monitor.leave();
          }
        });
    awaitUninterruptibly(enteredLatch);
  }

  @CanIgnoreReturnValue
  static Thread startThread(Runnable runnable) {
    Thread thread = new Thread(runnable);
    thread.setDaemon(true);
    thread.start();
    return thread;
  }

  /**
   * Generates a test case verifying that calling any enterXxx, tryEnterXxx, or waitForXxx method

            monitor.leave();
          }
        });
    awaitUninterruptibly(enteredLatch);
  }

  @CanIgnoreReturnValue
  static Thread startThread(Runnable runnable) {
    Thread thread = new Thread(runnable);
    thread.setDaemon(true);
    thread.start();
    return thread;
  }

  /**
   * Generates a test case verifying that calling any enterXxx, tryEnterXxx, or waitForXxx method

  ├─ ExecutionTimeoutException
  ├─ MimeTypeException
  ├─ MultipleCrawlingAccessException
  ├─ RobotsTxtException
  └─ SitemapsException
```

### Thread-Local Storage

Use `CrawlingParameterUtil` to set/get `CrawlerContext` and `UrlQueue` in worker threads. Always clear in finally block with `CrawlingParameterUtil.clearAll()`.

### Resource Cleanup Pattern

     * as well as to handle state changes in a thread-safe manner. The current state of the future
     * is held in the Sync state, and the lock is released whenever the state changes to {@link
     * #COMPLETED}, {@link #CANCELLED}, or {@link #INTERRUPTED}
     *
     * <p>To avoid races between threads doing release and acquire, we transition to the final state

                    throw new IllegalArgumentException("Invalid threads core multiplier value: '" + threadConfiguration
                            + "'. Value must be positive.");
                }

                int procs = Runtime.getRuntime().availableProcessors();
                int threads = (int) (coreMultiplier * procs);
                return threads == 0 ? 1 : threads;
            } else {

# Side Public License, v 1.

# For third-party dependencies, please put signatures in third-party.txt instead of here.

@defaultMessage spawns threads with vague names; use a custom thread factory and name threads so that you can tell (by its name) which executor it is associated with

java.util.concurrent.Executors#newFixedThreadPool(int)
java.util.concurrent.Executors#newSingleThreadExecutor()

                } finally {
                    endLatch.countDown();
                }
            });
        }

        // Start all threads
        startLatch.countDown();

        // Wait for completion
        assertTrue(endLatch.await(30, TimeUnit.SECONDS), "All threads should complete");
        executor.shutdown();

        // Then - All operations should succeed

        protected String propertiesPath;

        /**
         * Number of threads to use for thumbnail generation.
         */
        @Option(name = "-t", aliases = "--numOfThreads", metaVar = "numOfThreads", usage = "The number of threads")
        protected int numOfThreads = 1;

        /**
         * Whether to run in cleanup mode to remove old thumbnails.
         */

   * calling thread. Tasks are run to completion before a {@code Future} is returned to the caller
   * (unless the executor has been shutdown).
   *
   * <p>The returned executor is backed by the executor returned by {@link
   * MoreExecutors#newDirectExecutorService} and subject to the same constraints.
   *
   * <p>Although all tasks are immediately executed in the thread that submitted the task, this

                // Explicitly yield to increase the probability of a pathological scheduling.
                Thread.yield();
                return new Schedule(0, SECONDS);
              }
            };
          }
        };
    service.useBarriers = false;
    service.startAsync().awaitRunning();
    Thread.sleep(50);
    service.useBarriers = true;
    service.firstBarrier.await();