Feed interface provides 'sortEntries' method, it takes a comparator and sort the entries by using comparator.
Example
feed.sortEntries(new Comparator(){
@Override
public int compare(Entry e1, Entry e2) {
return e1.getTitle().compareTo(e2.getTitle());
}
});
Above snippet sort the entries by using the title of the entry.
Following is the complete working application.
FeedUtil.java
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Optional;
import java.util.zip.GZIPInputStream;
import org.apache.abdera.Abdera;
import org.apache.abdera.model.Document;
import org.apache.abdera.model.Feed;
import org.apache.abdera.parser.Parser;
/**
* Utility class to parse Atom feed.
*
* Usage :
*
*Instantiate FeedUtil with atom document url. Call the getFeed method
*to get the feed document associated with url.
*
*
* @author Hari Krishna Gurram
*
*/
public class FeedUtil {
private String url;
private InputStream in = null;
private Feed feed = null;
HttpURLConnection conn = null;
public FeedUtil(String url) {
this.url = url;
}
/**
*
* @param url
* @return Optional.empty if url is null (or) unable to parse the url, else
* return the Document object.
*/
private OptionalDocumentFeed>> getDocument() {
if (url == null) {
return Optional.empty();
}
try {
URL urlTemp = new URL(url);
conn = (HttpURLConnection) urlTemp.openConnection();
conn.setRequestProperty("Accept-Encoding", "gzip");
conn.connect();
String contentEncoding = conn.getContentEncoding();
boolean isGzip = contentEncoding != null && contentEncoding.contains("gzip");
in = !isGzip ? conn.getInputStream() : new GZIPInputStream(conn.getInputStream());
Abdera abdera = Abdera.getInstance();
Parser parser = abdera.getParser();
DocumentFeed> document = parser.parse(in, url.toString());
return Optional.of(document);
} catch (Exception e) {
e.printStackTrace();
}
return Optional.empty();
}
/**
*
* @return the Feed object associated with given {@link url}. In any case if
* the feed creation is failed, then it return Optional.empty().
*/
public synchronized OptionalFeed> getFeed() {
if (feed != null) {
return Optional.of(feed);
}
OptionalDocumentFeed>> documentOpt = getDocument();
if (!documentOpt.isPresent()) {
return Optional.empty();
}
DocumentFeed> document = documentOpt.get();
feed = document.getRoot();
return Optional.of(feed);
}
public void closeStreamAndConnection() {
if (in != null) {
try {
in.close();
//System.out.println("\nInput Stream is closed");
} catch (IOException e1) {
e1.printStackTrace();
}
}
if (conn != null) {
conn.disconnect();
//System.out.println("Connection is disconnected");
}
}
/**
* This is just a safety check, if user forget to close the stram, it will
* be closed once object is out of scope.
*/
@Override
public void finalize() {
closeStreamAndConnection();
}
}
ParserDemo.java
import java.io.IOException;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import java.util.Optional;
import org.apache.abdera.model.Entry;
import org.apache.abdera.model.Feed;
import org.apache.abdera.parser.ParseException;
public class ParserDemo {
private static String url = "http://self-learning-java-tutorial.blogspot.in/atom.xml";
public static void main(String args[]) throws ParseException, IOException {
FeedUtil util = new FeedUtil(url);
OptionalFeed> feedOpt = util.getFeed();
if (!feedOpt.isPresent()) {
System.out.println("No feed present");
return;
}
Feed feed = feedOpt.get();
feed.sortEntries(new ComparatorEntry>(){
@Override
public int compare(Entry e1, Entry e2) {
return e1.getTitle().compareTo(e2.getTitle());
}
});
ListEntry> entries = feed.getEntries();
for (Entry entry : entries) {
String title = entry.getTitle();
Date editedDate = entry.getUpdated();
System.out.println("title : " + title + " editedDate : " + editedDate);
}
util.closeStreamAndConnection();
}
}
Sample Output
title : Apache Commons CLI Tutorial editedDate : Fri Dec 16 22:00:00 IST 2016
title : C#: Socket Programming editedDate : Sat Dec 10 13:02:13 IST 2016
title : C#: Get the version of zeroMQ used in the application editedDate : Wed Dec 14 21:08:34 IST 2016
title : C#: zeroMQ: Publish-subscribe model sockets editedDate : Wed Dec 14 21:07:09 IST 2016
title : Client in C# and Server in Java editedDate : Sat Dec 10 14:41:59 IST 2016
title : Commons CLI : Options class editedDate : Fri Dec 16 21:03:47 IST 2016
title : Commons CLI: Add multiple arguments to an option editedDate : Fri Dec 16 21:10:33 IST 2016
title : Commons CLI: Boolean options editedDate : Fri Dec 16 21:07:02 IST 2016
title : Commons CLI: Option: Specify single command line option editedDate : Fri Dec 16 19:48:44 IST 2016
title : Commons CLI: OptionGroup: group mutually Exclusive options editedDate : Fri Dec 16 21:23:39 IST 2016
title : Commons CLI: Parsing command line options editedDate : Fri Dec 16 21:24:04 IST 2016
title : Commons CLI: Print command line argument in the order you inserted editedDate : Fri Dec 16 21:21:35 IST 2016
title : Commons-CLI Define options using builder editedDate : Fri Dec 16 20:59:50 IST 2016
title : Commons-CLI: Set the display name for the argument editedDate : Fri Dec 16 20:56:15 IST 2016
title : Commons-CLI: Setting the compulsory options editedDate : Fri Dec 16 21:13:59 IST 2016
title : SWT: Focus listeners editedDate : Mon Dec 12 19:54:58 IST 2016
title : SWT: Mouse listeners editedDate : Fri Dec 09 08:36:39 IST 2016
title : SWT: Scale widget editedDate : Sat Dec 17 08:38:55 IST 2016
title : SWT: Slider editedDate : Sat Dec 17 08:39:42 IST 2016
title : SWT: TabFolder widget editedDate : Thu Dec 15 10:47:20 IST 2016
title : SWT: Table widget editedDate : Tue Dec 13 17:49:43 IST 2016
title : SWT: Text listeners editedDate : Fri Dec 09 20:21:59 IST 2016
title : Two way communication in C# client and socket editedDate : Sat Dec 10 13:06:51 IST 2016
title : zeroMQ C# Tutorial editedDate : Wed Dec 14 21:12:01 IST 2016
title : zeroMQ: Hello World Application editedDate : Wed Dec 14 20:56:36 IST 2016
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