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/*
* Copyright © 2016-2018 European Support Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.openecomp.sdcrests.item.rest.services.catalog.notification;
import java.util.Collection;
import java.util.Objects;
import java.util.concurrent.Callable;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.BiFunction;
import org.openecomp.sdc.logging.api.Logger;
import org.openecomp.sdc.logging.api.LoggerFactory;
import org.openecomp.sdc.logging.api.LoggingContext;
import org.openecomp.sdcrests.item.types.ItemAction;
/**
* Asynchronously runs a notification task.
*
* @author evitaliy
* @since 22 Nov 2018
*/
public class AsyncNotifier implements Notifier {
private static final ScheduledExecutorService EXECUTOR_SERVICE = Executors.newScheduledThreadPool(1);
private static final int DEFAULT_NUM_OF_RETRIES = 2;
private static final long DEFAULT_INTERVAL = 5000;
private final BiFunction<Collection<String>, ItemAction, Callable<NextAction>> taskProducer;
private final int numberOfRetries;
private final long retryInterval;
AsyncNotifier(BiFunction<Collection<String>, ItemAction, Callable<NextAction>> taskProducer) {
this(taskProducer, DEFAULT_NUM_OF_RETRIES, DEFAULT_INTERVAL);
}
AsyncNotifier(BiFunction<Collection<String>, ItemAction, Callable<NextAction>> taskProducer, int numOfRetries, long retryInterval) {
this.taskProducer = taskProducer;
this.numberOfRetries = numOfRetries;
this.retryInterval = retryInterval;
}
@Override
public void execute(Collection<String> itemIds, ItemAction action) {
Callable<AsyncNotifier.NextAction> worker = taskProducer.apply(itemIds, action);
RetryingTask retryingTask = new RetryingTask(worker, numberOfRetries, retryInterval, EXECUTOR_SERVICE);
EXECUTOR_SERVICE.submit(LoggingContext.copyToCallable(retryingTask));
}
public enum NextAction {RETRY, DONE}
static class RetryingTask implements Callable<Void> {
private static final Logger LOGGER = LoggerFactory.getLogger(RetryingTask.class);
private final Callable<AsyncNotifier.NextAction> worker;
private final long delay;
private final ScheduledExecutorService scheduler;
private final AtomicInteger retries;
RetryingTask(Callable<AsyncNotifier.NextAction> worker, int numOfRetries, long delay, ScheduledExecutorService scheduler) {
this.worker = Objects.requireNonNull(worker);
this.retries = new AtomicInteger(requirePositiveRetries(numOfRetries));
this.delay = requirePositiveDelay(delay);
this.scheduler = Objects.requireNonNull(scheduler);
}
private int requirePositiveRetries(int number) {
if (number < 1) {
throw new IllegalArgumentException("Number of retries must be positive");
}
return number;
}
private long requirePositiveDelay(long number) {
if (number < 1) {
throw new IllegalArgumentException("Delay must be positive");
}
return number;
}
@Override
public Void call() throws Exception {
NextAction next = worker.call();
if (next == NextAction.DONE) {
LOGGER.debug("Task successful: {}. Not going to retry", worker);
return null;
}
int attempts = retries.decrementAndGet();
if (attempts < 1) {
LOGGER.warn("Exhausted number of retries for task {}, exiting", worker);
return null;
}
scheduler.schedule(this, delay, TimeUnit.MILLISECONDS);
return null;
}
}
}
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