[VIVO-1071] Add simple short-lived cache to reduce the number of expensive queries in generating the co-authorship / investigator graphs.

src/edu/cornell/mannlib/vitro/webapp/visualization/coauthorship/CoAuthorshipQueryRunner.java

@@ -4,11 +4,13 @@ package edu.cornell.mannlib.vitro.webapp.visualization.coauthorship;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
@@ -401,12 +403,12 @@ public class CoAuthorshipQueryRunner implements QueryRunner<CollaborationData> {
 								+ " core:relatedBy ?authorshipNode . \n"
 			+ "?authorshipNode rdf:type core:Authorship ;" 
 								+ " core:relates ?document . \n"
-            + "?document rdf:type bibo:Document . \n" 
+            + "?document rdf:type bibo:Document ; \n"
-			+ "?document core:relatedBy ?coAuthorshipNode . \n" 
+			+ "core:relatedBy ?coAuthorshipNode . \n"
-			+ "?coAuthorshipNode rdf:type core:Authorship . \n" 
+			+ "?coAuthorshipNode rdf:type core:Authorship ; \n"
-			+ "?coAuthorshipNode core:relates ?coAuthorPerson . \n" 
+			+ "core:relates ?coAuthorPerson . \n"
-			+ "?coAuthorPerson rdf:type foaf:Person . \n"
+			+ "?coAuthorPerson rdf:type foaf:Person ; \n"
-			+ "?coAuthorPerson rdfs:label ?coAuthorPersonLabel . \n"
+			+ "rdfs:label ?coAuthorPersonLabel . \n"
 			+ "OPTIONAL {  ?document core:dateTimeValue ?dateTimeValue . \n" 
 			+ "				?dateTimeValue core:dateTime ?publicationDate } .\n"
 			+ "} \n"
@@ -421,6 +423,33 @@ public class CoAuthorshipQueryRunner implements QueryRunner<CollaborationData> {
 	public CollaborationData getQueryResult()
 		throws MalformedQueryParametersException {
 
+		CollaborationData data = getCachedData(this.egoURI);
+		if (data != null) {
+			return data;
+		}
+
+		return getQueryResultAndCache();
+	}
+
+	private CollaborationData getCachedData(String egoURI) {
+		CollaborationDataCacheEntry entry = collaborationDataCache.get(egoURI);
+		if (entry != null && !entry.hasExpired()) {
+			entry.accessTime = new Date().getTime();
+			expireCache();
+			return entry.data;
+		}
+
+		return null;
+	}
+
+	private synchronized CollaborationData getQueryResultAndCache()
+			throws MalformedQueryParametersException {
+
+		CollaborationData data = getCachedData(this.egoURI);
+		if (data != null) {
+			return data;
+		}
+
 		if (StringUtils.isNotBlank(this.egoURI)) {
 			/*
         	 * To test for the validity of the URI submitted.
@@ -439,7 +468,51 @@ public class CoAuthorshipQueryRunner implements QueryRunner<CollaborationData> {
 
 		ResultSet resultSet	= executeQuery(generateEgoCoAuthorshipSparqlQuery(this.egoURI),
 				this.dataset);
-		return createQueryResult(resultSet);
+
+		data = createQueryResult(resultSet);
+
+		CollaborationDataCacheEntry newEntry = new CollaborationDataCacheEntry();
+
+		newEntry.uri = this.egoURI;
+		newEntry.data = data;
+		newEntry.creationTime = newEntry.accessTime = new Date().getTime();
+
+		// Remove dead entries
+		expireCache();
+
+		// Cache the new entry
+		collaborationDataCache.put(this.egoURI, newEntry);
+
+		return data;
 	}
 
+	private synchronized void expireCache() {
+		for (String key : collaborationDataCache.keySet()) {
+			CollaborationDataCacheEntry entry = collaborationDataCache.get(key);
+			if (entry != null && entry.hasExpired()) {
+				collaborationDataCache.remove(key);
+			}
+		}
+	}
+
+	private static final Map<String, CollaborationDataCacheEntry> collaborationDataCache = new ConcurrentHashMap<String, CollaborationDataCacheEntry>();
+
+	private static class CollaborationDataCacheEntry {
+		String uri;
+		CollaborationData data;
+		long creationTime;
+		long accessTime;
+
+		boolean hasExpired() {
+			long now = new Date().getTime();
+
+			// If it's older than five minutes, and it hasn't *just* been accessed, it's expired
+			if (creationTime < (now - 300000L) && accessTime < (now - 3000L)) {
+				return true;
+			}
+
+			// Otherwise, if it is more than 30 seconds old, expire it
+			return accessTime < (now - 30000L);
+		}
+	}
 }

src/edu/cornell/mannlib/vitro/webapp/visualization/coprincipalinvestigator/CoPIGrantCountQueryRunner.java

@@ -4,11 +4,13 @@ package edu.cornell.mannlib.vitro.webapp.visualization.coprincipalinvestigator;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
@@ -385,6 +387,33 @@ public class CoPIGrantCountQueryRunner implements QueryRunner<CollaborationData>
 	public CollaborationData getQueryResult()
 		throws MalformedQueryParametersException {
 
+		CollaborationData data = getCachedData(this.egoURI);
+		if (data != null) {
+			return data;
+		}
+
+		return getQueryResultAndCache();
+	}
+
+	private CollaborationData getCachedData(String egoURI) {
+		CollaborationDataCacheEntry entry = collaborationDataCache.get(egoURI);
+		if (entry != null && !entry.hasExpired()) {
+			entry.accessTime = new Date().getTime();
+			expireCache();
+			return entry.data;
+		}
+
+		return null;
+	}
+
+	private synchronized CollaborationData getQueryResultAndCache()
+			throws MalformedQueryParametersException {
+
+		CollaborationData data = getCachedData(this.egoURI);
+		if (data != null) {
+			return data;
+		}
+
 		if (StringUtils.isNotBlank(this.egoURI)) {
 			/*
 			 * To test for the validity of the URI submitted.
@@ -402,14 +431,55 @@ public class CoPIGrantCountQueryRunner implements QueryRunner<CollaborationData>
 		}
 
 		before = System.currentTimeMillis();
-	
 		ResultSet resultSet = executeQuery(generateEgoCoPIquery(this.egoURI), this.dataSource);
-	
 		after = System.currentTimeMillis();
 
 		log.debug("Time taken to execute the SELECT queries is in milliseconds: " + (after - before));
 
-	return createQueryResult(resultSet);
+		data = createQueryResult(resultSet);
+
+		CollaborationDataCacheEntry newEntry = new CollaborationDataCacheEntry();
+
+		newEntry.uri = this.egoURI;
+		newEntry.data = data;
+		newEntry.creationTime = newEntry.accessTime = new Date().getTime();
+
+		// Remove dead entries
+		expireCache();
+
+		// Cache the new entry
+		collaborationDataCache.put(this.egoURI, newEntry);
+		return data;
+	}
+
+	private synchronized void expireCache() {
+		for (String key : collaborationDataCache.keySet()) {
+			CollaborationDataCacheEntry entry = collaborationDataCache.get(key);
+			if (entry != null && entry.hasExpired()) {
+				collaborationDataCache.remove(key);
+			}
+		}
+	}
+
+	private static final Map<String, CollaborationDataCacheEntry> collaborationDataCache = new ConcurrentHashMap<String, CollaborationDataCacheEntry>();
+
+	private static class CollaborationDataCacheEntry {
+		String uri;
+		CollaborationData data;
+		long creationTime;
+		long accessTime;
+
+		boolean hasExpired() {
+			long now = new Date().getTime();
+
+			// If it's older than five minutes, and it hasn't *just* been accessed, it's expired
+			if (creationTime < (now - 300000L) && accessTime < (now - 3000L)) {
+				return true;
+			}
+
+			// Otherwise, if it is more than 30 seconds old, expire it
+			return accessTime < (now - 30000L);
+		}
 	}