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.Set;
   5 import java.util.concurrent.ConcurrentHashMap;
   6 import java.util.concurrent.locks.Lock;
   7 import java.util.concurrent.locks.ReentrantLock;
   8
   9 import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
  10
  11 /**
  12  * {@link Notificator} is responsible to create, remove and find {@link ListenerAdapter} listener.
  13  */
  14 public class Notificator {
  15
  16     private static Map<String, ListenerAdapter> listenersByStreamName = new ConcurrentHashMap<>();
  17         private static Map<InstanceIdentifier, ListenerAdapter> listenersByInstanceIdentifier = new ConcurrentHashMap<>();
  18         private static final Lock lock = new ReentrantLock();
  19
  20         private Notificator() {
  21         }
  22
  23     /**
  24      * Returns list of all stream names
  25      */
  26     public static Set<String> getStreamNames() {
  27         return listenersByStreamName.keySet();
  28     }
  29
  30
  31         /**
  32          * Gets {@link ListenerAdapter} specified by stream name.
  33          *
  34          * @param streamName
  35          *            The name of the stream.
  36          * @return {@link ListenerAdapter} specified by stream name.
  37          */
  38         public static ListenerAdapter getListenerFor(String streamName) {
  39                 return listenersByStreamName.get(streamName);
  40         }
  41
  42         /**
  43          * Gets {@link ListenerAdapter} listener specified by
  44          * {@link InstanceIdentifier} path.
  45          *
  46          * @param path
  47          *            Path to data in data repository.
  48          * @return ListenerAdapter
  49          */
  50         public static ListenerAdapter getListenerFor(InstanceIdentifier path) {
  51                 return listenersByInstanceIdentifier.get(path);
  52         }
  53
  54         /**
  55          * Checks if the listener specified by {@link InstanceIdentifier} path
  56          * exist.
  57          *
  58          * @param path
  59          *            Path to data in data repository.
  60          * @return True if the listener exist, false otherwise.
  61          */
  62         public static boolean existListenerFor(InstanceIdentifier path) {
  63                 return listenersByInstanceIdentifier.containsKey(path);
  64         }
  65
  66         /**
  67          * Creates new {@link ListenerAdapter} listener from
  68          * {@link InstanceIdentifier} path and stream name.
  69          *
  70          * @param path
  71          *            Path to data in data repository.
  72          * @param streamName
  73          *            The name of the stream.
  74          * @return New {@link ListenerAdapter} listener from
  75          *         {@link InstanceIdentifier} path and stream name.
  76          */
  77         public static ListenerAdapter createListener(InstanceIdentifier path,
  78                         String streamName) {
  79                 ListenerAdapter listener = new ListenerAdapter(path, streamName);
  80                 try {
  81                         lock.lock();
  82                         listenersByInstanceIdentifier.put(path, listener);
  83                         listenersByStreamName.put(streamName, listener);
  84                 } finally {
  85                         lock.unlock();
  86                 }
  87                 return listener;
  88         }
  89
  90         /**
  91          * Looks for listener determined by {@link InstanceIdentifier} path and
  92          * removes it.
  93          *
  94          * @param path
  95          *            InstanceIdentifier
  96          */
  97         public static void removeListener(InstanceIdentifier path) {
  98                 ListenerAdapter listener = listenersByInstanceIdentifier.get(path);
  99                 deleteListener(listener);
 100         }
 101
 102         /**
 103          * Creates String representation of stream name from URI. Removes slash from
 104          * URI in start and end position.
 105          *
 106          * @param uri
 107          *            URI for creation stream name.
 108          * @return String representation of stream name.
 109          */
 110         public static String createStreamNameFromUri(String uri) {
 111                 if (uri == null) {
 112                         return null;
 113                 }
 114                 String result = uri;
 115                 if (result.startsWith("/")) {
 116                         result = result.substring(1);
 117                 }
 118                 if (result.endsWith("/")) {
 119                         result = result.substring(0, result.length());
 120                 }
 121                 return result;
 122         }
 123
 124         /**
 125          * Removes all listeners.
 126          */
 127         public static void removeAllListeners() {
 128                 for (ListenerAdapter listener : listenersByInstanceIdentifier.values()) {
 129                         try {
 130                                 listener.close();
 131                         } catch (Exception e) {
 132                         }
 133                 }
 134                 try {
 135                         lock.lock();
 136                         listenersByStreamName = new ConcurrentHashMap<>();
 137                         listenersByInstanceIdentifier = new ConcurrentHashMap<>();
 138                 } finally {
 139                         lock.unlock();
 140                 }
 141         }
 142
 143         /**
 144          * Checks if listener has at least one subscriber. In case it doesn't have any, delete
 145          * listener.
 146          *
 147          * @param listener
 148          *            ListenerAdapter
 149          */
 150         public static void removeListenerIfNoSubscriberExists(
 151                         ListenerAdapter listener) {
 152                 if (!listener.hasSubscribers()) {
 153                         deleteListener(listener);
 154                 }
 155         }
 156
 157         /**
 158          * Delete {@link ListenerAdapter} listener specified in parameter.
 159          *
 160          * @param listener
 161          *            ListenerAdapter
 162          */
 163         private static void deleteListener(ListenerAdapter listener) {
 164                 if (listener != null) {
 165                         try {
 166                                 listener.close();
 167                         } catch (Exception e) {
 168                         }
 169                         try {
 170                                 lock.lock();
 171                                 listenersByInstanceIdentifier.remove(listener.getPath());
 172                                 listenersByStreamName.remove(listener.getStreamName());
 173                         } finally {
 174                                 lock.unlock();
 175                         }
 176                 }
 177         }
 178
 179 }