| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 backtype.storm.windowing; |
| |
| import backtype.storm.topology.FailedException; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ScheduledFuture; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * Invokes {@link TriggerHandler#onTrigger()} after the duration. |
| */ |
| public class TimeTriggerPolicy<T> implements TriggerPolicy<T> { |
| private static final Logger LOG = LoggerFactory.getLogger(TimeTriggerPolicy.class); |
| |
| private long duration; |
| private final TriggerHandler handler; |
| private final ScheduledExecutorService executor; |
| private final ScheduledFuture<?> executorFuture; |
| |
| public TimeTriggerPolicy(long millis, TriggerHandler handler) { |
| this.duration = millis; |
| this.handler = handler; |
| this.executor = Executors.newSingleThreadScheduledExecutor(); |
| this.executorFuture = executor.scheduleAtFixedRate(newTriggerTask(), duration, duration, TimeUnit.MILLISECONDS); |
| } |
| |
| @Override |
| public void track(Event<T> event) { |
| checkFailures(); |
| } |
| |
| @Override |
| public void reset() { |
| checkFailures(); |
| } |
| |
| @Override |
| public void shutdown() { |
| executor.shutdown(); |
| try { |
| if (!executor.awaitTermination(2, TimeUnit.SECONDS)) { |
| executor.shutdownNow(); |
| } |
| } catch (InterruptedException ie) { |
| executor.shutdownNow(); |
| Thread.currentThread().interrupt(); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return "TimeTriggerPolicy{" + |
| "duration=" + duration + |
| '}'; |
| } |
| |
| /* |
| * Check for uncaught exceptions during the execution |
| * of the trigger and fail fast. |
| * The uncaught exceptions will be wrapped in |
| * ExecutionException and thrown when future.get() is invoked. |
| */ |
| private void checkFailures() { |
| if (executorFuture.isDone()) { |
| try { |
| executorFuture.get(); |
| } catch (InterruptedException ex) { |
| LOG.error("Got exception ", ex); |
| throw new FailedException(ex); |
| } catch (ExecutionException ex) { |
| LOG.error("Got exception ", ex); |
| throw new FailedException(ex.getCause()); |
| } |
| } |
| } |
| |
| private Runnable newTriggerTask() { |
| return new Runnable() { |
| @Override |
| public void run() { |
| try { |
| handler.onTrigger(); |
| } catch (Throwable th) { |
| LOG.error("handler.onTrigger failed ", th); |
| /* |
| * propagate it so that task gets canceled and the exception |
| * can be retrieved from executorFuture.get() |
| */ |
| throw th; |
| } |
| } |
| }; |
| } |
| } |