}
    }

    /**
     * Stores a failure URL with error information for later analysis.
     *
     * @param crawlerContext the crawler context
     * @param urlQueue the URL queue containing the failed URL
     * @param errorName the name/type of the error
     * @param e the throwable that caused the failure
     * @return the stored FailureUrl entity
     */

They tend to require more complex configurations, a message/job queue manager, like RabbitMQ or Redis, but they allow you to run background tasks in multiple processes, and especially, in multiple servers.

import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Optional;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.OptionalLong;
import java.util.Queue;
import java.util.Random;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.UUID;
import java.util.concurrent.BlockingDeque;

a.ActiveXObject("Microsoft.XMLHTTP")}return function(){return b}}(),f=function(a,b){var c=e();c&&(c.open("GET",a,!0),c.onreadystatechange=function(){4!==c.readyState||200!==c.status&&304!==c.status||b(c.responseText)},4!==c.readyState&&c.send(null))};if(c.ajax=f,c.queue=d,c.regex={media:/@media[^\{]+\{([^\{\}]*\{[^\}\{]*\})+/gi,keyframes:/@(?:\-(?:o|moz|webkit)\-)?keyframes[^\{]+\{(?:[^\{\}]*\{[^\}\{]*\})+[^\}]*\}/gi,urls:/(url\()['"]?([^\/\)'"][^:\)'"]+)['"]?(\))/g,findStyles:/@media *([^\{]+)\{([\S\s]+?)$/,only...

   * is used to calculate this value. It also doesn't include any bytes buffered by the operating
   * system or network intermediaries. This method returns 0 if no messages are waiting in the
   * queue. If may return a nonzero value after the web socket has been canceled; this indicates
   * that enqueued messages were not transmitted.
   */
  fun queueSize(): Long

  /**

## Conflict Resolution

Conflicts in an open source project can take many forms, from someone having a bad day and using harsh and hurtful language in the issue queue, to more serious instances such as sexist/racist statements or threats of violence, and everything in between.

If the behavior is threatening or harassing, or for other reasons requires immediate escalation, please see below.

    // contract.
    // This is somewhat annoying, but turns out to be very fast in practice. Alternatively, we could
    // drop the contract on the method that enforces this queue like behavior since depending on it
    // is likely to be a bug anyway.

    // N.B. All writes to the list and the next pointers must have happened before the above

    Set<Object> actualValues = ImmutableSet.copyOf(map.values());
    assertEquals(expectedValues, actualValues);
  }

  /** Lookups on the map view shouldn't impact the recency queue. */
  public void testAsMapRecency() {
    CacheBuilder<Object, Object> builder =
        createCacheBuilder().concurrencyLevel(1).maximumSize(SMALL_MAX_SIZE);

                return true;
            }
        }
        return false;
    }

    /**
     * Processes the result data and stores it along with child URLs.
     *
     * @param urlQueue the URL queue entry
     * @param responseData the response data
     * @param resultData the result data
     */
    protected void processResult(final UrlQueue<?> urlQueue, final ResponseData responseData, final ResultData resultData) {

 * executor, it should be able to run [the configured maximum][maxRequests] number of calls
 * concurrently.
 */
class Dispatcher() {
  /**
   * The maximum number of requests to execute concurrently. Above this requests queue in memory,
   * waiting for the running calls to complete.
   *
   * If more than [maxRequests] requests are in flight when this is invoked, those requests will
   * remain in flight.
   */
  @get:Synchronized