gerrit.onap Code Review - sdc.git/blob

   1 /*
   2  * Copyright © 2016-2018 European Support Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package org.openecomp.sdcrests.item.rest.services.catalog.notification;
  18
  19 import java.util.Collection;
  20 import java.util.Objects;
  21 import java.util.concurrent.Callable;
  22 import java.util.concurrent.Executors;
  23 import java.util.concurrent.ScheduledExecutorService;
  24 import java.util.concurrent.TimeUnit;
  25 import java.util.concurrent.atomic.AtomicInteger;
  26 import java.util.function.BiFunction;
  27 import org.openecomp.sdc.logging.api.Logger;
  28 import org.openecomp.sdc.logging.api.LoggerFactory;
  29 import org.openecomp.sdc.logging.api.LoggingContext;
  30 import org.openecomp.sdcrests.item.types.ItemAction;
  31
  32 /**
  33  * Asynchronously runs a notification task.
  34  *
  35  * @author evitaliy
  36  * @since 22 Nov 2018
  37  */
  38 public class AsyncNotifier implements Notifier {
  39
  40     private static final ScheduledExecutorService EXECUTOR_SERVICE = Executors.newScheduledThreadPool(1);
  41
  42     private static final int DEFAULT_NUM_OF_RETRIES = 2;
  43     private static final long DEFAULT_INTERVAL = 5000;
  44
  45     private final BiFunction<Collection<String>, ItemAction, Callable<NextAction>> taskProducer;
  46     private final int numberOfRetries;
  47     private final long retryInterval;
  48
  49
  50     AsyncNotifier(BiFunction<Collection<String>, ItemAction, Callable<NextAction>> taskProducer) {
  51         this(taskProducer, DEFAULT_NUM_OF_RETRIES, DEFAULT_INTERVAL);
  52     }
  53
  54     AsyncNotifier(BiFunction<Collection<String>, ItemAction, Callable<NextAction>> taskProducer, int numOfRetries,
  55             long retryInterval) {
  56         this.taskProducer = taskProducer;
  57         this.numberOfRetries = numOfRetries;
  58         this.retryInterval = retryInterval;
  59     }
  60
  61     @Override
  62     public void execute(Collection<String> itemIds, ItemAction action) {
  63
  64         Callable<AsyncNotifier.NextAction> worker = taskProducer.apply(itemIds, action);
  65
  66         RetryingTask retryingTask = new RetryingTask(worker, numberOfRetries, retryInterval, EXECUTOR_SERVICE);
  67
  68         EXECUTOR_SERVICE.submit(LoggingContext.copyToCallable(retryingTask));
  69     }
  70
  71     public enum NextAction {
  72         RETRY, DONE
  73     }
  74
  75     static class RetryingTask implements Callable<Void> {
  76
  77         private static final Logger LOGGER = LoggerFactory.getLogger(RetryingTask.class);
  78
  79         private final Callable<AsyncNotifier.NextAction> worker;
  80         private final long delay;
  81         private final ScheduledExecutorService scheduler;
  82         private final AtomicInteger retries;
  83
  84         RetryingTask(Callable<AsyncNotifier.NextAction> worker, int numOfRetries, long delay,
  85                 ScheduledExecutorService scheduler) {
  86
  87             this.worker = Objects.requireNonNull(worker);
  88             this.retries = new AtomicInteger(requirePositiveRetries(numOfRetries));
  89             this.delay = requirePositiveDelay(delay);
  90             this.scheduler = Objects.requireNonNull(scheduler);
  91         }
  92
  93         private int requirePositiveRetries(int number) {
  94
  95             if (number < 1) {
  96                 throw new IllegalArgumentException("Number of retries must be positive");
  97             }
  98
  99             return number;
 100         }
 101
 102         private long requirePositiveDelay(long number) {
 103
 104             if (number < 1) {
 105                 throw new IllegalArgumentException("Delay must be positive");
 106             }
 107
 108             return number;
 109         }
 110
 111         @Override
 112         public Void call() throws Exception {
 113
 114             NextAction next = worker.call();
 115             if (next == NextAction.DONE) {
 116                 LOGGER.debug("Task successful: {}. Not going to retry", worker);
 117                 return null;
 118             }
 119
 120             int attempts = retries.decrementAndGet();
 121             if (attempts < 1) {
 122                 LOGGER.warn("Exhausted number of retries for task {}, exiting", worker);
 123                 return null;
 124             }
 125
 126             scheduler.schedule(this, delay, TimeUnit.MILLISECONDS);
 127             return null;
 128         }
 129     }
 130 }