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simple GeoRSS parser

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simple GeoRSS parser

Postby flowdi » Mon Feb 04, 2008 9:32 pm

GeoRSS - geotagged flickr-image parser

example usage:
Syntax: [ Download ] [ Hide ]
Using java Syntax Highlighting
  1. List<ContentValue> points = RSS.parseFeed("http://api.flickr.com/services/feeds/geo/?tags=ufo&lang=en-us&format=rss_200");
Parsed in 0.030 seconds, using GeSHi 1.0.8.4

(geotagged photos from flickr)

to zoom, pan and display in a map see: :src: viewtopic.php?t=464

Syntax: [ Download ] [ Hide ]
Using java Syntax Highlighting
  1. public class RSS extends DefaultHandler {
  2.  
  3.         public static List parseFeed(String url) {
  4.                 SAXParserFactory spf = SAXParserFactory.newInstance();
  5.                 SAXParser sp;
  6.                 RSS handler = new RSS();
  7.                 try {
  8.                         sp = spf.newSAXParser();
  9.                         XMLReader xr = sp.getXMLReader();
  10.                         xr.setContentHandler(handler);
  11.                         xr.setErrorHandler(handler);
  12.                        
  13.                         URLConnection c = (new URL(url)).openConnection();
  14.                         c.setRequestProperty("User-Agent", "Android/m3-rc37a");
  15.                         xr.parse(new InputSource(c.getInputStream()));
  16.                        
  17.                 } catch (SAXParseException e) {
  18.                         e.printStackTrace();
  19.                 } catch (ParserConfigurationException e) {
  20.                         e.printStackTrace();
  21.                 } catch (SAXException e) {
  22.                         e.printStackTrace();
  23.                 } catch (MalformedURLException e) {
  24.                         e.printStackTrace();
  25.                 } catch (IOException e) {
  26.                         e.printStackTrace();
  27.                 }
  28.                
  29.                 return handler.result;
  30.         }
  31.  
  32.         private List result;
  33.         private ContentValues postBuffer;
  34.  
  35.         /* Efficiency is the name of the game here... */
  36.         private int mState;
  37.  
  38.         private static final int STATE_IN_ITEM = (1 << 2);
  39.         private static final int STATE_IN_ITEM_TITLE = (1 << 3);
  40.         private static final int STATE_IN_ITEM_LINK = (1 << 4);
  41.         private static final int STATE_IN_ITEM_DESC = (1 << 5);
  42.         private static final int STATE_IN_ITEM_DATE = (1 << 6);
  43.         private static final int STATE_IN_ITEM_AUTHOR = (1 << 7);
  44.         private static final int STATE_IN_TITLE = (1 << <img src="http://www.anddev.org/images/smilies/cool.png" alt="8)" title="Cool" />;
  45.         private static final int STATE_IN_ITEM_POINT = (1 << 9);
  46.  
  47.         private static HashMap<String, Integer> mStateMap;
  48.  
  49.         static
  50.         {
  51.                 mStateMap = new HashMap<String, Integer>();
  52.                 mStateMap.put("item", new Integer(STATE_IN_ITEM));
  53.                 mStateMap.put("entry", new Integer(STATE_IN_ITEM));
  54.                 mStateMap.put("title", new Integer(STATE_IN_ITEM_TITLE));
  55.                 mStateMap.put("link", new Integer(STATE_IN_ITEM_LINK));
  56.                 mStateMap.put("description", new Integer(STATE_IN_ITEM_DESC));
  57.                 mStateMap.put("content", new Integer(STATE_IN_ITEM_DESC));
  58.                 mStateMap.put("content:encoded", new Integer(STATE_IN_ITEM_DESC));
  59.                 mStateMap.put("dc:date", new Integer(STATE_IN_ITEM_DATE));
  60.                 mStateMap.put("updated", new Integer(STATE_IN_ITEM_DATE));
  61.                 mStateMap.put("pubDate", new Integer(STATE_IN_ITEM_DATE));
  62.                 mStateMap.put("dc:author", new Integer(STATE_IN_ITEM_AUTHOR));
  63.                 mStateMap.put("author", new Integer(STATE_IN_ITEM_AUTHOR));
  64.                 mStateMap.put("georss:point", new Integer(STATE_IN_ITEM_POINT));
  65.        
  66.         }
  67.  
  68.        
  69.         public RSS() {
  70.                 result = new ArrayList<Map>();
  71.         }
  72.        
  73.         public void startElement(String uri, String name, String qName,
  74.                         Attributes attrs)
  75.         {
  76.  
  77.                 Integer state = mStateMap.get(qName);
  78.  
  79.                 if (state != null)
  80.                 {
  81.                         mState |= state.intValue();
  82.  
  83.                         if (mState == STATE_IN_ITEM)
  84.                                 postBuffer = new ContentValues();
  85.                         else if ((mState & STATE_IN_ITEM) != 0 && state.intValue() == STATE_IN_ITEM_LINK)
  86.                         {
  87.                                 String href = attrs.getValue("href");
  88.  
  89.                                 if (href != null)
  90.                                         postBuffer.put("link", href);
  91.                         }
  92.                 }
  93.         }
  94.  
  95.         public void endElement(String uri, String name, String qName)
  96.         {
  97.                 Integer state = mStateMap.get(qName);
  98.  
  99.                 if (state != null)
  100.                 {
  101.                         mState &= ~(state.intValue());
  102.  
  103.                         if (state.intValue() == STATE_IN_ITEM)
  104.                         {
  105.                                 result.add(postBuffer);
  106.                         }
  107.                 }
  108.         }
  109.  
  110.         public void characters(char ch[], int start, int length)
  111.         {
  112.  
  113.                 if ((mState & STATE_IN_ITEM) == 0)
  114.                         return;
  115.  
  116.                 /*
  117.                  * We sort of pretended that mState was inclusive, but really only
  118.                  * STATE_IN_ITEM is inclusive here.  This is a goofy design, but it is
  119.                  * done to make this code a bit simpler and more efficient.
  120.                  */
  121.                 switch (mState)
  122.                 {
  123.                 case STATE_IN_ITEM | STATE_IN_ITEM_TITLE:
  124.                         postBuffer.put("title", new String(ch, start, length));
  125.                         break;
  126.                 case STATE_IN_ITEM | STATE_IN_ITEM_DESC:
  127.                         postBuffer.put("description", new String(ch, start, length));
  128.                         break;
  129.                 case STATE_IN_ITEM | STATE_IN_ITEM_LINK:
  130.                         postBuffer.put("link", new String(ch, start, length));
  131.                         break;
  132.                 case STATE_IN_ITEM | STATE_IN_ITEM_DATE:
  133.                         postBuffer.put("date", new String(ch, start, length));
  134.                         break;
  135.                 case STATE_IN_ITEM | STATE_IN_ITEM_AUTHOR:
  136.                         postBuffer.put("author", new String(ch, start, length));
  137.                         break;
  138.                 case STATE_IN_ITEM | STATE_IN_ITEM_POINT:
  139.                         String[] latlng = (new String(ch, start, length)).split(" ");
  140.                         postBuffer.put("lat", (int)(Double.valueOf(latlng[0])*1000000));
  141.                         postBuffer.put("lng", (int)(Double.valueOf(latlng[1])*1000000));
  142.                         break;
  143.                 default:
  144.                         /* Don't care... */
  145.                 }
  146.         }
  147. }
Parsed in 0.050 seconds, using GeSHi 1.0.8.4
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flowdi
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Postby plusminus » Mon Feb 04, 2008 10:20 pm

Aw man this is really goofy (or better to say optimized ^^).
But anyway, thanks for sharing your code :).

Took some seconds to realize, what the hell you were doing there with the shifting and binary OR's :lol:
Idea is really cool but could be easier to understand ;)

Best Regards,
plusminus
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Postby flowdi » Tue Feb 05, 2008 5:08 pm

Hey you are really a caring admin plusminus :)
I like anddev and just wanted to contribute something back.
Your approval isn't due to me
just took the code from
http://code.google.com/p/android-rss/
and extended the georss:point
(don't understand the binary-shifting myself ;))
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Postby plusminus » Tue Feb 05, 2008 11:15 pm

Hello flowdi,
flowdi wrote:Hey you are really a caring admin plusminus :)

Doing the best I can :)
flowdi wrote:I like anddev and just wanted to contribute something back.

Taking and giving is the perfect base for good community :)
Or would you prefer others to keep their in secret ;)
flowdi wrote:Your approval isn't due to me
just took the code from
http://code.google.com/p/android-rss/
and extended the georss:point
(don't understand the binary-shifting myself ;))

Having a second look its even relatively easy to understand, and "smart" what he does.
With some comments it would be easy understand on the first look.

All status codes are a row of zeros with a single 1 in it, like 00010000 the position of the 1 depends on how far it got shifted (here it should be: "(1 << 4)"):
In startelement:
Syntax: [ Download ] [ Hide ]
Using java Syntax Highlighting
  1.           // convert tag-name to bit flag( like: "description" --> STATE_IN_ITEM_DESC)
  2.           Integer state = mStateMap.get(qName);
  3.  
  4.           if (state != null)
  5.           {
  6.                // Binary OR means i.e. :
  7.                // Before mState == 00000001
  8.                // mState |= 00010000  --> 00010001              
  9.                mState |= state.intValue();
Parsed in 0.034 seconds, using GeSHi 1.0.8.4

So every 1 (or Bit) is a marker, where/how_deep we are in the xml-tree, which gets compared to in the switch of the characters()-method:
Syntax: [ Download ] [ Hide ]
Using java Syntax Highlighting
  1.           switch (mState)
  2.           {
  3.           case STATE_IN_ITEM | STATE_IN_ITEM_TITLE:
Parsed in 0.034 seconds, using GeSHi 1.0.8.4


But in my view readability goes before such tiny performance-tweaks ;)

Regards,
plusminus
Last edited by plusminus on Wed Feb 06, 2008 5:06 pm, edited 1 time in total.
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Postby flowdi » Wed Feb 06, 2008 10:39 am

Thanks for the explanation :)
that's really tricky!
(and actually not that unreadable - at least I could modify/extend it without knowing exactly what was going on;))
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Postby plusminus » Wed Feb 06, 2008 5:06 pm

Yes, with comments it would have been 100x easier to understand ^^

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plusminus
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Postby bluefloyd8 » Sun Feb 10, 2008 10:57 am

Geez! I wrote my own parser (using SAX) for GeoRss and made my own list view. Why couldnt I have seen this earlier and saved myself some work!!

This is actually one of the things I sort of expected Android to come with by default. Seems to me that GeoRss is going to become very popular in Android applications.
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Postby plusminus » Sun Feb 10, 2008 12:56 pm

You should probably check anddev even more often :D

Regards,
plusminus
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