if (logger.isDebugEnabled()) {
                    logger.debug("Failed to select a job by {}", id, e);
                }
                lastException = e;
                ThreadUtil.sleep(RandomUtils.nextLong(500, 5000));
            }
        }
        logger.warn("Failed to select a job by {}", id, lastException);
        return OptionalEntity.empty();
    }

	return=$?
	if [ $return -eq 0 ]; then
		i=0
		timeout=10
		# Wait for the process to be properly started before exiting
		until { kill -0 `cat "$PID_FILE"`; } >/dev/null 2>&1
		do
			sleep 1
			i=$(($i + 1))
			if [ $i -gt $timeout ]; then
				log_end_msg 1
				exit 1
			fi
		done
	fi
	log_end_msg $return
	exit $return
	;;		
  stop)
	log_daemon_msg "Stopping $DESC"

            ThreadUtil.sleepQuietly(crawlerWaitMillis);
        }
    }

    public void delayByRules() {
        final long delay = getDelay();
        if (delay > 0) {
            ThreadUtil.sleep(delay);
        }
    }

    protected long getDelay() {
        if (ruleList.isEmpty()) {
            return 0;
        }
        final Calendar cal = getCurrentCal();

                }
                if (logger.isDebugEnabled()) {
                    logger.debug("Waiting threads: {}", waitingThreadNames);
                }
                ThreadUtil.sleep(systemCpuCheckInterval);
                current = getSystemCpuPercent();
            }
        } finally {
            waitingThreadNames.remove(threadName);
        }
    }

                        .anyMatch(a -> a.getName().equals(target.getName()) && a.getVersion().equals(target.getVersion()));
                if (!exists) {
                    ThreadUtil.sleep(500);
                    continue;
                }
                assertTrue(exists);
                done = true;
                break;
            }
            assertTrue(done);
        }

                dataCrawlingThreadStatusList.set(startedCrawlerNum, Constants.RUNNING);
                startedCrawlerNum++;
                activeCrawlerNum++;
                ThreadUtil.sleep(crawlingExecutionInterval);
                continue;
            }

            // check status
            for (int i = 0; i < startedCrawlerNum; i++) {

                    } else {
                        final long interval = fessConfig.getThumbnailGeneratorIntervalAsInteger().longValue();
                        if (interval > 0) {
                            ThreadUtil.sleep(interval);
                        }
                    }
                } else {
                    logger.warn("{} is not available.", generatorName);
                }

                return;
            }
            ThreadUtil.sleep(1000L);
        }
        fail("could not start job.");
    }

    protected static void waitJob(final String namePrefix) {
        Boolean isRunning = false;
        int count = 0;

        while (count < 300 && !isRunning) { // Wait until the crawler starts
            ThreadUtil.sleep(500);
            count++;

                    final long interval = updateInterval - updateTime;
                    if (interval > 0) {
                        // sleep
                        ThreadUtil.sleep(interval); // 10 sec (default)
                    }

                    systemHelper.calibrateCpuLoad();
                    systemHelper.waitForNoWaitingThreads();

            reader.addSort(SortBuilders.scoreSort());
            return reader;
        }, docPerReq, () -> {
            systemHelper.calibrateCpuLoad();
            ThreadUtil.sleep(interval);
        }).then(response -> {
            refresh();
            success.accept(true);
        }).error(t -> error.accept(t));
    }

    public void purgeDocumentSuggest(final LocalDateTime time) {