CrawlStatusListener


1   /* Copyright (C) 2003 Internet Archive.
2    *
3    * This file is part of the Heritrix web crawler (crawler.archive.org).
4    *
5    * Heritrix is free software; you can redistribute it and/or modify
6    * it under the terms of the GNU Lesser Public License as published by
7    * the Free Software Foundation; either version 2.1 of the License, or
8    * any later version.
9    *
10   * Heritrix is distributed in the hope that it will be useful,
11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   * GNU Lesser Public License for more details.
14   *
15   * You should have received a copy of the GNU Lesser Public License
16   * along with Heritrix; if not, write to the Free Software
17   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18   */
19  package org.archive.crawler.event;
20  
21  import java.io.File  ;
22  
23  import org.archive.crawler.framework.CrawlController;
24  
25  
26  /**
27   * Listen for CrawlStatus events.
28   * 
29   * Classes that implement this interface can register themselves with
30   * a CrawlController to receive notifications about the events that
31   * affect a crawl job's current status.
32   *
33   * @author Kristinn Sigurdsson
34   *
35   * @see org.archive.crawler.framework.CrawlController#addCrawlStatusListener(CrawlStatusListener)
36   */
37  
38  public interface CrawlStatusListener {
39      /**
40       * Called on crawl start.
41       * @param message Start message.
42       */
43      public void crawlStarted(String   message);
44      
45      /**
46       * Called when a CrawlController is ending a crawl (for any reason)
47       *
48       * @param sExitMessage Type of exit. Should be one of the STATUS constants
49       * in defined in CrawlJob.
50       *
51       * @see org.archive.crawler.admin.CrawlJob
52       */
53      public void crawlEnding(String   sExitMessage);
54  
55      /**
56       * Called when a CrawlController has ended a crawl and is about to exit.
57       *
58       * @param sExitMessage Type of exit. Should be one of the STATUS constants
59       * in defined in CrawlJob.
60       *
61       * @see org.archive.crawler.admin.CrawlJob
62       */
63      public void crawlEnded(String   sExitMessage);
64  
65      /**
66       * Called when a CrawlController is going to be paused.
67       *
68       * @param statusMessage Should be
69       * {@link org.archive.crawler.admin.CrawlJob#STATUS_WAITING_FOR_PAUSE
70       * STATUS_WAITING_FOR_PAUSE}. Passed for convenience
71       */
72      public void crawlPausing(String   statusMessage);
73  
74      /**
75       * Called when a CrawlController is actually paused (all threads are idle).
76       *
77       * @param statusMessage Should be
78       * {@link org.archive.crawler.admin.CrawlJob#STATUS_PAUSED}. Passed for
79       * convenience
80       */
81      public void crawlPaused(String   statusMessage);
82  
83      /**
84       * Called when a CrawlController is resuming a crawl that had been paused.
85       *
86       * @param statusMessage Should be
87       * {@link org.archive.crawler.admin.CrawlJob#STATUS_RUNNING}. Passed for
88       * convenience
89       */
90      public void crawlResuming(String   statusMessage);
91      
92      /**
93       * Called by {@link CrawlController} when checkpointing.
94       * @param checkpointDir Checkpoint dir.  Write checkpoint state here.
95       * @throws Exception A fatal exception.  Any exceptions
96       * that are let out of this checkpoint are assumed fatal
97       * and terminate further checkpoint processing.
98       */
99      public void crawlCheckpoint(File   checkpointDir) throws Exception  ;
100 }
101
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