package ecologylab.concurrent;

import java.io.IOException;

import ecologylab.io.DownloadProcessor;
import ecologylab.net.ParsedURL;

/**
 * Objects that implement this interface can be passed to a {@link DownloadProcessor DownloadProcessor}.
 *
 * @author andruid
 */
public interface Downloadable
{
  
  /**
   * Called to start download.
   */
  public void performDownload()
      throws IOException;

  /**
   * Called in case an IO error happens.
   * @param e TODO
   */
  public void handleIoError(Throwable e);

  /**
   * True if the Downloadable has been recycled, and thus should not be downloaded.
   * 
   * @return
   */
  public boolean isRecycled();
  
  public void recycle();
  
  public BasicSite getSite();
  public BasicSite getDownloadSite();
  public ParsedURL location();
  public ParsedURL getDownloadLocation();
  
  /**
   * Can be used to reduce image download waits, in conjunction with BasicSite;
   * otherwise ignored.
   * 
   * @return
   */
  public boolean isImage();
  
  /**
   * 
   * @return	What to tell the user about what is being downloaded.
   */
  public String message();

  /**
   * @return If this downloadable is cached somewhere (e.g. in memory or in cache servers), so 
   * that we don't need to hit the original website.
   */
  public boolean isCached();
  
  public DownloadableLogRecord getLogRecord();
  
  //public void setDownloadableLogRecord(DownloadableLogRecord dlr);
}