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Java > Open Source Codes > RSSReader


1 // modified by Aleksander Slominski
2 // based on http://www.xml.com/pub/a/2002/05/22/parsing.html?page=2
3
4 import java.io.*;
5 import java.net.*;
6 import java.util.*;
7
8 import org.xmlpull.v1.*;
9
10 public class RSSReader {
11
12     public static void main(String JavaDoc [] args)
13     {
14
15         // create an instance of RSSReader
16 RSSReader rssreader = new RSSReader();
17
18         try {
19             XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
20             XmlPullParser parser = factory.newPullParser();
21             String JavaDoc url = args[0];
22             InputStreamReader stream = new InputStreamReader(
23                 new URL(url).openStream());
24             parser.setInput(stream);
25             XmlSerializer writer = factory.newSerializer();
26             writer.setOutput(new OutputStreamWriter(System.out));
27             rssreader.convertRSSToHtml(parser, writer);
28         } catch (Exception JavaDoc e) {
29             e.printStackTrace(System.err);
30         }
31     }
32
33     public void convertRSSToHtml(XmlPullParser parser, XmlSerializer writer)
34         throws IOException, XmlPullParserException
35     {
36         // <!ELEMENT rss (channel)>
37 if (parser.nextTag() == XmlPullParser.START_TAG
38             && parser.getName().equals("rss"))
39         {
40             writer.startTag(null,"html");
41             if (parser.nextTag() == XmlPullParser.START_TAG
42                 && parser.getName().equals("channel"))
43             {
44                 convertChannelToHtml(parser, writer);
45                 parser.require(XmlPullParser.END_TAG, null, "channel");
46             } else {
47                 new RuntimeException JavaDoc("expectd channel start tag not "+parser.getPositionDescription());
48             }
49             parser.nextTag();
50             parser.require(XmlPullParser.END_TAG, null, "rss");
51             writer.endTag(null, "html");
52             writer.flush();
53         } else {
54             throw new RuntimeException JavaDoc("expectd an RSS document at" + parser.getPositionDescription());
55         }
56     }
57
58     public void convertChannelToHtml(XmlPullParser parser, XmlSerializer writer)
59         throws IOException, XmlPullParserException
60     {
61         // <!ELEMENT channel (title | description | link | language | item+ | rating? | image? | textinput? | copyright? | pubDate? | lastBuildDate? | docs? | managingEditor? | webMaster? | skipHours? | skipDays?)*>
62 boolean seenBody = false; //assumption that title is before items ...
63 while (parser.nextTag() != XmlPullParser.END_TAG) { // this guranteed by well formednes of XML && parser.getName().equals("channel"))) {
64 // if (parser.getEventType() == XmlPullParser.START_TAG) { //guranteed by nextTag
65 // <!ELEMENT title (#PCDATA)>
66 if(parser.getName().equals("title") && !seenBody) {
67                 writer.startTag(null,"head");
68                 writer.startTag(null,"title").text(parser.nextText()).endTag(null,"title");
69                 writer.endTag(null,"head");
70             } else if(parser.getName().equals("item")) {
71                 if(!seenBody) {
72                     writer.startTag(null, "body");
73                     seenBody = true;
74                 }
75                 convertItemToHtml(parser, writer);
76             } else {
77                 // skip any element content including sub elements...
78 int level = 1;
79                 while (level > 0) {
80                     switch(parser.next()) {
81                         case XmlPullParser.START_TAG: ++level; break;
82                         case XmlPullParser.END_TAG: --level; break;
83                     }
84                 }
85             }
86         }
87         if(seenBody) writer.endTag(null, "body");
88     }
89
90     public void convertItemToHtml(XmlPullParser parser, XmlSerializer writer)
91         throws IOException, XmlPullParserException
92     {
93         writer.startTag(null, "p");
94         //<!ELEMENT item (title | link | description)*>
95 String JavaDoc title = null, link = null, description = null;
96         while (parser.nextTag() != XmlPullParser.END_TAG) {
97             if (parser.getName().equals("title")) {
98                 title = parser.nextText();
99             } else if (parser.getName().equals("link")) {
100                 link = parser.nextText();
101             } else if (parser.getName().equals("description")) {
102                 description = parser.nextText();
103             }
104         }
105
106         //HashMap attributes = new HashMap(1);
107 //if(link != null) attributes.put("href", link);
108 //writer.beginElement("a",attributes);
109 writer.startTag(null, "a");
110         writer.attribute(null, "href", link);
111         if(title != null) {
112             writer.text(title);
113         } else {
114             writer.text(link);
115         }
116         writer.endTag(null,"a");
117
118         //writer.writeEmptyElement("br");
119 writer.startTag(null, "br").endTag(null, "br");
120
121         if(description != null) writer.text(description);
122
123         writer.endTag(null, "p"); // end the "p" element
124 }
125 }
126
127
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