opendaylight/md-sal/sal-rest-connector/src/main/java/org/opendaylight/controller/sal/streams/listeners/Notificator.java

   1 package org.opendaylight.controller.sal.streams.listeners;
   2
   3 import java.util.Map;
   4 import java.util.concurrent.ConcurrentHashMap;
   5 import java.util.concurrent.locks.Lock;
   6 import java.util.concurrent.locks.ReentrantLock;
   7
   8 import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
   9
  10 /**
  11  * {@link Notificator} is responsible to create, remove and find {@link ListenerAdapter} listener.
  12  */
  13 public class Notificator {
  14
  15         private static Map<String, ListenerAdapter> listenersByStreamName = new ConcurrentHashMap<>();
  16         private static Map<InstanceIdentifier, ListenerAdapter> listenersByInstanceIdentifier = new ConcurrentHashMap<>();
  17         private static final Lock lock = new ReentrantLock();
  18
  19         private Notificator() {
  20         }
  21
  22         /**
  23          * Gets {@link ListenerAdapter} specified by stream name.
  24          *
  25          * @param streamName
  26          *            The name of the stream.
  27          * @return {@link ListenerAdapter} specified by stream name.
  28          */
  29         public static ListenerAdapter getListenerFor(String streamName) {
  30                 return listenersByStreamName.get(streamName);
  31         }
  32
  33         /**
  34          * Gets {@link ListenerAdapter} listener specified by
  35          * {@link InstanceIdentifier} path.
  36          *
  37          * @param path
  38          *            Path to data in data repository.
  39          * @return ListenerAdapter
  40          */
  41         public static ListenerAdapter getListenerFor(InstanceIdentifier path) {
  42                 return listenersByInstanceIdentifier.get(path);
  43         }
  44
  45         /**
  46          * Checks if the listener specified by {@link InstanceIdentifier} path
  47          * exist.
  48          *
  49          * @param path
  50          *            Path to data in data repository.
  51          * @return True if the listener exist, false otherwise.
  52          */
  53         public static boolean existListenerFor(InstanceIdentifier path) {
  54                 return listenersByInstanceIdentifier.containsKey(path);
  55         }
  56
  57         /**
  58          * Creates new {@link ListenerAdapter} listener from
  59          * {@link InstanceIdentifier} path and stream name.
  60          *
  61          * @param path
  62          *            Path to data in data repository.
  63          * @param streamName
  64          *            The name of the stream.
  65          * @return New {@link ListenerAdapter} listener from
  66          *         {@link InstanceIdentifier} path and stream name.
  67          */
  68         public static ListenerAdapter createListener(InstanceIdentifier path,
  69                         String streamName) {
  70                 ListenerAdapter listener = new ListenerAdapter(path, streamName);
  71                 try {
  72                         lock.lock();
  73                         listenersByInstanceIdentifier.put(path, listener);
  74                         listenersByStreamName.put(streamName, listener);
  75                 } finally {
  76                         lock.unlock();
  77                 }
  78                 return listener;
  79         }
  80
  81         /**
  82          * Looks for listener determined by {@link InstanceIdentifier} path and
  83          * removes it.
  84          *
  85          * @param path
  86          *            InstanceIdentifier
  87          */
  88         public static void removeListener(InstanceIdentifier path) {
  89                 ListenerAdapter listener = listenersByInstanceIdentifier.get(path);
  90                 deleteListener(listener);
  91         }
  92
  93         /**
  94          * Creates String representation of stream name from URI. Removes slash from
  95          * URI in start and end position.
  96          *
  97          * @param uri
  98          *            URI for creation stream name.
  99          * @return String representation of stream name.
 100          */
 101         public static String createStreamNameFromUri(String uri) {
 102                 if (uri == null) {
 103                         return null;
 104                 }
 105                 String result = uri;
 106                 if (result.startsWith("/")) {
 107                         result = result.substring(1);
 108                 }
 109                 if (result.endsWith("/")) {
 110                         result = result.substring(0, result.length());
 111                 }
 112                 return result;
 113         }
 114
 115         /**
 116          * Removes all listeners.
 117          */
 118         public static void removeAllListeners() {
 119                 for (ListenerAdapter listener : listenersByInstanceIdentifier.values()) {
 120                         try {
 121                                 listener.close();
 122                         } catch (Exception e) {
 123                         }
 124                 }
 125                 try {
 126                         lock.lock();
 127                         listenersByStreamName = new ConcurrentHashMap<>();
 128                         listenersByInstanceIdentifier = new ConcurrentHashMap<>();
 129                 } finally {
 130                         lock.unlock();
 131                 }
 132         }
 133
 134         /**
 135          * Checks if listener has at least one subscriber. In case it has any, delete
 136          * listener.
 137          *
 138          * @param listener
 139          *            ListenerAdapter
 140          */
 141         public static void removeListenerIfNoSubscriberExists(
 142                         ListenerAdapter listener) {
 143                 if (!listener.hasSubscribers()) {
 144                         deleteListener(listener);
 145                 }
 146         }
 147
 148         /**
 149          * Delete {@link ListenerAdapter} listener specified in parameter.
 150          *
 151          * @param listener
 152          *            ListenerAdapter
 153          */
 154         private static void deleteListener(ListenerAdapter listener) {
 155                 if (listener != null) {
 156                         try {
 157                                 listener.close();
 158                         } catch (Exception e) {
 159                         }
 160                         try {
 161                                 lock.lock();
 162                                 listenersByInstanceIdentifier.remove(listener.getPath());
 163                                 listenersByStreamName.remove(listener.getStreamName());
 164                         } finally {
 165                                 lock.unlock();
 166                         }
 167                 }
 168         }
 169
 170 }