content: /*
   * 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 com.alibaba.metrics.instrument;
  
  import com.alibaba.metrics.Counter;
  import com.alibaba.metrics.Histogram;
  import com.alibaba.metrics.Meter;
  import com.alibaba.metrics.MetricRegistry;
  import com.alibaba.metrics.Timer;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Future;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledFuture;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  import java.util.concurrent.atomic.AtomicLong;
  
  /**
   * An {@link ScheduledExecutorService} that monitors the number of tasks submitted, running,
   * completed and also keeps a {@link Timer} for the task duration.
   * <p/>
   * It will register the metrics using the given (or auto-generated) name as classifier, e.g:
   * "your-executor-service.submitted", "your-executor-service.running", etc.
   */
  public class InstrumentedScheduledExecutorService implements ScheduledExecutorService {
      private static final AtomicLong nameCounter = new AtomicLong();
  
      private final ScheduledExecutorService delegate;
  
      private final Meter submitted;
      private final Counter running;
      private final Meter completed;
      private final Timer duration;
  
      private final Meter scheduledOnce;
      private final Meter scheduledRepetitively;
      private final Counter scheduledOverrun;
      private final Histogram percentOfPeriod;
  
      /**
       * Wraps an {@link ScheduledExecutorService} uses an auto-generated default name.
       *
       * @param delegate {@link ScheduledExecutorService} to wrap.
       * @param registry {@link MetricRegistry} that will contain the metrics.
       */
      public InstrumentedScheduledExecutorService(ScheduledExecutorService delegate, MetricRegistry registry) {
          this(delegate, registry, "instrumented-scheduled-executor-service-" + nameCounter.incrementAndGet());
      }
  
      /**
       * Wraps an {@link ScheduledExecutorService} with an explicit name.
       *
       * @param delegate {@link ScheduledExecutorService} to wrap.
       * @param registry {@link MetricRegistry} that will contain the metrics.
       * @param name     name for this executor service.
       */
      public InstrumentedScheduledExecutorService(ScheduledExecutorService delegate, MetricRegistry registry, String name) {
          this.delegate = delegate;
  
          this.submitted = registry.meter(MetricRegistry.name(name, "submitted"));
  
          this.running = registry.counter(MetricRegistry.name(name, "running"));
          this.completed = registry.meter(MetricRegistry.name(name, "completed"));
          this.duration = registry.timer(MetricRegistry.name(name, "duration"));
  
          this.scheduledOnce = registry.meter(MetricRegistry.name(name, "scheduled.once"));
          this.scheduledRepetitively = registry.meter(MetricRegistry.name(name, "scheduled.repetitively"));
          this.scheduledOverrun = registry.counter(MetricRegistry.name(name, "scheduled.overrun"));
          this.percentOfPeriod = registry.histogram(MetricRegistry.name(name, "scheduled.percent-of-period"));
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
          scheduledOnce.mark();
          return delegate.schedule(new InstrumentedRunnable(command), delay, unit);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) {
          scheduledOnce.mark();
          return delegate.schedule(new InstrumentedCallable<V>(callable), delay, unit);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
          scheduledRepetitively.mark();
          return delegate.scheduleAtFixedRate(new InstrumentedPeriodicRunnable(command, period, unit), initialDelay, period, unit);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
          scheduledRepetitively.mark();
          return delegate.scheduleAtFixedRate(new InstrumentedRunnable(command), initialDelay, delay, unit);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void shutdown() {
          delegate.shutdown();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public List<Runnable> shutdownNow() {
          return delegate.shutdownNow();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public boolean isShutdown() {
          return delegate.isShutdown();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public boolean isTerminated() {
          return delegate.isTerminated();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
          return delegate.awaitTermination(timeout, unit);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <T> Future<T> submit(Callable<T> task) {
          submitted.mark();
          return delegate.submit(new InstrumentedCallable<T>(task));
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <T> Future<T> submit(Runnable task, T result) {
          submitted.mark();
          return delegate.submit(new InstrumentedRunnable(task), result);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public Future<?> submit(Runnable task) {
          submitted.mark();
          return delegate.submit(new InstrumentedRunnable(task));
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {
          submitted.mark(tasks.size());
          Collection<? extends Callable<T>> instrumented = instrument(tasks);
          return delegate.invokeAll(instrumented);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException {
          submitted.mark(tasks.size());
          Collection<? extends Callable<T>> instrumented = instrument(tasks);
          return delegate.invokeAll(instrumented, timeout, unit);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {
          submitted.mark(tasks.size());
          Collection<? extends Callable<T>> instrumented = instrument(tasks);
          return delegate.invokeAny(instrumented);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
          submitted.mark(tasks.size());
          Collection<? extends Callable<T>> instrumented = instrument(tasks);
          return delegate.invokeAny(instrumented, timeout, unit);
      }
  
      private <T> Collection<? extends Callable<T>> instrument(Collection<? extends Callable<T>> tasks) {
          final List<InstrumentedCallable<T>> instrumented = new ArrayList<InstrumentedCallable<T>>(tasks.size());
          for (Callable<T> task : tasks) {
              instrumented.add(new InstrumentedCallable(task));
          }
          return instrumented;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void execute(Runnable command) {
          submitted.mark();
          delegate.execute(new InstrumentedRunnable(command));
      }
  
      private class InstrumentedRunnable implements Runnable {
          private final Runnable command;
  
          InstrumentedRunnable(Runnable command) {
              this.command = command;
          }
  
          @Override
          public void run() {
              running.inc();
              final Timer.Context context = duration.time();
              try {
                  command.run();
              } finally {
                  context.stop();
                  running.dec();
                  completed.mark();
              }
          }
      }
  
      private class InstrumentedPeriodicRunnable implements Runnable {
          private final Runnable command;
          private final long periodInNanos;
  
          InstrumentedPeriodicRunnable(Runnable command, long period, TimeUnit unit) {
              this.command = command;
              this.periodInNanos = unit.toNanos(period);
          }
  
          @Override
          public void run() {
              running.inc();
              final Timer.Context context = duration.time();
              try {
                  command.run();
              } finally {
                  final long elapsed = context.stop();
                  running.dec();
                  completed.mark();
                  if (elapsed > periodInNanos) {
                      scheduledOverrun.inc();
                  }
                  percentOfPeriod.update((100L * elapsed) / periodInNanos);
              }
          }
      }
  
      private class InstrumentedCallable<T> implements Callable<T> {
          private final Callable<T> task;
  
          InstrumentedCallable(Callable<T> task) {
              this.task = task;
          }
  
          @Override
          public T call() throws Exception {
              running.inc();
              final Timer.Context context = duration.time();
              try {
                  return task.call();
              } finally {
                  context.stop();
                  running.dec();
                  completed.mark();
              }
          }
      }
  }
  