| Interface Summary | 
| SubCrawler | A SubCrawler accesses an InputStream and produces a stream of other DataObjects representing the resources
 found "inside". | 
| SubCrawlerFactory | SubCrawlerFactories create SubCrawlers capable of crawling FileDataObjects of specific mime types. | 
| SubCrawlerHandler | SubCrawlerHandlers are notified by a SubCrawler about additions and modifications of resources in an
 InputStream. | 
| SubCrawlerRegistry | A  SubCrawlerRegistry serves as a central registry for registering and obtaining SubCrawlerFactories. |