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Java > Open Source Codes > de > nava > informa > utils > poller > PersistenceObserver


1 //
2 // Informa -- RSS Library for Java
3 // Copyright (c) 2002 by Niko Schmuck
4 //
5 // Niko Schmuck
6 // http://sourceforge.net/projects/informa
7 // mailto:niko_schmuck@users.sourceforge.net
8 //
9 // This library is free software.
10 //
11 // You may redistribute it and/or modify it under the terms of the GNU
12 // Lesser General Public License as published by the Free Software Foundation.
13 //
14 // Version 2.1 of the license should be included with this distribution in
15 // the file LICENSE. If the license is not included with this distribution,
16 // you may find a copy at the FSF web site at 'www.gnu.org' or 'www.fsf.org',
17 // or you may write to the Free Software Foundation, 675 Mass Ave, Cambridge,
18 // MA 02139 USA.
19 //
20 // This library is distributed in the hope that it will be useful,
21 // but WITHOUT ANY WARRANTY; without even the implied waranty of
22 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 // Lesser General Public License for more details.
24 //
25 // $Id: PersistenceObserver.java,v 1.4 2004/09/02 09:13:58 spyromus Exp $
26 //
27
28 package de.nava.informa.utils.poller;
29
30 import de.nava.informa.core.ChannelIF;
31 import de.nava.informa.core.ItemIF;
32 import de.nava.informa.utils.manager.PersistenceManagerIF;
33 import de.nava.informa.utils.manager.PersistenceManagerException;
34
35 /**
36  * Watches for event about new items and calls given manager to create items in channels.
37  *
38  * @author Aleksey Gureev (spyromus@noizeramp.com)
39  */
40 public class PersistenceObserver implements PollerObserverIF {
41   private PersistenceManagerIF manager;
42
43   /**
44    * Creates observer.
45    *
46    * @param manager persistence manager to use.
47    *
48    * @throws IllegalArgumentException if manager isn't specified.
49    */
50   public PersistenceObserver(PersistenceManagerIF manager) {
51     if (manager == null) {
52       throw new IllegalArgumentException JavaDoc("Manager should be specified.");
53     }
54
55     this.manager = manager;
56   }
57
58   /**
59    * Invoked by Poller when new item is approved for addition. Item is transient
60    * and should be added to specified channel.
61    *
62    * @param item item added.
63    * @param channel destination channel.
64    */
65   public final void itemFound(ItemIF item, ChannelIF channel) {
66     try {
67       manager.createItem(channel, item);
68     } catch (PersistenceManagerException e) {
69       // We can do nothing here.
70 }
71   }
72
73   /**
74    * Invoked by Poller when poller of the channel failed.
75    *
76    * @param channel channel.
77    * @param e original cause of failure.
78    */
79   public void channelErrored(ChannelIF channel, Exception JavaDoc e) {
80   }
81
82   /**
83    * Invoked when Poller detected changes in channel information (title and etc).
84    *
85    * @param channel channel.
86    */
87   public void channelChanged(ChannelIF channel) {
88     try {
89       manager.updateChannel(channel);
90     } catch (PersistenceManagerException e) {
91       // We can do nothing here.
92 }
93   }
94
95   /**
96    * Invoked by Poller when checking of the channel started.
97    *
98    * @param channel channel.
99    */
100   public void pollStarted(ChannelIF channel) {
101   }
102
103   /**
104    * Invoked by Poller when checking of the channel finished.
105    *
106    * @param channel channel.
107    */
108   public void pollFinished(ChannelIF channel) {
109   }
110 }
111
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