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Java > Open Source Codes > com > sun > syndication > fetcher > samples > FeedReader


1 /*
2  * Copyright 2004 Sun Microsystems, Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *
16  */
17
18 package com.sun.syndication.fetcher.samples;
19 import java.net.URL JavaDoc;
20
21 import com.sun.syndication.feed.synd.SyndFeed;
22 import com.sun.syndication.fetcher.FeedFetcher;
23 import com.sun.syndication.fetcher.FetcherEvent;
24 import com.sun.syndication.fetcher.FetcherListener;
25 import com.sun.syndication.fetcher.impl.FeedFetcherCache;
26 import com.sun.syndication.fetcher.impl.HashMapFeedInfoCache;
27 import com.sun.syndication.fetcher.impl.HttpURLFeedFetcher;
28 /**
29  * Reads and prints any RSS/Atom feed type. Converted from the
30  * original Rome sample FeedReader
31  * <p>
32  * @author Alejandro Abdelnur
33  * @author Nick Lothian
34  *
35  */
36 public class FeedReader {
37     public static void main(String JavaDoc[] args) {
38         boolean ok = false;
39         if (args.length==1) {
40             try {
41                 URL JavaDoc feedUrl = new URL JavaDoc(args[0]);
42                 FeedFetcherCache feedInfoCache = HashMapFeedInfoCache.getInstance();
43                 FeedFetcher fetcher = new HttpURLFeedFetcher(feedInfoCache);
44
45                 FetcherEventListenerImpl listener = new FetcherEventListenerImpl();
46
47                 fetcher.addFetcherEventListener(listener);
48
49                 System.err.println("Retrieving feed " + feedUrl);
50                 // Retrieve the feed.
51 // We will get a Feed Polled Event and then a
52 // Feed Retrieved event (assuming the feed is valid)
53 SyndFeed feed = fetcher.retrieveFeed(feedUrl);
54
55                 System.err.println(feedUrl + " retrieved");
56                 System.err.println(feedUrl + " has a title: " + feed.getTitle() + " and contains " + feed.getEntries().size() + " entries.");
57                 // We will now retrieve the feed again. If the feed is unmodified
58 // and the server supports conditional gets, we will get a "Feed
59 // Unchanged" event after the Feed Polled event
60 System.err.println("Polling " + feedUrl + " again to test conditional get support.");
61                 SyndFeed feed2 = fetcher.retrieveFeed(feedUrl);
62                 System.err.println("If a \"Feed Unchanged\" event fired then the server supports conditional gets.");
63
64                 ok = true;
65             }
66             catch (Exception JavaDoc ex) {
67                 System.out.println("ERROR: "+ex.getMessage());
68                 ex.printStackTrace();
69             }
70         }
71
72         if (!ok) {
73             System.out.println();
74             System.out.println("FeedReader reads and prints any RSS/Atom feed type.");
75             System.out.println("The first parameter must be the URL of the feed to read.");
76             System.out.println();
77         }
78
79     }
80
81     static class FetcherEventListenerImpl implements FetcherListener {
82         /**
83          * @see com.sun.syndication.fetcher.FetcherListener#fetcherEvent(com.sun.syndication.fetcher.FetcherEvent)
84          */
85         public void fetcherEvent(FetcherEvent event) {
86             String JavaDoc eventType = event.getEventType();
87             if (FetcherEvent.EVENT_TYPE_FEED_POLLED.equals(eventType)) {
88                 System.err.println("\tEVENT: Feed Polled. URL = " + event.getUrlString());
89             } else if (FetcherEvent.EVENT_TYPE_FEED_RETRIEVED.equals(eventType)) {
90                 System.err.println("\tEVENT: Feed Retrieved. URL = " + event.getUrlString());
91             } else if (FetcherEvent.EVENT_TYPE_FEED_UNCHANGED.equals(eventType)) {
92                 System.err.println("\tEVENT: Feed Unchanged. URL = " + event.getUrlString());
93             }
94         }
95     }
96 }
97
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