sends message to Kafka Server.
+     *
+     * @param record a message to be sent
+     * @return metadata for a record that as been acknowledged
+     */
+    public Future<RecordMetadata> send(ProducerRecord<String, byte[]> record);
+}

@@ -84,6 +84,7 @@ public final class DefaultEventSubscriber implements EventSubscriber {
                 .addValue(subscriberGroupId.toString())
                 .add("eventType", eventType).toString();
     }
+
     /**
      * To create an instance of the builder.
      *
@@ -92,6 +93,7 @@ public final class DefaultEventSubscriber implements EventSubscriber {
     public static Builder builder() {
         return new Builder();
     }
+
     /**
      * Builder class for Event subscriber.
      */
@@ -107,8 +109,7 @@ public final class DefaultEventSubscriber implements EventSubscriber {
         }
 
         @Override
-        public Builder setSubscriberGroupId(EventSubscriberGroupId
-                                                            subscriberGroupId) {
+        public Builder setSubscriberGroupId(EventSubscriberGroupId subscriberGroupId) {
             this.subscriberGroupId = subscriberGroupId;
             return this;
         }
@@ -122,13 +123,11 @@ public final class DefaultEventSubscriber implements EventSubscriber {
         @Override
         public EventSubscriber build() {
             checkNotNull(appName, "App name cannot be null");
-            checkNotNull(subscriberGroupId, "Subscriber group ID cannot " +
-                    "be " +
-                    "null");
+            checkNotNull(subscriberGroupId,
+                         "Subscriber group ID cannot " + "be " + "null");
             checkNotNull(eventType, "Event type cannot be null");
 
-            return new DefaultEventSubscriber(appName,
-                                              subscriberGroupId,
+            return new DefaultEventSubscriber(appName, subscriberGroupId,
                                               eventType);
         }
     }

+/**
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.kafkaintegration.api.dto;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * DTO to hold Kafka Server Configuration information.
+ *
+ */
+public final class KafkaServerConfig {
+
+    private final String ipAddress;
+
+    private final String port;
+
+    private final int numOfRetries;
+
+    private final int maxInFlightRequestsPerConnection;
+
+    private final int acksRequired;
+
+    private final String keySerializer;
+
+    private final String valueSerializer;
+
+    private KafkaServerConfig(String ipAddress, String port, int numOfRetries,
+                              int maxInFlightRequestsPerConnection,
+                              int requestRequiredAcks, String keySerializer,
+                              String valueSerializer) {
+
+        this.ipAddress = checkNotNull(ipAddress, "Ip Address Cannot be null");
+        this.port = checkNotNull(port, "Port Number cannot be null");
+        this.numOfRetries = numOfRetries;
+        this.maxInFlightRequestsPerConnection =
+                maxInFlightRequestsPerConnection;
+        this.acksRequired = requestRequiredAcks;
+        this.keySerializer = keySerializer;
+        this.valueSerializer = valueSerializer;
+    }
+
+    public final String getIpAddress() {
+        return ipAddress;
+    }
+
+    public final String getPort() {
+        return port;
+    }
+
+    public final int getNumOfRetries() {
+        return numOfRetries;
+    }
+
+    public final int getMaxInFlightRequestsPerConnection() {
+        return maxInFlightRequestsPerConnection;
+    }
+
+    public final int getAcksRequired() {
+        return acksRequired;
+    }
+
+    public final String getKeySerializer() {
+        return keySerializer;
+    }
+
+    public final String getValueSerializer() {
+        return valueSerializer;
+    }
+
+    /**
+     * To create an instance of the builder.
+     *
+     * @return instance of builder
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    /**
+     * Builder class for KafkaServerConfig.
+     */
+    public static final class Builder {
+        private String ipAddress;
+
+        private String port;
+
+        private int numOfRetries;
+
+        private int maxInFlightRequestsPerConnection;
+
+        private int acksRequired;
+
+        private String keySerializer;
+
+        private String valueSerializer;
+
+        public Builder ipAddress(String ipAddress) {
+            this.ipAddress = ipAddress;
+            return this;
+        }
+
+        public Builder port(String port) {
+            this.port = port;
+            return this;
+        }
+
+        public Builder numOfRetries(int numOfRetries) {
+            this.numOfRetries = numOfRetries;
+            return this;
+        }
+
+        public Builder maxInFlightRequestsPerConnection(int maxInFlightRequestsPerConnection) {
+            this.maxInFlightRequestsPerConnection =
+                    maxInFlightRequestsPerConnection;
+            return this;
+        }
+
+        public Builder acksRequired(int acksRequired) {
+            this.acksRequired = acksRequired;
+            return this;
+        }
+
+        public Builder keySerializer(String keySerializer) {
+            this.keySerializer = keySerializer;
+            return this;
+        }
+
+        public Builder valueSerializer(String valueSerializer) {
+            this.valueSerializer = valueSerializer;
+            return this;
+        }
+
+        public KafkaServerConfig build() {
+            checkNotNull(ipAddress, "App name cannot be null");
+            checkNotNull(port, "Subscriber group ID cannot " + "be " + "null");
+
+            return new KafkaServerConfig(ipAddress, port, numOfRetries,
+                                         maxInFlightRequestsPerConnection,
+                                         acksRequired, keySerializer,
+                                         valueSerializer);
+        }
+    }
+}

+/**
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.kafkaintegration.api.dto;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+import java.util.Objects;
+
+/**
+ * DTO to hold Registration Response for requests from external apps.
+ */
+public final class RegistrationResponse {
+
+    private EventSubscriberGroupId groupId;
+
+    private String ipAddress;
+
+    private String port;
+
+    public RegistrationResponse(EventSubscriberGroupId groupId,
+                                String ipAddress, String port) {
+        this.groupId = groupId;
+        this.ipAddress = ipAddress;
+        this.port = port;
+    }
+
+    public final EventSubscriberGroupId getGroupId() {
+        return groupId;
+    }
+
+    public final String getIpAddress() {
+        return ipAddress;
+    }
+
+    public final String getPort() {
+        return port;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o instanceof RegistrationResponse) {
+            RegistrationResponse sub = (RegistrationResponse) o;
+            if (sub.groupId.equals(groupId) && sub.ipAddress.equals(ipAddress)
+                    && sub.port.equals(port)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(groupId, ipAddress, port);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("subscriberGroupId", groupId)
+                .add("ipAddress", ipAddress).add("port", port).toString();
+    }
+}

@@ -30,7 +30,8 @@
     <packaging>bundle</packaging>
     <description>
         Kafka Integration Application.
-        This module is exclusive of REST calls and is only for the implementation of Apache Kafka.
+        This module is exclusive of REST calls and is only for the implementation
+        of the Application.
     </description>
 
     <dependencies>

@@ -15,7 +15,15 @@
  */
 package org.onosproject.kafkaintegration.impl;
 
-import com.google.common.collect.ImmutableList;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.DEVICE;
+import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.LINK;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -25,14 +33,15 @@ import org.apache.felix.scr.annotations.Service;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.CoreService;
 import org.onosproject.kafkaintegration.api.EventSubscriptionService;
+import org.onosproject.kafkaintegration.api.KafkaConfigService;
 import org.onosproject.kafkaintegration.api.dto.DefaultEventSubscriber;
 import org.onosproject.kafkaintegration.api.dto.EventSubscriber;
 import org.onosproject.kafkaintegration.api.dto.EventSubscriberGroupId;
+import org.onosproject.kafkaintegration.api.dto.RegistrationResponse;
 import org.onosproject.kafkaintegration.api.dto.OnosEvent;
 import org.onosproject.kafkaintegration.api.dto.OnosEvent.Type;
 import org.onosproject.kafkaintegration.errors.InvalidApplicationException;
 import org.onosproject.kafkaintegration.errors.InvalidGroupIdException;
-import org.onosproject.kafkaintegration.listener.ListenerFactory;
 import org.onosproject.kafkaintegration.listener.OnosEventListener;
 import org.onosproject.net.device.DeviceService;
 import org.onosproject.net.link.LinkService;
@@ -42,14 +51,7 @@ import org.onosproject.store.service.StorageService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Map;
-import java.util.UUID;
-
-import static com.google.common.base.Preconditions.checkNotNull;
-import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.DEVICE;
-import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.LINK;
+import com.google.common.collect.ImmutableList;
 
 /**
  * Implementation of Event Subscription Manager.
@@ -82,6 +84,9 @@ public class EventSubscriptionManager implements EventSubscriptionService {
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected StorageService storageService;
 
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected KafkaConfigService kafkaConfigService;
+
     private ApplicationId appId;
 
     @Activate
@@ -100,13 +105,11 @@ public class EventSubscriptionManager implements EventSubscriptionService {
         subscriptions = storageService
                 .<Type, List<EventSubscriber>>consistentMapBuilder()
                 .withName(SUBSCRIBED_APPS)
-                .withSerializer(Serializer.using(KryoNamespaces.API,
-                                                 EventSubscriber.class,
-                                                 OnosEvent.class,
-                                                 OnosEvent.Type.class,
+                .withSerializer(Serializer
+                        .using(KryoNamespaces.API, EventSubscriber.class,
+                               OnosEvent.class, OnosEvent.Type.class,
                                DefaultEventSubscriber.class,
-                                                 EventSubscriberGroupId.class,
-                                                 UUID.class))
+                               EventSubscriberGroupId.class, UUID.class))
                 .build().asJavaMap();
 
         log.info("Started");
@@ -118,15 +121,22 @@ public class EventSubscriptionManager implements EventSubscriptionService {
     }
 
     @Override
-    public EventSubscriberGroupId registerListener(String appName) {
+    public RegistrationResponse registerListener(String appName) {
 
         // TODO: Remove it once ONOS provides a mechanism for external apps
         // to register with the core service. See Jira - 4409
         ApplicationId externalAppId = coreService.registerApplication(appName);
 
-        return registeredApps.computeIfAbsent(externalAppId,
+        EventSubscriberGroupId id =
+                registeredApps.computeIfAbsent(externalAppId,
                                                (key) -> new EventSubscriberGroupId(UUID
                                                        .randomUUID()));
+
+        RegistrationResponse response = new RegistrationResponse(id,
+                            kafkaConfigService.getConfigParams().getIpAddress(),
+                            kafkaConfigService.getConfigParams().getPort());
+
+        return response;
     }
 
     @Override
@@ -147,16 +157,11 @@ public class EventSubscriptionManager implements EventSubscriptionService {
                     + "registered to make this request.");
         }
 
-        if (!validGroupId(subscriber.subscriberGroupId(), subscriber.appName())) {
+        if (!validGroupId(subscriber.subscriberGroupId(),
+                          subscriber.appName())) {
             throw new InvalidGroupIdException("Incorrect group id in the request");
         }
 
-        OnosEventListener onosListener = getListener(subscriber.eventType());
-        checkNotNull(onosListener, "No listener for the supported event type - {}", subscriber.eventType());
-
-        applyListenerAction(subscriber.eventType(), onosListener,
-                            ListenerAction.START);
-
         // update internal state
         List<EventSubscriber> subscriptionList =
                 subscriptions.get(subscriber.eventType());
@@ -233,12 +238,6 @@ public class EventSubscriptionManager implements EventSubscriptionService {
      * @param eventType ONOS event type
      * @return ONOS event listener
      */
-    private OnosEventListener getListener(Type eventType) {
-        checkNotNull(eventType);
-        ListenerFactory factory = ListenerFactory.getInstance();
-        OnosEventListener onosListener = factory.getListener(eventType);
-        return onosListener;
-    }
 
     /**
      * Checks if the group id is valid for this registered application.
@@ -287,15 +286,6 @@ public class EventSubscriptionManager implements EventSubscriptionService {
         // stop the listener.
         List<EventSubscriber> subscribers =
                 subscriptions.get(subscriber.eventType());
-        if (subscribers.size() == 1) {
-            OnosEventListener onosListener =
-                    getListener(subscriber.eventType());
-            checkNotNull(onosListener,
-                         "No listener for the supported event type - {}",
-                         subscriber.eventType());
-            applyListenerAction(subscriber.eventType(), onosListener,
-                                ListenerAction.STOP);
-        }
 
         // update internal state.
         subscribers.remove(subscriber);
@@ -308,7 +298,6 @@ public class EventSubscriptionManager implements EventSubscriptionService {
     @Override
     public List<EventSubscriber> getEventSubscribers(Type type) {
         return subscriptions.getOrDefault(type, ImmutableList.of());
-
     }
 
     /**

@@ -31,7 +31,7 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
-@Component(immediate = true)
+@Component(immediate = false)
 public class KafkaStorageManager implements KafkaEventStorageService {
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)

@@ -19,36 +19,32 @@ package org.onosproject.kafkaintegration.kafka;
 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.Modified;
-import org.apache.felix.scr.annotations.Property;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.kafka.clients.producer.ProducerRecord;
-import org.onosproject.cfg.ComponentConfigService;
 import org.onosproject.kafkaintegration.api.EventConversionService;
 import org.onosproject.kafkaintegration.api.EventSubscriptionService;
+import org.onosproject.kafkaintegration.api.KafkaProducerService;
+import org.onosproject.kafkaintegration.api.KafkaConfigService;
+import org.onosproject.kafkaintegration.api.dto.OnosEvent;
 import org.onosproject.net.device.DeviceEvent;
 import org.onosproject.net.device.DeviceListener;
 import org.onosproject.net.device.DeviceService;
 import org.onosproject.net.link.LinkEvent;
 import org.onosproject.net.link.LinkListener;
 import org.onosproject.net.link.LinkService;
-import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.Dictionary;
-import java.util.UUID;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 
-import static com.google.common.base.Strings.isNullOrEmpty;
 import static java.util.concurrent.Executors.newSingleThreadScheduledExecutor;
-import static org.onlab.util.Tools.get;
 import static org.onlab.util.Tools.groupedThreads;
 import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.DEVICE;
 import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.LINK;
 
+
 /**
  * Encapsulates the behavior of monitoring various ONOS events.
  * */
@@ -63,152 +59,66 @@ public class EventMonitor {
     protected EventConversionService eventConversionService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected KafkaProducerService kafkaProducer;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected DeviceService deviceService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected LinkService linkService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected ComponentConfigService componentConfigService;
+    protected KafkaConfigService kafkaConfigService;
 
     private final DeviceListener deviceListener = new InternalDeviceListener();
     private final LinkListener linkListener = new InternalLinkListener();
 
     protected ExecutorService eventExecutor;
 
-    private static final String BOOTSTRAP_SERVERS = "localhost:9092";
-    private static final int RETRIES = 1;
-    private static final int MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION = 5;
-    private static final int REQUEST_REQUIRED_ACKS = 1;
-    private static final String KEY_SERIALIZER = "org.apache.kafka.common.serialization.StringSerializer";
-    private static final String VALUE_SERIALIZER = "org.apache.kafka.common.serialization.ByteArraySerializer";
-
-    @Property(name = "bootstrap.servers", value = BOOTSTRAP_SERVERS,
-            label = "Default host/post pair to establish initial connection to Kafka cluster.")
-    private String bootstrapServers = BOOTSTRAP_SERVERS;
-
-    @Property(name = "retries", intValue = RETRIES,
-            label = "Number of times the producer can retry to send after first failure")
-    private int retries = RETRIES;
-
-    @Property(name = "max.in.flight.requests.per.connection", intValue = MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION,
-            label = "The maximum number of unacknowledged requests the client will send before blocking")
-    private int maxInFlightRequestsPerConnection = MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION;
-
-    @Property(name = "request.required.acks", intValue = 1,
-            label = "Producer will get an acknowledgement after the leader has replicated the data")
-    private int requestRequiredAcks = REQUEST_REQUIRED_ACKS;
-
-    @Property(name = "key.serializer", value = KEY_SERIALIZER,
-            label = "Serializer class for key that implements the Serializer interface.")
-    private String keySerializer = KEY_SERIALIZER;
-
-    @Property(name = "value.serializer", value = VALUE_SERIALIZER,
-            label = "Serializer class for value that implements the Serializer interface.")
-    private String valueSerializer = VALUE_SERIALIZER;
-
-    private Producer producer;
-
     @Activate
-    protected void activate(ComponentContext context) {
-        componentConfigService.registerProperties(getClass());
+    protected void activate() {
+
         eventExecutor = newSingleThreadScheduledExecutor(groupedThreads("onos/onosEvents", "events-%d", log));
         deviceService.addListener(deviceListener);
         linkService.addListener(linkListener);
-        producer = new Producer(bootstrapServers, retries, maxInFlightRequestsPerConnection,
-                                requestRequiredAcks, keySerializer, valueSerializer);
-        producer.start();
+
+        kafkaProducer.start(kafkaConfigService.getConfigParams());
 
         log.info("Started");
     }
 
     @Deactivate
     protected void deactivate() {
-        componentConfigService.unregisterProperties(getClass(), false);
         deviceService.removeListener(deviceListener);
         linkService.removeListener(linkListener);
-        producer.stop();
+
         eventExecutor.shutdownNow();
         eventExecutor = null;
 
-        log.info("Stopped");
-    }
-
-    @Modified
-    private void modified(ComponentContext context) {
-        if (context == null) {
-            bootstrapServers = BOOTSTRAP_SERVERS;
-            retries = RETRIES;
-            maxInFlightRequestsPerConnection = MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION;
-            requestRequiredAcks = REQUEST_REQUIRED_ACKS;
-            keySerializer = KEY_SERIALIZER;
-            valueSerializer = VALUE_SERIALIZER;
-            return;
-        }
-        Dictionary properties = context.getProperties();
+        kafkaProducer.stop();
 
-        String newBootstrapServers = BOOTSTRAP_SERVERS;
-        int newRetries = RETRIES;
-        int newMaxInFlightRequestsPerConnection = MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION;
-        int newRequestRequiredAcks = REQUEST_REQUIRED_ACKS;
-        try {
-            String s = get(properties, "bootstrapServers");
-            newBootstrapServers = isNullOrEmpty(s)
-                    ? bootstrapServers : s.trim();
-
-            s = get(properties, "retries");
-            newRetries = isNullOrEmpty(s)
-                    ? retries : Integer.parseInt(s.trim());
-
-            s = get(properties, "maxInFlightRequestsPerConnection");
-            newMaxInFlightRequestsPerConnection = isNullOrEmpty(s)
-                    ? maxInFlightRequestsPerConnection : Integer.parseInt(s.trim());
-
-            s = get(properties, "requestRequiredAcks");
-            newRequestRequiredAcks = isNullOrEmpty(s)
-                    ? requestRequiredAcks : Integer.parseInt(s.trim());
-
-        } catch (NumberFormatException | ClassCastException e) {
-            return;
-        }
-
-        boolean modified = newBootstrapServers != bootstrapServers ||
-                newRetries != retries ||
-                newMaxInFlightRequestsPerConnection != maxInFlightRequestsPerConnection ||
-                newRequestRequiredAcks != requestRequiredAcks;
-
-        if (modified) {
-            bootstrapServers = newBootstrapServers;
-            retries = newRetries;
-            maxInFlightRequestsPerConnection = newMaxInFlightRequestsPerConnection;
-            requestRequiredAcks = newRequestRequiredAcks;
-            if (producer != null) {
-                producer.stop();
-            }
-            producer = new Producer(bootstrapServers, retries, maxInFlightRequestsPerConnection,
-                                        requestRequiredAcks, keySerializer, valueSerializer);
-            producer.start();
-            log.info("Modified");
-        } else {
-            return;
-        }
+        log.info("Stopped");
     }
 
     private class InternalDeviceListener implements DeviceListener {
 
         @Override
         public void event(DeviceEvent event) {
+
             if (!eventSubscriptionService.getEventSubscribers(DEVICE).isEmpty()) {
+                OnosEvent onosEvent = eventConversionService.convertEvent(event);
                 eventExecutor.execute(() -> {
                     try {
-                        String id = UUID.randomUUID().toString();
-                        producer.send(new ProducerRecord<>(DEVICE.toString(),
-                                                                id, event.subject().toString().getBytes())).get();
-                        log.debug("Device event sent successfully.");
-                    } catch (InterruptedException e) {
+                        kafkaProducer.send(new ProducerRecord<>(DEVICE.toString(),
+                                                               onosEvent.subject().toByteArray())).get();
+
+                        log.debug("Event Type - {}, Subject {} sent successfully.",
+                                  DEVICE, onosEvent.subject());
+
+                    } catch (InterruptedException e1) {
                         Thread.currentThread().interrupt();
-                    } catch (ExecutionException e) {
-                        log.error("Exception thrown {}", e);
+                    } catch (ExecutionException e2) {
+                        log.error("Exception thrown {}", e2);
                     }
                 });
             } else {
@@ -221,17 +131,21 @@ public class EventMonitor {
 
         @Override
         public void event(LinkEvent event) {
+
             if (!eventSubscriptionService.getEventSubscribers(LINK).isEmpty()) {
+                OnosEvent onosEvent = eventConversionService.convertEvent(event);
                 eventExecutor.execute(() -> {
                     try {
-                        String id = UUID.randomUUID().toString();
-                        producer.send(new ProducerRecord<>(LINK.toString(),
-                                                                id, event.subject().toString().getBytes())).get();
-                        log.debug("Link event sent successfully.");
-                    } catch (InterruptedException e) {
+                        kafkaProducer.send(new ProducerRecord<>(LINK.toString(),
+                                onosEvent.subject().toByteArray())).get();
+
+                        log.debug("Event Type - {}, Subject {} sent successfully.",
+                              LINK, onosEvent.subject());
+
+                    } catch (InterruptedException e1) {
                         Thread.currentThread().interrupt();
-                    } catch (ExecutionException e) {
-                        log.error("Exception thrown {}", e);
+                    } catch (ExecutionException e2) {
+                        log.error("Exception thrown {}", e2);
                     }
                 });
             } else {

+/**
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.kafkaintegration.kafka;
+
+import static com.google.common.base.Strings.isNullOrEmpty;
+import static org.onlab.util.Tools.get;
+
+import java.util.Dictionary;
+
+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.Modified;
+import org.apache.felix.scr.annotations.Property;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.kafkaintegration.api.KafkaConfigService;
+import org.onosproject.kafkaintegration.api.KafkaProducerService;
+import org.onosproject.kafkaintegration.api.dto.KafkaServerConfig;
+import org.osgi.service.component.ComponentContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Component(immediate = true)
+@Service
+public class KafkaConfigManager implements KafkaConfigService {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ComponentConfigService componentConfigService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected KafkaProducerService producer;
+
+    public static final String BOOTSTRAP_SERVERS = "localhost:9092";
+    private String kafkaServerIp =
+            BOOTSTRAP_SERVERS.substring(0, BOOTSTRAP_SERVERS.indexOf(":"));
+    private String kafkaServerPortNum =
+            BOOTSTRAP_SERVERS.substring(BOOTSTRAP_SERVERS.indexOf(":") + 1,
+                                        BOOTSTRAP_SERVERS.length());
+
+    private static final int RETRIES = 1;
+    private static final int MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION = 5;
+    private static final int REQUEST_REQUIRED_ACKS = 1;
+    private static final String KEY_SERIALIZER =
+            "org.apache.kafka.common.serialization.StringSerializer";
+    private static final String VALUE_SERIALIZER =
+            "org.apache.kafka.common.serialization.ByteArraySerializer";
+
+    @Property(name = "bootstrap.servers", value = BOOTSTRAP_SERVERS,
+            label = "Default IP/Port pair to establish initial connection to Kafka cluster.")
+    protected String bootstrapServers = BOOTSTRAP_SERVERS;
+
+    @Property(name = "retries", intValue = RETRIES,
+            label = "Number of times the producer can retry to send after first failure")
+    protected int retries = RETRIES;
+
+    @Property(name = "max.in.flight.requests.per.connection",
+            intValue = MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION,
+            label = "The maximum number of unacknowledged requests the client will send before blocking")
+    protected int maxInFlightRequestsPerConnection =
+            MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION;
+
+    @Property(name = "request.required.acks", intValue = 1,
+            label = "Producer will get an acknowledgement after the leader has replicated the data")
+    protected int requestRequiredAcks = REQUEST_REQUIRED_ACKS;
+
+    @Property(name = "key.serializer", value = KEY_SERIALIZER,
+            label = "Serializer class for key that implements the Serializer interface.")
+    protected String keySerializer = KEY_SERIALIZER;
+
+    @Property(name = "value.serializer", value = VALUE_SERIALIZER,
+            label = "Serializer class for value that implements the Serializer interface.")
+    protected String valueSerializer = VALUE_SERIALIZER;
+
+    @Activate
+    protected void activate(ComponentContext context) {
+        componentConfigService.registerProperties(getClass());
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        componentConfigService.unregisterProperties(getClass(), false);
+        log.info("Stopped");
+    }
+
+    @Modified
+    private void modified(ComponentContext context) {
+        if (context == null) {
+            bootstrapServers = BOOTSTRAP_SERVERS;
+            retries = RETRIES;
+            maxInFlightRequestsPerConnection =
+                    MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION;
+            requestRequiredAcks = REQUEST_REQUIRED_ACKS;
+            keySerializer = KEY_SERIALIZER;
+            valueSerializer = VALUE_SERIALIZER;
+            return;
+        }
+
+        Dictionary<?, ?> properties = context.getProperties();
+
+        String newBootstrapServers;
+        int newRetries;
+        int newMaxInFlightRequestsPerConnection;
+        int newRequestRequiredAcks;
+        try {
+            String s = get(properties, "bootstrap.servers");
+            newBootstrapServers =
+                    isNullOrEmpty(s) ? bootstrapServers : s.trim();
+
+            s = get(properties, "retries");
+            newRetries =
+                    isNullOrEmpty(s) ? retries : Integer.parseInt(s.trim());
+
+            s = get(properties, "max.in.flight.requests.per.connection");
+            newMaxInFlightRequestsPerConnection =
+                    isNullOrEmpty(s) ? maxInFlightRequestsPerConnection
+                                     : Integer.parseInt(s.trim());
+
+            s = get(properties, "request.required.acks");
+            newRequestRequiredAcks =
+                    isNullOrEmpty(s) ? requestRequiredAcks
+                                     : Integer.parseInt(s.trim());
+
+        } catch (NumberFormatException | ClassCastException e) {
+            return;
+        }
+
+        if (configModified(newBootstrapServers, newRetries,
+                           newMaxInFlightRequestsPerConnection,
+                           newRequestRequiredAcks)) {
+            bootstrapServers = newBootstrapServers;
+            kafkaServerIp = bootstrapServers
+                    .substring(0, bootstrapServers.indexOf(":"));
+            kafkaServerPortNum = bootstrapServers
+                    .substring(bootstrapServers.indexOf(":") + 1,
+                               bootstrapServers.length());
+
+            retries = newRetries;
+
+            maxInFlightRequestsPerConnection =
+                    newMaxInFlightRequestsPerConnection;
+
+            requestRequiredAcks = newRequestRequiredAcks;
+
+            producer.restart(KafkaServerConfig.builder()
+                    .ipAddress(kafkaServerIp).port(kafkaServerPortNum)
+                    .numOfRetries(retries)
+                    .maxInFlightRequestsPerConnection(maxInFlightRequestsPerConnection)
+                    .acksRequired(requestRequiredAcks)
+                    .keySerializer(keySerializer)
+                    .valueSerializer(valueSerializer).build());
+
+            log.info("Kafka Server Config has been Modified - "
+                    + "bootstrapServers {}, retries {}, "
+                    + "maxInFlightRequestsPerConnection {}, "
+                    + "requestRequiredAcks {}", bootstrapServers, retries,
+                     maxInFlightRequestsPerConnection, requestRequiredAcks);
+        } else {
+            return;
+        }
+    }
+
+    private boolean configModified(String newBootstrapServers, int newRetries,
+                                   int newMaxInFlightRequestsPerConnection,
+                                   int newRequestRequiredAcks) {
+
+        return !newBootstrapServers.equals(bootstrapServers)
+                || newRetries != retries
+                || newMaxInFlightRequestsPerConnection != maxInFlightRequestsPerConnection
+                || newRequestRequiredAcks != requestRequiredAcks;
+
+    }
+
+    @Override
+    public KafkaServerConfig getConfigParams() {
+        String ipAddr =
+                bootstrapServers.substring(0, bootstrapServers.indexOf(":"));
+        String port =
+                bootstrapServers.substring(bootstrapServers.indexOf(":") + 1,
+                                           bootstrapServers.length());
+
+        return KafkaServerConfig.builder().ipAddress(ipAddr).port(port)
+                .numOfRetries(retries)
+                .maxInFlightRequestsPerConnection(maxInFlightRequestsPerConnection)
+                .acksRequired(requestRequiredAcks).keySerializer(keySerializer)
+                .valueSerializer(valueSerializer).build();
+
+    }
+
+}

@@ -16,50 +16,84 @@
 
 package org.onosproject.kafkaintegration.kafka;
 
+import java.util.Properties;
+import java.util.concurrent.Future;
+
+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.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.ProducerRecord;
 import org.apache.kafka.clients.producer.RecordMetadata;
+import org.onosproject.kafkaintegration.api.KafkaProducerService;
+import org.onosproject.kafkaintegration.api.dto.KafkaServerConfig;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.Properties;
-import java.util.concurrent.Future;
-
 /**
- * Implementation of Kafka Producer.
+ * Implementation of a Kafka Producer.
  */
-public class Producer {
+@Component
+@Service
+public class Producer implements KafkaProducerService {
     private KafkaProducer<String, byte[]> kafkaProducer = null;
 
     private final Logger log = LoggerFactory.getLogger(getClass());
 
-    Producer(String bootstrapServers, int retries, int maxInFlightRequestsPerConnection,
-             int requestRequiredAcks, String keySerializer, String valueSerializer) {
+    @Activate
+    protected void activate() {
+        log.info("Started");
+    }
 
-        Properties prop = new Properties();
-        prop.put("bootstrap.servers", bootstrapServers);
-        prop.put("retries", retries);
-        prop.put("max.in.flight.requests.per.connection", maxInFlightRequestsPerConnection);
-        prop.put("request.required.acks", requestRequiredAcks);
-        prop.put("key.serializer", keySerializer);
-        prop.put("value.serializer", valueSerializer);
+    @Deactivate
+    protected void deactivate() {
+        log.info("Stopped");
+    }
 
-        kafkaProducer = new KafkaProducer<>(prop);
+    @Override
+    public void start(KafkaServerConfig config) {
+
+        if (kafkaProducer != null) {
+            log.info("Producer has already started");
+            return;
         }
 
-    public void start() {
-        log.info("Started");
+        String bootstrapServer =
+                new StringBuilder().append(config.getIpAddress()).append(":")
+                        .append(config.getPort()).toString();
+
+        // Set Server Properties
+        Properties prop = new Properties();
+        prop.put("bootstrap.servers", bootstrapServer);
+        prop.put("retries", config.getNumOfRetries());
+        prop.put("max.in.flight.requests.per.connection",
+                 config.getMaxInFlightRequestsPerConnection());
+        prop.put("request.required.acks", config.getAcksRequired());
+        prop.put("key.serializer", config.getKeySerializer());
+        prop.put("value.serializer", config.getValueSerializer());
+
+        kafkaProducer = new KafkaProducer<>(prop);
+        log.info("Kafka Producer has started.");
     }
 
+    @Override
     public void stop() {
         if (kafkaProducer != null) {
             kafkaProducer.close();
             kafkaProducer = null;
         }
 
-        log.info("Stopped");
+        log.info("Kafka Producer has Stopped");
+    }
+
+    @Override
+    public void restart(KafkaServerConfig config) {
+        stop();
+        start(config);
     }
 
+    @Override
     public Future<RecordMetadata> send(ProducerRecord<String, byte[]> record) {
         return kafkaProducer.send(record);
     }

-/**
- * Copyright 2016 Open Networking Laboratory
- * 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 org.onosproject.kafkaintegration.listener;
-
-import com.google.protobuf.GeneratedMessage;
-import org.onosproject.event.ListenerService;
-import org.onosproject.kafkaintegration.api.dto.OnosEvent.Type;
-import org.onosproject.kafkaintegration.converter.ConversionFactory;
-import org.onosproject.kafkaintegration.converter.EventConverter;
-import org.onosproject.kafkaintegration.impl.KafkaPublisherManager;
-import org.onosproject.net.device.DeviceEvent;
-import org.onosproject.net.device.DeviceListener;
-import org.onosproject.net.device.DeviceService;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.DEVICE;
-
-/**
- * Listens for ONOS Device events.
- *
- */
-public final class DeviceEventsListener implements OnosEventListener {
-
-    private final Logger log = LoggerFactory.getLogger(getClass());
-
-    private boolean listenerRunning = false;
-
-    private InnerListener listener = null;
-    // Exists to defeat instantiation
-    private DeviceEventsListener() {
-    }
-
-    private static class SingletonHolder {
-        private static final DeviceEventsListener INSTANCE =
-                new DeviceEventsListener();
-    }
-
-    /**
-     * Returns a static reference to the Listener Factory.
-     *
-     * @return singleton object
-     */
-    public static DeviceEventsListener getInstance() {
-        return SingletonHolder.INSTANCE;
-    }
-
-    @Override
-    public void startListener(Type e, ListenerService<?, ?> service) {
-        if (!listenerRunning) {
-            listener = new InnerListener();
-            DeviceService deviceService = (DeviceService) service;
-            deviceService.addListener(listener);
-            listenerRunning = true;
-        }
-    }
-
-    private class InnerListener implements DeviceListener {
-
-        @Override
-        public void event(DeviceEvent arg0) {
-
-            // Convert the event to protobuf format
-            ConversionFactory conversionFactory =
-                    ConversionFactory.getInstance();
-            EventConverter converter = conversionFactory.getConverter(DEVICE);
-            GeneratedMessage message = converter.convertToProtoMessage(arg0);
-
-            // Call Dispatcher and publish event
-            KafkaPublisherManager.getInstance().publish(DEVICE, message);
-        }
-    }
-
-    @Override
-    public void stopListener(Type e, ListenerService<?, ?> service) {
-        if (listenerRunning) {
-            DeviceService deviceService = (DeviceService) service;
-            deviceService.removeListener(listener);
-            listener = null;
-            listenerRunning = false;
-        }
-    }
-
-}
\ No newline at end of file

-/**
- * Copyright 2016 Open Networking Laboratory
- * 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 org.onosproject.kafkaintegration.listener;
-
-import com.google.protobuf.GeneratedMessage;
-import org.onosproject.event.ListenerService;
-import org.onosproject.kafkaintegration.api.dto.OnosEvent.Type;
-import org.onosproject.kafkaintegration.converter.ConversionFactory;
-import org.onosproject.kafkaintegration.converter.EventConverter;
-import org.onosproject.kafkaintegration.impl.KafkaPublisherManager;
-import org.onosproject.net.link.LinkEvent;
-import org.onosproject.net.link.LinkListener;
-import org.onosproject.net.link.LinkService;
-
-import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.LINK;
-
-/**
- * Listens for ONOS Link Events.
- *
- */
-public final class LinkEventsListener implements OnosEventListener {
-
-    private boolean listenerRunning = false;
-
-    private InnerListener listener = null;
-    // Exists to defeat instantiation
-    private LinkEventsListener() {
-    }
-
-    private static class SingletonHolder {
-        private static final LinkEventsListener INSTANCE =
-                new LinkEventsListener();
-    }
-
-    /**
-     * Returns a static reference to the Listener Factory.
-     *
-     * @return singleton object
-     */
-    public static LinkEventsListener getInstance() {
-        return SingletonHolder.INSTANCE;
-    }
-
-    @Override
-    public void startListener(Type e, ListenerService<?, ?> service) {
-        if (!listenerRunning) {
-            listener = new InnerListener();
-            LinkService linkService = (LinkService) service;
-            linkService.addListener(listener);
-            listenerRunning = true;
-        }
-    }
-
-    private class InnerListener implements LinkListener {
-
-        @Override
-        public void event(LinkEvent arg0) {
-
-            // Convert the event to protobuf format
-            ConversionFactory conversionFactory =
-                    ConversionFactory.getInstance();
-            EventConverter converter = conversionFactory.getConverter(LINK);
-            GeneratedMessage message = converter.convertToProtoMessage(arg0);
-
-            // Call Dispatcher and publish event
-            KafkaPublisherManager.getInstance().publish(LINK, message);
-        }
-    }
-
-    @Override
-    public void stopListener(Type e, ListenerService<?, ?> service) {
-        if (listenerRunning) {
-            LinkService linkService = (LinkService) service;
-            linkService.removeListener(listener);
-            listenerRunning = false;
-        }
-    }
-}

-/**
- * Copyright 2016 Open Networking Laboratory
- * 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 org.onosproject.kafkaintegration.listener;
-
-import org.onosproject.kafkaintegration.api.dto.OnosEvent.Type;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.DEVICE;
-import static org.onosproject.kafkaintegration.api.dto.OnosEvent.Type.LINK;
-
-/**
- * Returns the appropriate listener object based on the ONOS event type.
- *
- */
-public final class ListenerFactory {
-
-    // Store listeners for all supported events
-    private Map<Type, OnosEventListener> listeners =
-            new HashMap<Type, OnosEventListener>() {
-                {
-                    put(DEVICE, DeviceEventsListener.getInstance());
-                    put(LINK, LinkEventsListener.getInstance());
-                }
-            };
-
-    // Exists to defeat instantiation
-    private ListenerFactory() {
-    }
-
-    private static class SingletonHolder {
-        private static final ListenerFactory INSTANCE = new ListenerFactory();
-    }
-
-    /**
-     * Returns a static reference to the Listener Factory.
-     *
-     * @return singleton object
-     */
-    public static ListenerFactory getInstance() {
-        return SingletonHolder.INSTANCE;
-    }
-
-    /**
-     * Returns the listener object for the specified ONOS event type.
-     *
-     * @param event ONOS Event type
-     * @return return listener object
-     */
-    public OnosEventListener getListener(Type event) {
-        return listeners.get(event);
-    }
-
-}

@@ -200,6 +200,7 @@
                     </execution>
                     <execution>
                         <id>swagger</id>
+                        <phase>generate-resources</phase>
                         <goals>
                             <goal>swagger</goal>
                         </goals>

@@ -18,12 +18,11 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import org.onosproject.kafkaintegration.api.EventSubscriptionService;
 import org.onosproject.kafkaintegration.api.dto.EventSubscriber;
-import org.onosproject.kafkaintegration.api.dto.EventSubscriberGroupId;
+import org.onosproject.kafkaintegration.api.dto.RegistrationResponse;
 import org.onosproject.rest.AbstractWebResource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-
 import javax.ws.rs.Consumes;
 import javax.ws.rs.DELETE;
 import javax.ws.rs.POST;
@@ -62,7 +61,7 @@ public class EventExporterWebResource extends AbstractWebResource {
      *
      * @param appName The application trying to register
      * @return 200 OK with UUID string which should be used as Kafka Consumer
-     *         Group Id
+     *         Group Id and Kafka Server, port information.
      * @onos.rsModel KafkaRegistration
      */
     @POST
@@ -73,12 +72,16 @@ public class EventExporterWebResource extends AbstractWebResource {
 
         EventSubscriptionService service = get(EventSubscriptionService.class);
 
-        EventSubscriberGroupId groupId = service.registerListener(appName);
+        RegistrationResponse response = service.registerListener(appName);
+
+        ObjectNode result = mapper().createObjectNode();
+        result.put("groupId", response.getGroupId().getId().toString());
+        result.put("ipAddress", response.getIpAddress());
+        result.put("port", response.getPort());
 
         log.info("Registered app {}", appName);
-        // TODO: Should also return Kafka server information.
-        // Will glue this in when we have the config and Kafka modules ready
-        return ok(groupId.getId().toString()).build();
+
+        return ok(result.toString()).build();
     }
 
     /**