Added cache that keeps hashtags for scope with a TTL of 5 minutes

git-svn-id: http://svn.research-infrastructures.eu/public/d4science/gcube/trunk/portlets/user/top-topics@128785 82a268e6-3cf1-43bd-a215-b396298e98cf

src/main/java/org/gcube/portlets/user/topics/server/TopicServiceImpl.java

@@ -21,6 +21,7 @@ import org.gcube.portal.databook.server.DBCassandraAstyanaxImpl;
 import org.gcube.portal.databook.server.DatabookStore;
 import org.gcube.portal.databook.shared.Feed;
 import org.gcube.portlets.user.topics.client.TopicService;
+import org.gcube.portlets.user.topics.server.cache.TopicsCacheImpl;
 import org.gcube.portlets.user.topics.shared.HashTagAndOccurrence;
 import org.gcube.portlets.user.topics.shared.HashtagsWrapper;
 import org.gcube.vomanagement.usermanagement.GroupManager;
@@ -87,11 +88,32 @@ public class TopicServiceImpl extends RemoteServiceServlet implements TopicServi
 	 */
 	@Override
 	public HashtagsWrapper getHashtags() {
-		ArrayList<String> hashtagsChart = new ArrayList<>();
+		ArrayList<String> hashtagsChart;
 		ASLSession session = getASLSession();
 
+		String userName = session.getUsername();
+		boolean isInfrastructure = isInfrastructureScope();
+		String currentScope = session.getScope();
+
 		long timestampStart = System.currentTimeMillis();
 
+		// get cache reference
+		TopicsCacheImpl topicsCache = TopicsCacheImpl.getCacheInstance();
+
+		hashtagsChart = topicsCache.get(currentScope);
+
+		if(hashtagsChart != null){
+			
+			_log.debug("TopTopics for scope " + currentScope + " retrieved from the cache");
+			
+		}
+		else{
+			
+			_log.debug("TopTopics for scope " + currentScope + " are not in the cache, evaluating them...");
+			
+			// create array
+			hashtagsChart = new ArrayList<String>();
+			
 			// get the reference time 
 			Calendar referenceTime = Calendar.getInstance();
 			int currentMonth = referenceTime.get(Calendar.MONTH); // jan = 0, ..... dec = 11
@@ -101,9 +123,6 @@ public class TopicServiceImpl extends RemoteServiceServlet implements TopicServi
 			SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
 			_log.debug("Reference time for trending topics is " + format.format(referenceTime.getTime()));
 
-		String userName = session.getUsername();
-		boolean isInfrastructure = isInfrastructureScope();
-		
 			try {
 				//in case the portal is restarted and you have the social home open it will get test.user (no callback to set session info)
 				//this check just return nothing if that happens
@@ -201,15 +220,18 @@ public class TopicServiceImpl extends RemoteServiceServlet implements TopicServi
 					String hashtagLink = "<a class=\"topiclink\" href=" + href + ">"+hashtag+"</a>";
 					hashtagsChart.add(hashtagLink);
 				}
+				
+				// update the cache
+				topicsCache.insert(currentScope, hashtagsChart);
 			}
 			catch (Exception e) {
 				e.printStackTrace();
 				return null;
 			}
-		
+		}
 
 		long timestampEnd = System.currentTimeMillis() - timestampStart;
-		_log.debug("Overall time to retrieve hastags is " + timestampEnd);
+		_log.debug("Overall time to retrieve hastags is " + timestampEnd + "ms");
 
 		return new HashtagsWrapper(isInfrastructure, hashtagsChart);
 	}

src/main/java/org/gcube/portlets/user/topics/server/cache/CacheInterface.java

@@ -0,0 +1,26 @@
+package org.gcube.portlets.user.topics.server.cache;
+
+/**
+ * Cache interface
+ * @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
+ * @param <K> the key type
+ * @param <V> the value type
+ */
+public interface CacheInterface <K,V>{
+
+	/**
+	 * Retrieve a value V from the cache
+	 * @param key
+	 * @return
+	 */
+	public V get(K key);
+	
+	/**
+	 * Insert an object V with key K into the cache
+	 * @param key
+	 * @param value
+	 * @return
+	 */
+	public boolean insert(K key, V value);
+	
+}

src/main/java/org/gcube/portlets/user/topics/server/cache/CacheUtilities.java

@@ -0,0 +1,26 @@
+package org.gcube.portlets.user.topics.server.cache;
+
+/**
+ * Utility functions for caches
+ * @author Costantino Perciante at ISTI-CNR 
+ * (costantino.perciante@isti.cnr.it)
+ *
+ */
+public class CacheUtilities {
+	/**
+	 * Check if the bean expired
+	 * @param beanTimestamp
+	 * @param ttl
+	 * @return <true> if expired, <false> otherwise
+	 */
+	public static boolean expired(long beanTimestamp, long ttl){
+		
+		long currentTime = System.currentTimeMillis();
+		
+		if((beanTimestamp + ttl) <= currentTime)
+			return true;
+		else
+			return false;
+		
+	}
+}

src/main/java/org/gcube/portlets/user/topics/server/cache/CacheValueBean.java

@@ -0,0 +1,40 @@
+package org.gcube.portlets.user.topics.server.cache;
+
+/**
+ * A bean object to be used as value within caches. It contains a TTL value too.
+ * @author Costantino Perciante at ISTI-CNR 
+ * (costantino.perciante@isti.cnr.it)
+ *
+ * @param <V> the value type
+ */
+public class CacheValueBean <V>{
+
+	private V value;
+	private long TTL;
+	
+	/**
+	 * @param value
+	 * @param tTL
+	 */
+	public CacheValueBean(V value, long ttl) {
+		super();
+		this.value = value;
+		this.TTL = ttl;
+	}
+	public V getValue() {
+		return value;
+	}
+	public void setValue(V value) {
+		this.value = value;
+	}
+	public long getTTL() {
+		return TTL;
+	}
+	public void setTTL(long ttl) {
+		this.TTL = ttl;
+	}
+	@Override
+	public String toString() {
+		return "CacheValueBean [value=" + value + ", TTL=" + TTL + "]";
+	}
+}

src/main/java/org/gcube/portlets/user/topics/server/cache/TopicsCacheImpl.java

@@ -0,0 +1,77 @@
+package org.gcube.portlets.user.topics.server.cache;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.slf4j.LoggerFactory;
+/**
+ * TopTopics cache: the key of each value is the scope
+ * @author Costantino Perciante at ISTI-CNR 
+ * (costantino.perciante@isti.cnr.it)
+ */
+public class TopicsCacheImpl implements CacheInterface<String, ArrayList<String>> {
+	
+	private static final org.slf4j.Logger logger = LoggerFactory.getLogger(TopicsCacheImpl.class);
+	
+	private static TopicsCacheImpl instance = new TopicsCacheImpl();
+	
+	/**
+	 * The hashmap
+	 */
+	private Map<String, CacheValueBean<ArrayList<String>>> cacheMap;
+	
+	/**
+	 * Cache entry expires after EXPIRED_AFTER ms
+	 */
+	private static final long EXPIRED_AFTER = 1000 * 60 * 2;
+	
+	/**
+	 * private constructor
+	 */
+	private TopicsCacheImpl(){
+		
+		this.cacheMap = new HashMap<String, CacheValueBean<ArrayList<String>>>();
+		
+	}
+	
+	/**
+	 * Retrieve the current cache instance object
+	 * @return
+	 */
+	public static TopicsCacheImpl getCacheInstance(){
+
+		return instance;
+
+	}
+
+	@Override
+	public ArrayList<String> get(String key) {
+		if(cacheMap.containsKey(key)){
+
+			 CacheValueBean<ArrayList<String>> bean = cacheMap.get(key);
+
+			if(CacheUtilities.expired(bean.getTTL(), EXPIRED_AFTER)){
+				cacheMap.remove(key);
+				logger.debug("TopTopics for scope " + key + "expired, return null");
+			}
+			else 
+				return bean.getValue();
+		}
+
+		return null;
+	}
+
+	@Override
+	public boolean insert(String key, ArrayList<String> value) {
+		CacheValueBean<ArrayList<String>> newBean = new CacheValueBean<ArrayList<String>>(value, System.currentTimeMillis());
+		
+		if(cacheMap.containsKey(key))
+			cacheMap.remove(key);
+		
+		cacheMap.put(key, newBean);
+		
+		return true;
+	}
+
+}