opendaylight/md-sal/samples/clustering-test-app/provider/src/main/java/org/opendaylight/controller/clustering/it/provider/impl/FlappingSingletonService.java

   1 /*
   2  * Copyright (c) 2017 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
   9 package org.opendaylight.controller.clustering.it.provider.impl;
  10
  11 import com.google.common.util.concurrent.Futures;
  12 import com.google.common.util.concurrent.ListenableFuture;
  13 import java.util.concurrent.atomic.AtomicBoolean;
  14 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonService;
  15 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceProvider;
  16 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceRegistration;
  17 import org.opendaylight.mdsal.singleton.common.api.ServiceGroupIdentifier;
  18 import org.slf4j.Logger;
  19 import org.slf4j.LoggerFactory;
  20
  21 public class FlappingSingletonService implements ClusterSingletonService {
  22
  23     private static final Logger LOG = LoggerFactory.getLogger(FlappingSingletonService.class);
  24
  25     private static final ServiceGroupIdentifier SERVICE_GROUP_IDENTIFIER =
  26             ServiceGroupIdentifier.create("flapping-singleton-service");
  27
  28     private final ClusterSingletonServiceProvider singletonServiceProvider;
  29     private final AtomicBoolean active = new AtomicBoolean(true);
  30
  31     private volatile long flapCount = 0;
  32     private volatile ClusterSingletonServiceRegistration registration;
  33
  34     public FlappingSingletonService(final ClusterSingletonServiceProvider singletonServiceProvider) {
  35         LOG.debug("Registering flapping-singleton-service.");
  36
  37         this.singletonServiceProvider = singletonServiceProvider;
  38         registration = singletonServiceProvider.registerClusterSingletonService(this);
  39     }
  40
  41     @Override
  42     public void instantiateServiceInstance() {
  43         LOG.debug("Instantiating flapping-singleton-service.");
  44         try {
  45             registration.close();
  46             registration = null;
  47         } catch (final Exception e) {
  48             LOG.warn("There was a problem closing flapping singleton service.", e);
  49             setInactive();
  50             flapCount = -flapCount;
  51         }
  52     }
  53
  54     @Override
  55     public ListenableFuture<Void> closeServiceInstance() {
  56         LOG.debug("Closing flapping-singleton-service, flapCount: {}", flapCount);
  57
  58         flapCount++;
  59         if (active.get()) {
  60             LOG.debug("Running re-registration");
  61             try {
  62                 registration = singletonServiceProvider.registerClusterSingletonService(this);
  63             } catch (final Exception e) {
  64                 LOG.warn("There was a problem re-registering flapping singleton service.", e);
  65                 setInactive();
  66                 flapCount = -flapCount - 1;
  67             }
  68         }
  69
  70         return Futures.immediateFuture(null);
  71     }
  72
  73     @Override
  74     public ServiceGroupIdentifier getIdentifier() {
  75         return SERVICE_GROUP_IDENTIFIER;
  76     }
  77
  78     public long setInactive() {
  79         LOG.debug("Setting flapping-singleton-service to inactive, flap-count: {}", flapCount);
  80
  81         active.set(false);
  82         return flapCount;
  83     }
  84 }