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Using the Rome Fetcher module to retrieve feeds

The HttpURLFeedFetcher class does the actual HTTP request. It relies on the FeedInfoCacheI interface which stores information about each feed required for conditional gets. Currently there is a single implementation of FeedInfoCacheI supplied: HashMapFeedInfoCache.

The basic usage of FeedFetcher is as follows:

FeedFetcherCache feedInfoCache = HashMapFeedInfoCache.getInstance();
FeedFetcher feedFetcher = new HttpURLFeedFetcher(feedInfoCache);
SyndFeed feed = feedFetcher.retrieveFeed(new URL(""));

Any subsequent fetches of by any FeedFetcher using feedInfoCache will now only retrieve the feed if it has changed.

FeedFetcher can be used without a cache if required. Simply create it using the zero-parameter constructor:

FeedFetcher feedFetcher = new HttpURLFeedFetcher();

A more complete sample (including the use of listener on Fetcher events) is included in the Rome Fetcher project

Note that there has been considerable discussion on the rome-dev list about the best way to manage the creation of the feed fetcher. Currently the client code needs to be responsible for creating specific implementations of the FeedFetcherI interface.