added in memory cache and redis cache and marked them as application scoped

src/main/java/com/commafeed/backend/cache/CacheService.java

@@ -1,31 +1,21 @@
 package com.commafeed.backend.cache;
 
-import java.util.concurrent.TimeUnit;
+import java.util.List;
+
+import org.apache.commons.codec.digest.DigestUtils;
 
 import com.commafeed.backend.model.Feed;
 import com.commafeed.backend.model.FeedEntry;
-import com.google.common.cache.Cache;
-import com.google.common.cache.CacheBuilder;
 
-public class CacheService {
+public abstract class CacheService {
 
-	Cache<String, Marker> entryCache = CacheBuilder.newBuilder()
-			.maximumSize(1000000).expireAfterWrite(24, TimeUnit.HOURS).build();
+	public abstract List<String> getLastEntries(Feed feed);
 
-	private static enum Marker {
-		INSTANCE
-	}
+	public abstract void setLastEntries(Feed feed, List<String> entries);
 
-	public boolean hasFeedEntry(Feed feed, FeedEntry entry) {
-		return entryCache.getIfPresent(buildKey(feed, entry)) == Marker.INSTANCE;
-	}
-
-	public void putFeedEntry(Feed feed, FeedEntry entry) {
-		entryCache.put(buildKey(feed, entry), Marker.INSTANCE);
-	}
-
-	private String buildKey(Feed feed, FeedEntry entry) {
-		return String.format("%s:%s:%s", feed.getId(), entry.getGuid(),
+	public String buildKey(Feed feed, FeedEntry entry) {
+		return DigestUtils.sha1Hex(entry.getGuid() +
 				entry.getUrl());
 	}
+
 }

src/main/java/com/commafeed/backend/cache/InMemoryCacheService.java

@@ -0,0 +1,46 @@
+package com.commafeed.backend.cache;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import javax.annotation.PostConstruct;
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.inject.Alternative;
+import javax.inject.Inject;
+
+import com.commafeed.backend.model.Feed;
+import com.commafeed.backend.services.ApplicationSettingsService;
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+
+@Alternative
+@ApplicationScoped
+public class InMemoryCacheService extends CacheService {
+
+	@Inject
+	ApplicationSettingsService applicationSettingsService;
+
+	private Cache<Long, List<String>> entryCache;
+
+	@PostConstruct
+	private void init() {
+		int capacity = applicationSettingsService.get().isHeavyLoad() ? 1000000 : 100;
+		entryCache = CacheBuilder.newBuilder()
+				.maximumSize(capacity).expireAfterWrite(24, TimeUnit.HOURS).build();
+	}
+
+	@Override
+	public List<String> getLastEntries(Feed feed) {
+		List<String> list = entryCache.getIfPresent(feed.getId());
+		if (list == null) {
+			list = Collections.emptyList();
+		}
+		return list;
+	}
+
+	@Override
+	public void setLastEntries(Feed feed, List<String> entries) {
+		entryCache.put(feed.getId(), entries);
+	}
+}

src/main/java/com/commafeed/backend/cache/RedisCacheService.java

@@ -0,0 +1,62 @@
+package com.commafeed.backend.cache;
+
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.inject.Alternative;
+
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.JedisPool;
+import redis.clients.jedis.JedisPoolConfig;
+import redis.clients.jedis.Pipeline;
+
+import com.commafeed.backend.model.Feed;
+import com.google.api.client.util.Lists;
+
+@Alternative
+@ApplicationScoped
+public class RedisCacheService extends CacheService {
+
+	private JedisPool pool = new JedisPool(new JedisPoolConfig(), "localhost");
+
+	@Override
+	public List<String> getLastEntries(Feed feed) {
+		List<String> list = Lists.newArrayList();
+		Jedis jedis = pool.getResource();
+		try {
+			String key = buildKey(feed);
+			Set<String> members = jedis.smembers(key);
+			for (String member : members) {
+				list.add(member);
+			}
+		} finally {
+			pool.returnResource(jedis);
+		}
+		return list;
+	}
+
+	@Override
+	public void setLastEntries(Feed feed, List<String> entries) {
+		Jedis jedis = pool.getResource();
+		try {
+			String key = buildKey(feed);
+
+			Pipeline pipe = jedis.pipelined();
+			pipe.del(key);
+			for (String entry : entries) {
+				pipe.sadd(key, entry);
+			}
+			pipe.expire(key, (int) TimeUnit.HOURS.toSeconds(24));
+			pipe.sync();
+		} finally {
+			pool.returnResource(jedis);
+		}
+	}
+
+	private String buildKey(Feed feed) {
+		return "feed:" + feed.getId();
+	}
+
+}

src/main/java/com/commafeed/backend/feeds/FeedRefreshTaskGiver.java

@@ -10,6 +10,8 @@ import javax.inject.Inject;
 import javax.inject.Singleton;
 
 import org.apache.commons.lang3.time.DateUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import com.commafeed.backend.MetricsBean;
 import com.commafeed.backend.dao.FeedDAO;
@@ -21,6 +23,8 @@ import com.google.common.collect.Queues;
 @Singleton
 public class FeedRefreshTaskGiver {
 
+	protected static final Logger log = LoggerFactory.getLogger(FeedRefreshTaskGiver.class);
+
 	@Inject
 	FeedDAO feedDAO;
 

src/main/java/com/commafeed/backend/feeds/FeedRefreshUpdater.java

@@ -31,6 +31,7 @@ import com.commafeed.backend.model.FeedSubscription;
 import com.commafeed.backend.pubsubhubbub.SubscriptionHandler;
 import com.commafeed.backend.services.ApplicationSettingsService;
 import com.commafeed.backend.services.FeedUpdateService;
+import com.google.api.client.util.Lists;
 import com.google.common.util.concurrent.Striped;
 
 @Singleton
@@ -141,9 +142,21 @@ public class FeedRefreshUpdater {
 			if (entries.isEmpty() == false) {
 				List<FeedSubscription> subscriptions = feedSubscriptionDAO
 						.findByFeed(feed);
+				List<String> lastEntries = cache.getLastEntries(feed);
+				List<String> currentEntries = Lists.newArrayList();
 				for (FeedEntry entry : entries) {
-					ok &= updateEntry(feed, entry, subscriptions);
+					String cacheKey = cache.buildKey(feed, entry);
+					if (!lastEntries.contains(cacheKey)) {
+						log.debug("cache miss for {}", entry.getUrl());
+						ok &= updateEntry(feed, entry, subscriptions);
+						metricsBean.entryCacheMiss();
+					} else {
+						log.debug("cache hit for {}", entry.getUrl());
+						metricsBean.entryCacheHit();
+					}
+					currentEntries.add(cacheKey);
 				}
+				cache.setLastEntries(feed, currentEntries);
 			}
 
 			if (applicationSettingsService.get().isPubsubhubbub()) {
@@ -171,15 +184,7 @@ public class FeedRefreshUpdater {
 		try {
 			locked = lock.tryLock(1, TimeUnit.MINUTES);
 			if (locked) {
-				if (!cache.hasFeedEntry(feed, entry)) {
-					log.debug("cache miss for {}", entry.getUrl());
-					feedUpdateService.updateEntry(feed, entry, subscriptions);
-					cache.putFeedEntry(feed, entry);
-					metricsBean.entryCacheMiss();
-				} else {
-					log.debug("cache hit for {}", entry.getUrl());
-					metricsBean.entryCacheHit();
-				}
+				feedUpdateService.updateEntry(feed, entry, subscriptions);
 				success = true;
 			} else {
 				log.error("lock timeout for " + feed.getUrl() + " - " + key);