package us.codecraft.webmagic.downloader;
import us.codecraft.webmagic.Page;
import us.codecraft.webmagic.Request;
import us.codecraft.webmagic.Task;
/**
* Downloader is the part that downloads web pages and store in Page object. <br>
* Downloader has {@link #setThread(int)} method because downloader is always the bottleneck of a crawler,
* there are always some mechanisms such as pooling in downloader, and pool size is related to thread numbers.
*
* @author code4crafter@gmail.com <br>
* @since 0.1.0
*/
public interface Downloader {
/**
* Downloads web pages and store in Page object.
*
* @param request request
* @param task task
* @return page
*/
public Page download(Request request, Task task);
/**
* Tell the downloader how many threads the spider used.
* @param threadNum number of threads
*/
public void setThread(int threadNum);
}