* Cache#invalidate invalidations}.
     */
    void recordEviction();

    /**
     * Returns a snapshot of this counter's values. Note that this may be an inconsistent view, as
     * it may be interleaved with update operations.
     */
    CacheStats snapshot();
  }

  /**

    queue.addListener(listener, directExecutor());

    Multiset<Object> counters = ConcurrentHashMultiset.create();
    queue.enqueue(incrementingEvent(counters, listener, 1));
    queue.enqueue(incrementingEvent(counters, listener, 2));
    queue.enqueue(incrementingEvent(counters, listener, 3));
    queue.enqueue(incrementingEvent(counters, listener, 4));
    assertEquals(0, counters.size());
    queue.dispatch();

    queue.addListener(listener, directExecutor());

    Multiset<Object> counters = ConcurrentHashMultiset.create();
    queue.enqueue(incrementingEvent(counters, listener, 1));
    queue.enqueue(incrementingEvent(counters, listener, 2));
    queue.enqueue(incrementingEvent(counters, listener, 3));
    queue.enqueue(incrementingEvent(counters, listener, 4));
    assertEquals(0, counters.size());
    queue.dispatch();

    }

    @Override
    public int compareTo(CountsHashCodeAndEquals o) {
      onCompareTo.run();
      return delegateString.compareTo(o.delegateString);
    }
  }

  /** A holder of counters for calls to hashCode, equals, and compareTo. */
  private static final class CallsCounter {
    long hashCode;
    long equals;
    long compareTo;

    long total() {
      return hashCode + equals + compareTo;

   *
   * <p>Usage example:
   *
   * {@snippet :
   * // Falling back to a zero counter in case an exception happens when processing the RPC to fetch
   * // counters.
   * ListenableFuture<Integer> faultTolerantFuture =
   *     fetchCounters().catching(FetchException.class, x -> 0, directExecutor());
   * }
   *

- **Template Method**: `AbstractCrawlerClient`, `AbstractExtractor` - common logic with overrides
- **DI**: LastaFlute container with `@Resource` and XML config

### Core Principles

**Thread Safety**: `AtomicLong` for counters, `volatile` for status flags, synchronized blocks, thread-local storage via `CrawlingParameterUtil`

              ++counts;
            }
          }
        }
        if (done) {
          break;
        }
      }
    }
  }

  /**
   * Multiple threads using same array of counters successfully update a number of times equal to
   * total count
   */
  public void testCountingInMultipleThreads() throws InterruptedException {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);

              ++counts;
            }
          }
        }
        if (done) {
          break;
        }
      }
    }
  }

  /**
   * Multiple threads using same array of counters successfully update a number of times equal to
   * total count
   */
  public void testCountingInMultipleThreads() throws InterruptedException {
    AtomicDoubleArray aa = new AtomicDoubleArray(SIZE);

   * <p>Usage example:
   *
   * {@snippet :
   * ListenableFuture<Integer> fetchCounterFuture = ...;
   *
   * // Falling back to a zero counter in case an exception happens when
   * // processing the RPC to fetch counters.
   * ListenableFuture<Integer> faultTolerantFuture = Futures.catching(
   *     fetchCounterFuture, FetchException.class, x -> 0, directExecutor());
   * }
   *

Then the cashier 💁 says "I'm finished with doing the burgers" by putting your number on the counter's display, but you don't jump like crazy immediately when the displayed number changes to your turn number. You know no one will steal your burgers because you have the number of your turn, and they have theirs.