Rome v0.1 Tutorial, Using Rome to read a syndication feed

Software requirements: J2SE 1.4+, Xerces 2.4.0, JDOM B10, Commons Codec 1.2 and Rome 0.1.

Rome represents syndication feeds (RSS and Atom) as instances of the com.rometools.rome.synd.SyndFeedI interface. The SyndFeedI interfaces and its properties follow the Java Bean patterns. The default implementations provided with Rome are all lightweight classes.

Rome includes parsers to process syndication feeds into SyndFeedI instances. The SyndInput class handles the parsers using the correct one based on the syndication feed being processed. The developer does not need to worry about selecting the right parser for a syndication feed, the SyndInput will take care of it by peeking at the syndication feed structure. All it takes to read a syndication feed using Rome are the following 2 lines of code:

SyndInput input = new SyndInput();
SyndFeedI feed = input.build(feedUrl.openStream());

The first line creates a SyndInput instance that will work with any syndication feed type (RSS and Atom versions). The second line instructs the SyndInput to read the syndication feed from the InputStream of a URL pointing to the feed. The SyndInput.build() method returns a SyndFeedI instance that can be easily processed.

The default SyndFeedI implementation has a detailed and clear toString() implementation. The following line just prints it to the application's output.

System.out.println(feed);

Following is the full code for a Java application that reads a syndication feed and prints the SyndFeedI bean to the application's output.

package com.rometools.rome.samples;

import java.net.URL;
import com.rometools.rome.feed.synd.SyndFeedI;
import com.rometools.rome.io.SyndInput;

public class FeedReader {

    public static void main(String[] args) {
        boolean ok = false;
        if (args.length==1) {
            try {
                URL feedUrl = new URL(args[0]);

                SyndInput input = new SyndInput();
                SyndFeedI feed = input.build(feedUrl.openStream());

                System.out.println(feed);

                ok = true;
            }
            catch (Exception ex) {
                System.out.println("ERROR: "+ex.getMessage());
            }
        }

        if (!ok) {
            System.out.println();
            System.out.println("FeedReader reads and prints any RSS/Atom feed type.");
            System.out.println("The first parameter must be the URL of the feed to read.");
            System.out.println();
        }
    }

}