Class TimingRecorders

java/dagger/producers/monitoring/TimingRecorders.java:32–347

 */
// TODO(beder): Reduce the visibility of this class to package-private.
@Beta
public final class TimingRecorders {
  private static final Logger logger = Logger.getLogger(TimingRecorders.class.getName());

  /**
   * Returns a timing recorder factory that delegates to the given factories, and ensures that any
   * method called on this object, even transitively, does not throw a {@link RuntimeException} or
   * return null.
   *
   * <p>If the delegate recorders throw an {@link Error}, then that will escape this recorder
   * implementation. Errors are treated as unrecoverable conditions, and may cause the entire
   * component's execution to fail.
   */
  public static ProductionComponentTimingRecorder.Factory
      delegatingProductionComponentTimingRecorderFactory(
          Collection<ProductionComponentTimingRecorder.Factory> factories) {
    switch (factories.size()) {
      case 0:
        return noOpProductionComponentTimingRecorderFactory();
      case 1:
        return new NonThrowingProductionComponentTimingRecorder.Factory(
            Iterables.getOnlyElement(factories));
      default:
        return new DelegatingProductionComponentTimingRecorder.Factory(factories);
    }
  }

  /**
   * A component recorder that delegates to a single recorder, and catches and logs all exceptions
   * that the delegate throws.
   */
  private static final class NonThrowingProductionComponentTimingRecorder
      implements ProductionComponentTimingRecorder {
    private final ProductionComponentTimingRecorder delegate;

    NonThrowingProductionComponentTimingRecorder(ProductionComponentTimingRecorder delegate) {
      this.delegate = delegate;
    }

    @Override
    public ProducerTimingRecorder producerTimingRecorderFor(ProducerToken token) {
      try {
        ProducerTimingRecorder recorder = delegate.producerTimingRecorderFor(token);
        return recorder == null
            ? ProducerTimingRecorder.noOp()
            : new NonThrowingProducerTimingRecorder(recorder);
      } catch (RuntimeException e) {
        logProducerTimingRecorderForException(e, delegate, token);
        return ProducerTimingRecorder.noOp();
      }
    }

    static final class Factory implements ProductionComponentTimingRecorder.Factory {
      private final ProductionComponentTimingRecorder.Factory delegate;

      Factory(ProductionComponentTimingRecorder.Factory delegate) {
        this.delegate = delegate;
      }