svn commit: r557339 - in /roller/trunk/apps/planet: src/java/org/apache/roller/planet/business/fetcher/ src/java/org/apache/roller/planet/business/updater/ test/java/org/apache/roller/planet/business/

[ag...@apache.org]

Author: agilliland
Date: Wed Jul 18 10:48:32 2007
New Revision: 557339

URL: http://svn.apache.org/viewvc?view=rev&rev=557339
Log:
minor change to FeedFetcher to support conditional feed fetching based on lastModified time of the subscription.  this is meant to help performance a little bit so that we don't waste time processing subscriptions that haven't changed since they were last fetched.

Modified:
    roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/FeedFetcher.java
    roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/RomeFeedFetcher.java
    roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/updater/SingleThreadedFeedUpdater.java
    roller/trunk/apps/planet/test/java/org/apache/roller/planet/business/RomeFeedFetcherTest.java

Modified: roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/FeedFetcher.java
URL: http://svn.apache.org/viewvc/roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/FeedFetcher.java?view=diff&rev=557339&r1=557338&r2=557339
==============================================================================
--- roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/FeedFetcher.java (original)
+++ roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/FeedFetcher.java Wed Jul 18 10:48:32 2007
@@ -18,6 +18,7 @@
 
 package org.apache.roller.planet.business.fetcher;
 
+import java.util.Date;
 import org.apache.roller.planet.pojos.Subscription;
 
 
@@ -47,4 +48,25 @@
      */
     public Subscription fetchSubscription(String feedURL) throws FetcherException;
     
+    
+    /**
+     * Conditionally fetch a single subscription.
+     *
+     * This method takes in a feed url and its known last modified date and should
+     * return a transient Subscription for the feed only if the given feed has
+     * been updated since the lastModified date.  This method is meant provide
+     * a more efficient way to fetch subscriptions which are being updated so
+     * subscriptions are not continually fetched when unnecessary.
+     *
+     * It is important to understand that this method will *NOT* return a 
+     * persistent version of an existing Subscription if it happens to
+     * exist.  This method is only here to pull feeds from their source 
+     * so that they may be used in any way desired by the rest of the system.
+     *
+     * @param feedURL The feed url to use when fetching the subscription.
+     * @return Subscription The fetched subscription.
+     * @throws FetcherException If there is an error fetching the subscription.
+     */
+    public Subscription fetchSubscription(String feedURL, Date lastModified) throws FetcherException;
+
 }

Modified: roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/RomeFeedFetcher.java
URL: http://svn.apache.org/viewvc/roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/RomeFeedFetcher.java?view=diff&rev=557339&r1=557338&r2=557339
==============================================================================
--- roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/RomeFeedFetcher.java (original)
+++ roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/fetcher/RomeFeedFetcher.java Wed Jul 18 10:48:32 2007
@@ -63,6 +63,15 @@
      */
     public Subscription fetchSubscription(String feedURL) 
             throws FetcherException {
+        return fetchSubscription(feedURL, null);
+    }
+    
+    
+    /**
+     * @inheritDoc
+     */
+    public Subscription fetchSubscription(String feedURL, Date lastModified) 
+            throws FetcherException {
         
         if(feedURL == null) {
             throw new IllegalArgumentException("feed url cannot be null");
@@ -114,6 +123,11 @@
             } catch (MalformedURLException ex) {
                 // should never happen since we check this above
             }
+        }
+        
+        // check if feed is unchanged and bail now if so
+        if(lastModified != null && !newSub.getLastUpdated().after(lastModified)) {
+            return null;
         }
         
         if(log.isDebugEnabled()) {

Modified: roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/updater/SingleThreadedFeedUpdater.java
URL: http://svn.apache.org/viewvc/roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/updater/SingleThreadedFeedUpdater.java?view=diff&rev=557339&r1=557338&r2=557339
==============================================================================
--- roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/updater/SingleThreadedFeedUpdater.java (original)
+++ roller/trunk/apps/planet/src/java/org/apache/roller/planet/business/updater/SingleThreadedFeedUpdater.java Wed Jul 18 10:48:32 2007
@@ -66,9 +66,14 @@
         try {
             // fetch the latest version of the subscription
             FeedFetcher fetcher = PlanetFactory.getPlanet().getFeedFetcher();
-            updatedSub = fetcher.fetchSubscription(sub.getFeedURL());
+            updatedSub = fetcher.fetchSubscription(sub.getFeedURL(), sub.getLastUpdated());
         } catch (FetcherException ex) {
             throw new UpdaterException("Error fetching updated subscription", ex);
+        }
+        
+        // if sub was unchanged then we are done
+        if(updatedSub == null) {
+            return;
         }
         
         // if this subscription hasn't changed since last update then we're done

Modified: roller/trunk/apps/planet/test/java/org/apache/roller/planet/business/RomeFeedFetcherTest.java
URL: http://svn.apache.org/viewvc/roller/trunk/apps/planet/test/java/org/apache/roller/planet/business/RomeFeedFetcherTest.java?view=diff&rev=557339&r1=557338&r2=557339
==============================================================================
--- roller/trunk/apps/planet/test/java/org/apache/roller/planet/business/RomeFeedFetcherTest.java (original)
+++ roller/trunk/apps/planet/test/java/org/apache/roller/planet/business/RomeFeedFetcherTest.java Wed Jul 18 10:48:32 2007
@@ -61,4 +61,23 @@
         assertTrue(sub.getEntries().size() > 0);
     }
     
+    
+    public void testFetchFeedConditionally() throws Exception {
+        
+        FeedFetcher feedFetcher = PlanetFactory.getPlanet().getFeedFetcher();
+
+        // fetch feed
+        Subscription sub = feedFetcher.fetchSubscription(feed_url);
+        assertNotNull(sub);
+        assertEquals(feed_url, sub.getFeedURL());
+        assertEquals("http://rollerweblogger.org/roller/", sub.getSiteURL());
+        assertEquals("Blogging Roller", sub.getTitle());
+        assertNotNull(sub.getLastUpdated());
+        assertTrue(sub.getEntries().size() > 0);
+        
+        // now do a conditional fetch and we should get back null
+        Subscription updatedSub = feedFetcher.fetchSubscription(feed_url, sub.getLastUpdated());
+        assertNull(updatedSub);
+    }
+    
 }