restconf/restconf-nb-rfc8040/src/main/java/org/opendaylight/restconf/nb/rfc8040/streams/listeners/NotificationListenerAdapter.java

   1 /*
   2  * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.restconf.nb.rfc8040.streams.listeners;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Preconditions;
  12 import com.google.gson.JsonObject;
  13 import com.google.gson.JsonParser;
  14 import java.io.IOException;
  15 import java.io.StringWriter;
  16 import java.io.Writer;
  17 import java.time.Instant;
  18 import java.util.Collection;
  19 import javax.xml.stream.XMLStreamException;
  20 import javax.xml.transform.dom.DOMResult;
  21 import org.opendaylight.controller.md.sal.dom.api.DOMNotification;
  22 import org.opendaylight.controller.md.sal.dom.api.DOMNotificationListener;
  23 import org.opendaylight.restconf.common.errors.RestconfDocumentedException;
  24 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
  25 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  26 import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
  27 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  28 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
  29 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter;
  30 import org.opendaylight.yangtools.yang.data.codec.gson.JSONCodecFactory;
  31 import org.opendaylight.yangtools.yang.data.codec.gson.JSONNormalizedNodeStreamWriter;
  32 import org.opendaylight.yangtools.yang.data.codec.gson.JsonWriterFactory;
  33 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  34 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37 import org.w3c.dom.Document;
  38 import org.w3c.dom.Element;
  39 import org.w3c.dom.Node;
  40
  41 /**
  42  * {@link NotificationListenerAdapter} is responsible to track events on
  43  * notifications.
  44  *
  45  */
  46 public class NotificationListenerAdapter extends AbstractCommonSubscriber implements DOMNotificationListener {
  47
  48     private static final Logger LOG = LoggerFactory.getLogger(NotificationListenerAdapter.class);
  49
  50     private final String streamName;
  51     private final SchemaPath path;
  52     private final String outputType;
  53
  54     private SchemaContext schemaContext;
  55     private DOMNotification notification;
  56
  57     /**
  58      * Set path of listener and stream name, register event bus.
  59      *
  60      * @param path
  61      *             path of notification
  62      * @param streamName
  63      *             stream name of listener
  64      * @param outputType
  65      *             type of output on notification (JSON, XML)
  66      */
  67     NotificationListenerAdapter(final SchemaPath path, final String streamName, final String outputType) {
  68         register(this);
  69         setLocalNameOfPath(path.getLastComponent().getLocalName());
  70
  71         this.outputType = Preconditions.checkNotNull(outputType);
  72         this.path = Preconditions.checkNotNull(path);
  73         Preconditions.checkArgument(streamName != null && !streamName.isEmpty());
  74         this.streamName = streamName;
  75     }
  76
  77     /**
  78      * Get outputType of listener.
  79      *
  80      * @return the outputType
  81      */
  82     @Override
  83     public String getOutputType() {
  84         return this.outputType;
  85     }
  86
  87     @Override
  88     public void onNotification(final DOMNotification notification) {
  89         this.schemaContext = schemaHandler.get();
  90         this.notification = notification;
  91
  92         final String xml = prepareXml();
  93         if (checkQueryParams(xml, this)) {
  94             prepareAndPostData(xml);
  95         }
  96     }
  97
  98     /**
  99      * Get stream name of this listener.
 100      *
 101      * @return {@link String}
 102      */
 103     @Override
 104     public String getStreamName() {
 105         return this.streamName;
 106     }
 107
 108     /**
 109      * Get schema path of notification.
 110      *
 111      * @return {@link SchemaPath}
 112      */
 113     public SchemaPath getSchemaPath() {
 114         return this.path;
 115     }
 116
 117     /**
 118      * Prepare data of notification and data to client.
 119      *
 120      * @param xml   data
 121      */
 122     private void prepareAndPostData(final String xml) {
 123         final Event event = new Event(EventType.NOTIFY);
 124         if (this.outputType.equals("JSON")) {
 125             event.setData(prepareJson());
 126         } else {
 127             event.setData(xml);
 128         }
 129         post(event);
 130     }
 131
 132     /**
 133      * Prepare json from notification data.
 134      *
 135      * @return json as {@link String}
 136      */
 137     @VisibleForTesting
 138     String prepareJson() {
 139         final JsonParser jsonParser = new JsonParser();
 140         final JsonObject json = new JsonObject();
 141         json.add("ietf-restconf:notification", jsonParser.parse(writeBodyToString()));
 142         json.addProperty("event-time", ListenerAdapter.toRFC3339(Instant.now()));
 143         return json.toString();
 144     }
 145
 146     @VisibleForTesting
 147     void setNotification(final DOMNotification notification) {
 148         this.notification = Preconditions.checkNotNull(notification);
 149     }
 150
 151     @VisibleForTesting
 152     void setSchemaContext(final SchemaContext schemaContext) {
 153         this.schemaContext = Preconditions.checkNotNull(schemaContext);
 154     }
 155
 156     private String writeBodyToString() {
 157         final Writer writer = new StringWriter();
 158         final NormalizedNodeStreamWriter jsonStream =
 159                 JSONNormalizedNodeStreamWriter.createExclusiveWriter(JSONCodecFactory.getShared(this.schemaContext),
 160                         this.notification.getType(), null, JsonWriterFactory.createJsonWriter(writer));
 161         final NormalizedNodeWriter nodeWriter = NormalizedNodeWriter.forStreamWriter(jsonStream);
 162         try {
 163             nodeWriter.write(this.notification.getBody());
 164             nodeWriter.close();
 165         } catch (final IOException e) {
 166             throw new RestconfDocumentedException("Problem while writing body of notification to JSON. ", e);
 167         }
 168         return writer.toString();
 169     }
 170
 171     private String prepareXml() {
 172         final Document doc = createDocument();
 173         final Element notificationElement = basePartDoc(doc);
 174
 175         final Element notificationEventElement = doc.createElementNS(
 176                 "urn:opendaylight:params:xml:ns:yang:controller:md:sal:remote", "create-notification-stream");
 177         addValuesToNotificationEventElement(doc, notificationEventElement, this.notification, this.schemaContext);
 178         notificationElement.appendChild(notificationEventElement);
 179
 180         return transformDoc(doc);
 181     }
 182
 183     private void addValuesToNotificationEventElement(final Document doc, final Element element,
 184             final DOMNotification notification, final SchemaContext schemaContext) {
 185         if (notification == null) {
 186             return;
 187         }
 188
 189         final NormalizedNode<NodeIdentifier, Collection<DataContainerChild<? extends PathArgument, ?>>> body =
 190                 notification.getBody();
 191         try {
 192
 193             final DOMResult domResult = writeNormalizedNode(body, schemaContext, this.path);
 194             final Node result = doc.importNode(domResult.getNode().getFirstChild(), true);
 195             final Element dataElement = doc.createElement("notification");
 196             dataElement.appendChild(result);
 197             element.appendChild(dataElement);
 198         } catch (final IOException e) {
 199             LOG.error("Error in writer ", e);
 200         } catch (final XMLStreamException e) {
 201             LOG.error("Error processing stream", e);
 202         }
 203     }
 204 }