* the manager that can be used to remove a crawler from the queue.
* @return the action that needs to be performed by the Crawler.
*/
public CandidateCrawlAction pollCandidateCrawlAction(Crawler requestingCrawler,
CrawlQueueManager manager) {
CandidateCrawlAction action = registerdCandidateActions.remove(requestingCrawler);
if (action != null) {
workInProgressCandidateActions.put(requestingCrawler, action);
return action;
}
action = workInProgressCandidateActions.get(requestingCrawler);