bgp/rib-spi/src/main/java/org/opendaylight/protocol/bgp/rib/spi/util/ClusterSingletonServiceRegistrationHelper.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
   9 package org.opendaylight.protocol.bgp.rib.spi.util;
  10
  11 import com.google.common.util.concurrent.Uninterruptibles;
  12 import java.util.concurrent.TimeUnit;
  13 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonService;
  14 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceProvider;
  15 import org.opendaylight.mdsal.singleton.common.api.ClusterSingletonServiceRegistration;
  16 import org.slf4j.Logger;
  17 import org.slf4j.LoggerFactory;
  18
  19 /**
  20  * Utility class which provides helper functionality for ClusterSingletonService.
  21  */
  22 public final class ClusterSingletonServiceRegistrationHelper {
  23
  24     private static final Logger LOG = LoggerFactory.getLogger(ClusterSingletonServiceRegistrationHelper.class);
  25     private static final int MAX_REGISTRATION_ATTEMPTS = 10;
  26     private static final int SLEEP_TIME_MILLIS = MAX_REGISTRATION_ATTEMPTS;
  27
  28     private ClusterSingletonServiceRegistrationHelper() {
  29         throw new UnsupportedOperationException();
  30     }
  31
  32     /**
  33      * This helper function wraps
  34      * {@link ClusterSingletonServiceProvider#registerClusterSingletonService(ClusterSingletonService)} in order to
  35      * execute repeated registration attempts while catching RuntimeException. If registration is not successful,
  36      * RuntimeException is re-thrown.
  37      *
  38      * @param singletonProvider Cluster Singleton Service Provider
  39      * @param clusterSingletonService Cluster Singleton Service
  40      * @param maxAttempts             Upper bound for registration retries count.
  41      * @param sleepTime               Sleep time between registration retries in milliseconds.
  42      * @return Registration
  43      */
  44     @SuppressWarnings("checkstyle:IllegalCatch")
  45     public static ClusterSingletonServiceRegistration registerSingletonService(
  46         final ClusterSingletonServiceProvider singletonProvider,
  47         final ClusterSingletonService clusterSingletonService, final int maxAttempts, final int sleepTime) {
  48         int attempts = maxAttempts;
  49         while (true) {
  50             try {
  51                 return singletonProvider.registerClusterSingletonService(clusterSingletonService);
  52             } catch (final RuntimeException e) {
  53                 if (attempts == 0) {
  54                     LOG.error("Giving up after {} registration attempts for service {}.", maxAttempts,
  55                         clusterSingletonService, e);
  56                     throw e;
  57                 }
  58                 attempts--;
  59                 LOG.warn("Failed to register {} service to ClusterSingletonServiceProvider. Try again in {} ms.",
  60                     clusterSingletonService, sleepTime, e);
  61                 Uninterruptibles.sleepUninterruptibly(sleepTime, TimeUnit.MILLISECONDS);
  62             }
  63         }
  64     }
  65
  66     /**
  67      * This helper function wraps
  68      * {@link ClusterSingletonServiceProvider#registerClusterSingletonService(ClusterSingletonService)} in order to
  69      * execute repeated registration attempts while catching RuntimeException. If registration is not successful,
  70      * RuntimeException is re-thrown. 10 registration attempts will be tried with 10 ms pause between each
  71      * other.
  72      *
  73      * @param singletonProvider Cluster Singleton Service Provider
  74      * @param clusterSingletonService Cluster Singleton Service
  75      * @return Registration
  76      */
  77     public static ClusterSingletonServiceRegistration registerSingletonService(final ClusterSingletonServiceProvider
  78         singletonProvider, final ClusterSingletonService clusterSingletonService) {
  79         return ClusterSingletonServiceRegistrationHelper.registerSingletonService(singletonProvider,
  80             clusterSingletonService, MAX_REGISTRATION_ATTEMPTS, SLEEP_TIME_MILLIS);
  81     }
  82 }