Merge "Bug 2517: Catch RuntimeExceptions thrown from the DCL in DataChangeListener"
[controller.git] / opendaylight / md-sal / sal-rest-connector / src / main / java / org / opendaylight / controller / sal / streams / listeners / ListenerAdapter.java
index fdd6ba0317d597dd1483c4a54dcd647e4734b6cc..8481a9f0c8129f0a90f379dc5ca409d1bfc6b552 100644 (file)
@@ -1,9 +1,20 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
 package org.opendaylight.controller.sal.streams.listeners;
 
+import com.google.common.base.Charsets;
+import com.google.common.base.Preconditions;
+import com.google.common.eventbus.AsyncEventBus;
+import com.google.common.eventbus.EventBus;
+import com.google.common.eventbus.Subscribe;
 import io.netty.channel.Channel;
 import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
 import io.netty.util.internal.ConcurrentSet;
-
 import java.io.ByteArrayOutputStream;
 import java.io.OutputStreamWriter;
 import java.io.UnsupportedEncodingException;
@@ -16,7 +27,7 @@ import java.util.Map.Entry;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.Executors;
-
+import java.util.regex.Pattern;
 import javax.activation.UnsupportedDataTypeException;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -27,18 +38,18 @@ import javax.xml.transform.TransformerException;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
-
-import org.opendaylight.controller.md.sal.common.api.data.DataChangeEvent;
-import org.opendaylight.controller.sal.core.api.data.DataChangeListener;
+import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeEvent;
+import org.opendaylight.controller.md.sal.dom.api.DOMDataChangeListener;
 import org.opendaylight.controller.sal.rest.impl.XmlMapper;
 import org.opendaylight.controller.sal.restconf.impl.ControllerContext;
 import org.opendaylight.yangtools.concepts.ListenerRegistration;
 import org.opendaylight.yangtools.yang.common.QName;
 import org.opendaylight.yangtools.yang.data.api.CompositeNode;
-import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
-import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.NodeIdentifierWithPredicates;
-import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.NodeWithValue;
-import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier.PathArgument;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifierWithPredicates;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeWithValue;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
 import org.opendaylight.yangtools.yang.model.api.DataNodeContainer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -46,25 +57,35 @@ import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
 
-import com.google.common.base.Preconditions;
-import com.google.common.eventbus.AsyncEventBus;
-import com.google.common.eventbus.EventBus;
-import com.google.common.eventbus.Subscribe;
+/**
+ * {@link ListenerAdapter} is responsible to track events, which occurred by changing data in data source.
+ */
+public class ListenerAdapter implements DOMDataChangeListener {
 
-public class ListenerAdapter implements DataChangeListener {
+    private static final Logger LOG = LoggerFactory.getLogger(ListenerAdapter.class);
+    private static final DocumentBuilderFactory DBF = DocumentBuilderFactory.newInstance();
+    private static final TransformerFactory FACTORY = TransformerFactory.newInstance();
+    private static final Pattern RFC3339_PATTERN = Pattern.compile("(\\d\\d)(\\d\\d)$");
 
-    private static final Logger logger = LoggerFactory.getLogger(ListenerAdapter.class);
     private final XmlMapper xmlMapper = new XmlMapper();
     private final SimpleDateFormat rfc3339 = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ssZ");
 
-    private final InstanceIdentifier path;
-    private ListenerRegistration<DataChangeListener> registration;
+    private final YangInstanceIdentifier path;
+    private ListenerRegistration<DOMDataChangeListener> registration;
     private final String streamName;
     private Set<Channel> subscribers = new ConcurrentSet<>();
     private final EventBus eventBus;
     private final EventBusChangeRecorder eventBusChangeRecorder;
 
-    ListenerAdapter(InstanceIdentifier path, String streamName) {
+    /**
+     * Creates new {@link ListenerAdapter} listener specified by path and stream name.
+     *
+     * @param path
+     *            Path to data in data store.
+     * @param streamName
+     *            The name of the stream.
+     */
+    ListenerAdapter(final YangInstanceIdentifier path, final String streamName) {
         Preconditions.checkNotNull(path);
         Preconditions.checkArgument(streamName != null && !streamName.isEmpty());
         this.path = path;
@@ -75,21 +96,26 @@ public class ListenerAdapter implements DataChangeListener {
     }
 
     @Override
-    public void onDataChanged(DataChangeEvent<InstanceIdentifier, CompositeNode> change) {
-        if (!change.getCreatedConfigurationData().isEmpty() || !change.getCreatedOperationalData().isEmpty()
-                || !change.getUpdatedConfigurationData().isEmpty() || !change.getUpdatedOperationalData().isEmpty()
-                || !change.getRemovedConfigurationData().isEmpty() || !change.getRemovedOperationalData().isEmpty()) {
-            String xml = prepareXmlFrom(change);
-            Event event = new Event(EventType.NOTIFY);
+    public void onDataChanged(final AsyncDataChangeEvent<YangInstanceIdentifier, NormalizedNode<?, ?>> change) {
+        // TODO Auto-generated method stub
+
+        if (!change.getCreatedData().isEmpty() || !change.getUpdatedData().isEmpty()
+                || !change.getRemovedPaths().isEmpty()) {
+            final String xml = prepareXmlFrom(change);
+            final Event event = new Event(EventType.NOTIFY);
             event.setData(xml);
             eventBus.post(event);
         }
     }
 
+    /**
+     * Tracks events of data change by customer.
+     */
     private final class EventBusChangeRecorder {
-        @Subscribe public void recordCustomerChange(Event event) {
+        @Subscribe
+        public void recordCustomerChange(final Event event) {
             if (event.getType() == EventType.REGISTER) {
-                Channel subscriber = event.getSubscriber();
+                final Channel subscriber = event.getSubscriber();
                 if (!subscribers.contains(subscriber)) {
                     subscribers.add(subscriber);
                 }
@@ -97,12 +123,12 @@ public class ListenerAdapter implements DataChangeListener {
                 subscribers.remove(event.getSubscriber());
                 Notificator.removeListenerIfNoSubscriberExists(ListenerAdapter.this);
             } else if (event.getType() == EventType.NOTIFY) {
-                for (Channel subscriber : subscribers) {
+                for (final Channel subscriber : subscribers) {
                     if (subscriber.isActive()) {
-                        logger.debug("Data are sent to subscriber {}:", subscriber.remoteAddress());
+                        LOG.debug("Data are sent to subscriber {}:", subscriber.remoteAddress());
                         subscriber.writeAndFlush(new TextWebSocketFrame(event.getData()));
                     } else {
-                        logger.debug("Subscriber {} is removed - channel is not active yet.", subscriber.remoteAddress());
+                        LOG.debug("Subscriber {} is removed - channel is not active yet.", subscriber.remoteAddress());
                         subscribers.remove(subscriber);
                     }
                 }
@@ -110,148 +136,253 @@ public class ListenerAdapter implements DataChangeListener {
         }
     }
 
+    /**
+     * Represents event of specific {@link EventType} type, holds data and {@link Channel} subscriber.
+     */
     private final class Event {
         private final EventType type;
         private Channel subscriber;
         private String data;
 
-        public Event(EventType type) {
+        /**
+         * Creates new event specified by {@link EventType} type.
+         *
+         * @param type
+         *            EventType
+         */
+        public Event(final EventType type) {
             this.type = type;
         }
 
+        /**
+         * Gets the {@link Channel} subscriber.
+         *
+         * @return Channel
+         */
         public Channel getSubscriber() {
             return subscriber;
         }
 
-        public void setSubscriber(Channel subscriber) {
+        /**
+         * Sets subscriber for event.
+         *
+         * @param subscriber
+         *            Channel
+         */
+        public void setSubscriber(final Channel subscriber) {
             this.subscriber = subscriber;
         }
 
+        /**
+         * Gets event data.
+         *
+         * @return String representation of event data.
+         */
         public String getData() {
             return data;
         }
 
-        public void setData(String data) {
+        /**
+         * Sets event data.
+         *
+         * @param String
+         *            data.
+         */
+        public void setData(final String data) {
             this.data = data;
         }
 
+        /**
+         * Gets event type.
+         *
+         * @return The type of the event.
+         */
         public EventType getType() {
             return type;
         }
     }
 
+    /**
+     * Type of the event.
+     */
     private enum EventType {
         REGISTER,
         DEREGISTER,
         NOTIFY;
     }
 
-    private String prepareXmlFrom(DataChangeEvent<InstanceIdentifier, CompositeNode> change) {
-        Document doc = createDocument();
-        Element notificationElement = doc.createElementNS("urn:ietf:params:xml:ns:netconf:notification:1.0",
+    /**
+     * Prepare data in printable form and transform it to String.
+     *
+     * @param change
+     *            DataChangeEvent
+     * @return Data in printable form.
+     */
+    private String prepareXmlFrom(final AsyncDataChangeEvent<YangInstanceIdentifier, NormalizedNode<?, ?>> change) {
+        final Document doc = createDocument();
+        final Element notificationElement = doc.createElementNS("urn:ietf:params:xml:ns:netconf:notification:1.0",
                 "notification");
         doc.appendChild(notificationElement);
 
-        Element eventTimeElement = doc.createElement("eventTime");
+        final Element eventTimeElement = doc.createElement("eventTime");
         eventTimeElement.setTextContent(toRFC3339(new Date()));
         notificationElement.appendChild(eventTimeElement);
 
-        Element dataChangedNotificationEventElement = doc.createElementNS(
+        final Element dataChangedNotificationEventElement = doc.createElementNS(
                 "urn:opendaylight:params:xml:ns:yang:controller:md:sal:remote", "data-changed-notification");
         addValuesToDataChangedNotificationEventElement(doc, dataChangedNotificationEventElement, change);
         notificationElement.appendChild(dataChangedNotificationEventElement);
 
         try {
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-            TransformerFactory tf = TransformerFactory.newInstance();
-            Transformer transformer = tf.newTransformer();
+            final ByteArrayOutputStream out = new ByteArrayOutputStream();
+            final Transformer transformer = FACTORY.newTransformer();
             transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
             transformer.setOutputProperty(OutputKeys.METHOD, "xml");
             transformer.setOutputProperty(OutputKeys.INDENT, "yes");
             transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
             transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
-            transformer.transform(new DOMSource(doc), new StreamResult(new OutputStreamWriter(out, "UTF-8")));
-            byte[] charData = out.toByteArray();
+            transformer.transform(new DOMSource(doc), new StreamResult(new OutputStreamWriter(out, Charsets.UTF_8)));
+            final byte[] charData = out.toByteArray();
             return new String(charData, "UTF-8");
         } catch (TransformerException | UnsupportedEncodingException e) {
-            String msg = "Error during transformation of Document into String";
-            logger.error(msg, e);
+            final String msg = "Error during transformation of Document into String";
+            LOG.error(msg, e);
             return msg;
         }
     }
 
-    private String toRFC3339(Date d) {
-        return rfc3339.format(d).replaceAll("(\\d\\d)(\\d\\d)$", "$1:$2");
+    /**
+     * Formats data specified by RFC3339.
+     *
+     * @param d
+     *            Date
+     * @return Data specified by RFC3339.
+     */
+    private String toRFC3339(final Date d) {
+        return RFC3339_PATTERN.matcher(rfc3339.format(d)).replaceAll("$1:$2");
     }
 
+    /**
+     * Creates {@link Document} document.
+     * @return {@link Document} document.
+     */
     private Document createDocument() {
-        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
-        Document doc = null;
+        final DocumentBuilder bob;
         try {
-            DocumentBuilder bob = dbf.newDocumentBuilder();
-            doc = bob.newDocument();
-        } catch (ParserConfigurationException e) {
+            bob = DBF.newDocumentBuilder();
+        } catch (final ParserConfigurationException e) {
             return null;
         }
-        return doc;
+        return bob.newDocument();
     }
 
-    private void addValuesToDataChangedNotificationEventElement(Document doc,
-            Element dataChangedNotificationEventElement, DataChangeEvent<InstanceIdentifier, CompositeNode> change) {
-        addValuesFromDataToElement(doc, change.getCreatedConfigurationData(), dataChangedNotificationEventElement, Store.CONFIG, Operation.CREATED);
-        addValuesFromDataToElement(doc, change.getCreatedOperationalData(), dataChangedNotificationEventElement, Store.OPERATION, Operation.CREATED);
-        if (change.getCreatedConfigurationData().isEmpty()) {
-            addValuesFromDataToElement(doc, change.getUpdatedConfigurationData(), dataChangedNotificationEventElement, Store.CONFIG, Operation.UPDATED);
+    /**
+     * Adds values to data changed notification event element.
+     *
+     * @param doc
+     *            {@link Document}
+     * @param dataChangedNotificationEventElement
+     *            {@link Element}
+     * @param change
+     *            {@link DataChangeEvent}
+     */
+    private void addValuesToDataChangedNotificationEventElement(final Document doc,
+            final Element dataChangedNotificationEventElement,
+            final AsyncDataChangeEvent<YangInstanceIdentifier, NormalizedNode<?, ?>> change) {
+        addValuesFromDataToElement(doc, change.getCreatedData().keySet(), dataChangedNotificationEventElement,
+                Operation.CREATED);
+        if (change.getCreatedData().isEmpty()) {
+            addValuesFromDataToElement(doc, change.getUpdatedData().keySet(), dataChangedNotificationEventElement,
+                    Operation.UPDATED);
         }
-        if (change.getCreatedOperationalData().isEmpty()) {
-            addValuesFromDataToElement(doc, change.getUpdatedOperationalData(), dataChangedNotificationEventElement, Store.OPERATION, Operation.UPDATED);
-        }
-        addValuesFromDataToElement(doc, change.getRemovedConfigurationData(), dataChangedNotificationEventElement, Store.CONFIG, Operation.DELETED);
-        addValuesFromDataToElement(doc, change.getRemovedOperationalData(), dataChangedNotificationEventElement, Store.OPERATION, Operation.DELETED);
+        addValuesFromDataToElement(doc, change.getRemovedPaths(), dataChangedNotificationEventElement,
+                Operation.DELETED);
     }
 
-    private void addValuesFromDataToElement(Document doc, Set<InstanceIdentifier> data, Element element, Store store,
-            Operation operation) {
+    /**
+     * Adds values from data to element.
+     *
+     * @param doc
+     *            {@link Document}
+     * @param data
+     *            Set of {@link YangInstanceIdentifier}.
+     * @param element
+     *            {@link Element}
+     * @param store
+     *            {@link Store}
+     * @param operation
+     *            {@link Operation}
+     */
+    private void addValuesFromDataToElement(final Document doc, final Set<YangInstanceIdentifier> data, final Element element,
+            final Operation operation) {
         if (data == null || data.isEmpty()) {
             return;
         }
-        for (InstanceIdentifier path : data) {
-            Node node = createDataChangeEventElement(doc, path, null, store, operation);
+        for (final YangInstanceIdentifier path : data) {
+            final Node node = createDataChangeEventElement(doc, path, null, operation);
             element.appendChild(node);
         }
     }
 
-    private void addValuesFromDataToElement(Document doc, Map<InstanceIdentifier, CompositeNode> data, Element element, Store store,
-            Operation operation) {
+    /**
+     * Adds values from data to element.
+     *
+     * @param doc
+     *            {@link Document}
+     * @param data
+     *            Map of {@link YangInstanceIdentifier} and {@link CompositeNode}.
+     * @param element
+     *            {@link Element}
+     * @param store
+     *            {@link Store}
+     * @param operation
+     *            {@link Operation}
+     */
+    private void addValuesFromDataToElement(final Document doc, final Map<YangInstanceIdentifier, CompositeNode> data, final Element element,
+            final Operation operation) {
         if (data == null || data.isEmpty()) {
             return;
         }
-        for (Entry<InstanceIdentifier, CompositeNode> entry : data.entrySet()) {
-            Node node = createDataChangeEventElement(doc, entry.getKey(), entry.getValue(), store, operation);
+        for (final Entry<YangInstanceIdentifier, CompositeNode> entry : data.entrySet()) {
+            final Node node = createDataChangeEventElement(doc, entry.getKey(), entry.getValue(), operation);
             element.appendChild(node);
         }
     }
 
-    private Node createDataChangeEventElement(Document doc, InstanceIdentifier path, CompositeNode data, Store store,
-            Operation operation) {
-        Element dataChangeEventElement = doc.createElement("data-change-event");
-
-        Element pathElement = doc.createElement("path");
+    /**
+     * Creates changed event element from data.
+     *
+     * @param doc
+     *            {@link Document}
+     * @param path
+     *            Path to data in data store.
+     * @param data
+     *            {@link CompositeNode}
+     * @param store
+     *            {@link Store}
+     * @param operation
+     *            {@link Operation}
+     * @return {@link Node} node represented by changed event element.
+     */
+    private Node createDataChangeEventElement(final Document doc, final YangInstanceIdentifier path, final CompositeNode data,
+            final Operation operation) {
+        final Element dataChangeEventElement = doc.createElement("data-change-event");
+        final Element pathElement = doc.createElement("path");
         addPathAsValueToElement(path, pathElement);
         dataChangeEventElement.appendChild(pathElement);
 
-        Element storeElement = doc.createElement("store");
-        storeElement.setTextContent(store.value);
-        dataChangeEventElement.appendChild(storeElement);
+        // Element storeElement = doc.createElement("store");
+        // storeElement.setTextContent(store.value);
+        // dataChangeEventElement.appendChild(storeElement);
 
-        Element operationElement = doc.createElement("operation");
+        final Element operationElement = doc.createElement("operation");
         operationElement.setTextContent(operation.value);
         dataChangeEventElement.appendChild(operationElement);
 
         if (data != null) {
-            Element dataElement = doc.createElement("data");
-            Node dataAnyXml = translateToXml(path, data);
-            Node adoptedNode = doc.adoptNode(dataAnyXml);
+            final Element dataElement = doc.createElement("data");
+            final Node dataAnyXml = translateToXml(path, data);
+            final Node adoptedNode = doc.adoptNode(dataAnyXml);
             dataElement.appendChild(adoptedNode);
             dataChangeEventElement.appendChild(dataElement);
         }
@@ -259,33 +390,54 @@ public class ListenerAdapter implements DataChangeListener {
         return dataChangeEventElement;
     }
 
-    private Node translateToXml(InstanceIdentifier path, CompositeNode data) {
-        DataNodeContainer schemaNode = ControllerContext.getInstance().getDataNodeContainerFor(path);
+    /**
+     * Translates {@link CompositeNode} data to XML format.
+     *
+     * @param path
+     *            Path to data in data store.
+     * @param data
+     *            {@link CompositeNode}
+     * @return Data in XML format.
+     */
+    private Node translateToXml(final YangInstanceIdentifier path, final CompositeNode data) {
+        final DataNodeContainer schemaNode = ControllerContext.getInstance().getDataNodeContainerFor(path);
         if (schemaNode == null) {
-            logger.info("Path '{}' contains node with unsupported type (supported type is Container or List) or some node was not found.", path);
+            LOG.info(
+                    "Path '{}' contains node with unsupported type (supported type is Container or List) or some node was not found.",
+                    path);
             return null;
         }
         try {
-            Document xml = xmlMapper.write(data, schemaNode);
+            final Document xml = xmlMapper.write(data, schemaNode);
             return xml.getFirstChild();
-        } catch (UnsupportedDataTypeException e) {
-            logger.error("Error occured during translation of notification to XML.", e);
+        } catch (final UnsupportedDataTypeException e) {
+            LOG.error("Error occured during translation of notification to XML.", e);
             return null;
         }
     }
 
-    private void addPathAsValueToElement(InstanceIdentifier path, Element element) {
+    /**
+     * Adds path as value to element.
+     *
+     * @param path
+     *            Path to data in data store.
+     * @param element
+     *            {@link Element}
+     */
+    private void addPathAsValueToElement(final YangInstanceIdentifier path, final Element element) {
         // Map< key = namespace, value = prefix>
-        Map<String, String> prefixes = new HashMap<>();
-        InstanceIdentifier instanceIdentifier = path;
-        StringBuilder textContent = new StringBuilder();
-        for (PathArgument pathArgument : instanceIdentifier.getPath()) {
+        final Map<String, String> prefixes = new HashMap<>();
+        final YangInstanceIdentifier instanceIdentifier = path;
+        final StringBuilder textContent = new StringBuilder();
+
+        // FIXME: BUG-1281: this is duplicated code from yangtools (BUG-1275)
+        for (final PathArgument pathArgument : instanceIdentifier.getPathArguments()) {
             textContent.append("/");
             writeIdentifierWithNamespacePrefix(element, textContent, pathArgument.getNodeType(), prefixes);
             if (pathArgument instanceof NodeIdentifierWithPredicates) {
-                Map<QName, Object> predicates = ((NodeIdentifierWithPredicates) pathArgument).getKeyValues();
-                for (QName keyValue : predicates.keySet()) {
-                    String predicateValue = String.valueOf(predicates.get(keyValue));
+                final Map<QName, Object> predicates = ((NodeIdentifierWithPredicates) pathArgument).getKeyValues();
+                for (final QName keyValue : predicates.keySet()) {
+                    final String predicateValue = String.valueOf(predicates.get(keyValue));
                     textContent.append("[");
                     writeIdentifierWithNamespacePrefix(element, textContent, keyValue, prefixes);
                     textContent.append("='");
@@ -295,7 +447,7 @@ public class ListenerAdapter implements DataChangeListener {
                 }
             } else if (pathArgument instanceof NodeWithValue) {
                 textContent.append("[.='");
-                textContent.append(((NodeWithValue)pathArgument).getValue());
+                textContent.append(((NodeWithValue) pathArgument).getValue());
                 textContent.append("'");
                 textContent.append("]");
             }
@@ -303,18 +455,27 @@ public class ListenerAdapter implements DataChangeListener {
         element.setTextContent(textContent.toString());
     }
 
-    private static void writeIdentifierWithNamespacePrefix(Element element, StringBuilder textContent, QName qName,
-            Map<String, String> prefixes) {
-        String namespace = qName.getNamespace().toString();
+    /**
+     * Writes identifier that consists of prefix and QName.
+     *
+     * @param element
+     *            {@link Element}
+     * @param textContent
+     *            StringBuilder
+     * @param qName
+     *            QName
+     * @param prefixes
+     *            Map of namespaces and prefixes.
+     */
+    private static void writeIdentifierWithNamespacePrefix(final Element element, final StringBuilder textContent,
+            final QName qName, final Map<String, String> prefixes) {
+        final String namespace = qName.getNamespace().toString();
         String prefix = prefixes.get(namespace);
         if (prefix == null) {
-            prefix = qName.getPrefix();
-            if (prefix == null || prefix.isEmpty() || prefixes.containsValue(prefix)) {
-                prefix = generateNewPrefix(prefixes.values());
-            }
+            prefix = generateNewPrefix(prefixes.values());
         }
 
-        element.setAttribute("xmlns:" + prefix, namespace.toString());
+        element.setAttribute("xmlns:" + prefix, namespace);
         textContent.append(prefix);
         prefixes.put(namespace, prefix);
 
@@ -322,13 +483,20 @@ public class ListenerAdapter implements DataChangeListener {
         textContent.append(qName.getLocalName());
     }
 
-    private static String generateNewPrefix(Collection<String> prefixes) {
+    /**
+     * Generates new prefix which consists of four random characters <a-z>.
+     *
+     * @param prefixes
+     *            Collection of prefixes.
+     * @return New prefix which consists of four random characters <a-z>.
+     */
+    private static String generateNewPrefix(final Collection<String> prefixes) {
         StringBuilder result = null;
-        Random random = new Random();
+        final Random random = new Random();
         do {
             result = new StringBuilder();
             for (int i = 0; i < 4; i++) {
-                int randomNumber = 0x61 + (Math.abs(random.nextInt()) % 26);
+                final int randomNumber = 0x61 + (Math.abs(random.nextInt()) % 26);
                 result.append(Character.toChars(randomNumber));
             }
         } while (prefixes.contains(result.toString()));
@@ -336,18 +504,37 @@ public class ListenerAdapter implements DataChangeListener {
         return result.toString();
     }
 
-    public InstanceIdentifier getPath() {
+    /**
+     * Gets path pointed to data in data store.
+     *
+     * @return Path pointed to data in data store.
+     */
+    public YangInstanceIdentifier getPath() {
         return path;
     }
 
-    public void setRegistration(ListenerRegistration<DataChangeListener> registration) {
+    /**
+     * Sets {@link ListenerRegistration} registration.
+     *
+     * @param registration
+     *            ListenerRegistration<DataChangeListener>
+     */
+    public void setRegistration(final ListenerRegistration<DOMDataChangeListener> registration) {
         this.registration = registration;
     }
 
+    /**
+     * Gets the name of the stream.
+     *
+     * @return The name of the stream.
+     */
     public String getStreamName() {
         return streamName;
     }
 
+    /**
+     * Removes all subscribers and unregisters event bus change recorder form event bus.
+     */
     public void close() throws Exception {
         subscribers = new ConcurrentSet<>();
         registration.close();
@@ -355,42 +542,70 @@ public class ListenerAdapter implements DataChangeListener {
         eventBus.unregister(eventBusChangeRecorder);
     }
 
+    /**
+     * Checks if {@link ListenerRegistration} registration exist.
+     *
+     * @return True if exist, false otherwise.
+     */
     public boolean isListening() {
         return registration == null ? false : true;
     }
 
-    public void addSubscriber(Channel subscriber) {
+    /**
+     * Creates event of type {@link EventType#REGISTER}, set {@link Channel} subscriber to the event and post event into
+     * event bus.
+     *
+     * @param subscriber
+     *            Channel
+     */
+    public void addSubscriber(final Channel subscriber) {
         if (!subscriber.isActive()) {
-            logger.debug("Channel is not active between websocket server and subscriber {}"
-                    + subscriber.remoteAddress());
+            LOG.debug("Channel is not active between websocket server and subscriber {}" + subscriber.remoteAddress());
         }
-        Event event = new Event(EventType.REGISTER);
+        final Event event = new Event(EventType.REGISTER);
         event.setSubscriber(subscriber);
         eventBus.post(event);
     }
 
-    public void removeSubscriber(Channel subscriber) {
-        logger.debug("Subscriber {} is removed.", subscriber.remoteAddress());
-        Event event = new Event(EventType.DEREGISTER);
+    /**
+     * Creates event of type {@link EventType#DEREGISTER}, sets {@link Channel} subscriber to the event and posts event
+     * into event bus.
+     *
+     * @param subscriber
+     */
+    public void removeSubscriber(final Channel subscriber) {
+        LOG.debug("Subscriber {} is removed.", subscriber.remoteAddress());
+        final Event event = new Event(EventType.DEREGISTER);
         event.setSubscriber(subscriber);
         eventBus.post(event);
     }
 
+    /**
+     * Checks if exists at least one {@link Channel} subscriber.
+     *
+     * @return True if exist at least one {@link Channel} subscriber, false otherwise.
+     */
     public boolean hasSubscribers() {
         return !subscribers.isEmpty();
     }
 
+    /**
+     * Consists of two types {@link Store#CONFIG} and {@link Store#OPERATION}.
+     */
     private static enum Store {
         CONFIG("config"),
         OPERATION("operation");
 
         private final String value;
 
-        private Store(String value) {
+        private Store(final String value) {
             this.value = value;
         }
     }
 
+    /**
+     * Consists of three types {@link Operation#CREATED}, {@link Operation#UPDATED} and {@link Operation#DELETED}.
+     */
     private static enum Operation {
         CREATED("created"),
         UPDATED("updated"),
@@ -398,7 +613,7 @@ public class ListenerAdapter implements DataChangeListener {
 
         private final String value;
 
-        private Operation(String value) {
+        private Operation(final String value) {
             this.value = value;
         }
     }