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

   1 /*
   2  * Copyright (c) 2014 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.controller.sal.streams.listeners;
   9
  10 import java.util.Map;
  11 import java.util.Set;
  12 import java.util.concurrent.ConcurrentHashMap;
  13 import java.util.concurrent.locks.Lock;
  14 import java.util.concurrent.locks.ReentrantLock;
  15
  16 import org.opendaylight.yangtools.yang.data.api.InstanceIdentifier;
  17
  18 /**
  19  * {@link Notificator} is responsible to create, remove and find {@link ListenerAdapter} listener.
  20  */
  21 public class Notificator {
  22
  23     private static Map<String, ListenerAdapter> listenersByStreamName = new ConcurrentHashMap<>();
  24         private static Map<InstanceIdentifier, ListenerAdapter> listenersByInstanceIdentifier = new ConcurrentHashMap<>();
  25         private static final Lock lock = new ReentrantLock();
  26
  27         private Notificator() {
  28         }
  29
  30     /**
  31      * Returns list of all stream names
  32      */
  33     public static Set<String> getStreamNames() {
  34         return listenersByStreamName.keySet();
  35     }
  36
  37
  38         /**
  39          * Gets {@link ListenerAdapter} specified by stream name.
  40          *
  41          * @param streamName
  42          *            The name of the stream.
  43          * @return {@link ListenerAdapter} specified by stream name.
  44          */
  45         public static ListenerAdapter getListenerFor(String streamName) {
  46                 return listenersByStreamName.get(streamName);
  47         }
  48
  49         /**
  50          * Gets {@link ListenerAdapter} listener specified by
  51          * {@link InstanceIdentifier} path.
  52          *
  53          * @param path
  54          *            Path to data in data repository.
  55          * @return ListenerAdapter
  56          */
  57         public static ListenerAdapter getListenerFor(InstanceIdentifier path) {
  58                 return listenersByInstanceIdentifier.get(path);
  59         }
  60
  61         /**
  62          * Checks if the listener specified by {@link InstanceIdentifier} path
  63          * exist.
  64          *
  65          * @param path
  66          *            Path to data in data repository.
  67          * @return True if the listener exist, false otherwise.
  68          */
  69         public static boolean existListenerFor(InstanceIdentifier path) {
  70                 return listenersByInstanceIdentifier.containsKey(path);
  71         }
  72
  73         /**
  74          * Creates new {@link ListenerAdapter} listener from
  75          * {@link InstanceIdentifier} path and stream name.
  76          *
  77          * @param path
  78          *            Path to data in data repository.
  79          * @param streamName
  80          *            The name of the stream.
  81          * @return New {@link ListenerAdapter} listener from
  82          *         {@link InstanceIdentifier} path and stream name.
  83          */
  84         public static ListenerAdapter createListener(InstanceIdentifier path,
  85                         String streamName) {
  86                 ListenerAdapter listener = new ListenerAdapter(path, streamName);
  87                 try {
  88                         lock.lock();
  89                         listenersByInstanceIdentifier.put(path, listener);
  90                         listenersByStreamName.put(streamName, listener);
  91                 } finally {
  92                         lock.unlock();
  93                 }
  94                 return listener;
  95         }
  96
  97         /**
  98          * Looks for listener determined by {@link InstanceIdentifier} path and
  99          * removes it.
 100          *
 101          * @param path
 102          *            InstanceIdentifier
 103          */
 104         public static void removeListener(InstanceIdentifier path) {
 105                 ListenerAdapter listener = listenersByInstanceIdentifier.get(path);
 106                 deleteListener(listener);
 107         }
 108
 109         /**
 110          * Creates String representation of stream name from URI. Removes slash from
 111          * URI in start and end position.
 112          *
 113          * @param uri
 114          *            URI for creation stream name.
 115          * @return String representation of stream name.
 116          */
 117         public static String createStreamNameFromUri(String uri) {
 118                 if (uri == null) {
 119                         return null;
 120                 }
 121                 String result = uri;
 122                 if (result.startsWith("/")) {
 123                         result = result.substring(1);
 124                 }
 125                 if (result.endsWith("/")) {
 126                         result = result.substring(0, result.length());
 127                 }
 128                 return result;
 129         }
 130
 131         /**
 132          * Removes all listeners.
 133          */
 134         public static void removeAllListeners() {
 135                 for (ListenerAdapter listener : listenersByInstanceIdentifier.values()) {
 136                         try {
 137                                 listener.close();
 138                         } catch (Exception e) {
 139                         }
 140                 }
 141                 try {
 142                         lock.lock();
 143                         listenersByStreamName = new ConcurrentHashMap<>();
 144                         listenersByInstanceIdentifier = new ConcurrentHashMap<>();
 145                 } finally {
 146                         lock.unlock();
 147                 }
 148         }
 149
 150         /**
 151          * Checks if listener has at least one subscriber. In case it doesn't have any, delete
 152          * listener.
 153          *
 154          * @param listener
 155          *            ListenerAdapter
 156          */
 157         public static void removeListenerIfNoSubscriberExists(
 158                         ListenerAdapter listener) {
 159                 if (!listener.hasSubscribers()) {
 160                         deleteListener(listener);
 161                 }
 162         }
 163
 164         /**
 165          * Delete {@link ListenerAdapter} listener specified in parameter.
 166          *
 167          * @param listener
 168          *            ListenerAdapter
 169          */
 170         private static void deleteListener(ListenerAdapter listener) {
 171                 if (listener != null) {
 172                         try {
 173                                 listener.close();
 174                         } catch (Exception e) {
 175                         }
 176                         try {
 177                                 lock.lock();
 178                                 listenersByInstanceIdentifier.remove(listener.getPath());
 179                                 listenersByStreamName.remove(listener.getStreamName());
 180                         } finally {
 181                                 lock.unlock();
 182                         }
 183                 }
 184         }
 185
 186 }