build checksum only from attributes

src/main/java/org/appng/tomcat/session/SessionData.java

@@ -16,7 +16,6 @@
 package org.appng.tomcat.session;
 
 import java.io.Serializable;
-import java.util.Arrays;
 
 /**
  * Used to persist the binary representation of {@link org.apache.catalina.Session}.
@@ -28,11 +27,11 @@ public class SessionData implements Serializable {
 	private final byte[] data;
 	private final int checksum;
 
-	public SessionData(String id, String site, byte[] data) {
+	public SessionData(String id, String site, byte[] data, int checksum) {
 		this.id = id;
 		this.site = site;
 		this.data = data;
-		this.checksum = Arrays.hashCode(data);
+		this.checksum = checksum;
 	}
 
 	public String getSite() {

src/main/java/org/appng/tomcat/session/hazelcast/HazelcastSession.java

@@ -15,12 +15,17 @@
  */
 package org.appng.tomcat.session.hazelcast;
 
+import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.security.Principal;
+import java.util.Arrays;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.Map;
 
 import org.apache.catalina.Manager;
 import org.apache.catalina.Session;
@@ -34,7 +39,7 @@ public class HazelcastSession extends org.apache.catalina.session.StandardSessio
 
 	private static String DIRTY_FLAG = "__changed__";
 	private static final long serialVersionUID = -5219705900405324572L;
-	protected transient boolean dirty = false;
+	protected volatile transient boolean dirty = false;
 
 	public HazelcastSession(Manager manager) {
 		super(manager);
@@ -81,6 +86,25 @@ public SessionData serialize() throws IOException {
 		return serialize(null);
 	}
 
+	public int checksum() throws IOException {
+		Map<String, Object> attributes = new HashMap<String, Object>();
+		for (Enumeration<String> enumerator = getAttributeNames(); enumerator.hasMoreElements();) {
+			String key = enumerator.nextElement();
+			if (!DIRTY_FLAG.equals(key)) {
+				attributes.put(key, getAttribute(key));
+			}
+		}
+
+		try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
+				ObjectOutputStream oos = new ObjectOutputStream(new BufferedOutputStream(bos));) {
+			oos.writeUnshared(attributes);
+			oos.flush();
+			bos.flush();
+			int checksum = Arrays.hashCode(bos.toByteArray());
+			return checksum;
+		}
+	}
+
 	public SessionData serialize(String alternativeSiteName) throws IOException {
 		try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
 				ObjectOutputStream oos = new ObjectOutputStream(bos)) {
@@ -89,7 +113,7 @@ public SessionData serialize(String alternativeSiteName) throws IOException {
 			oos.flush();
 			bos.flush();
 			String siteName = null == alternativeSiteName ? Utils.getSiteName(this) : alternativeSiteName;
-			return new SessionData(getId(), siteName, bos.toByteArray());
+			return new SessionData(getId(), siteName, bos.toByteArray(), checksum());
 		}
 	}
 
@@ -100,8 +124,8 @@ public static HazelcastSession create(Manager manager, SessionData sessionData)
 			HazelcastSession session = (HazelcastSession) manager.createEmptySession();
 			session.readObjectData(ois);
 			session.access();
-			session.endAccess();
 			session.setClean();
+			manager.add(session);
 			return session;
 		}
 	}

src/main/java/org/appng/tomcat/session/hazelcast/v2/HazelcastManager.java

@@ -17,6 +17,7 @@
 
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.Locale;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.catalina.LifecycleException;
@@ -35,6 +36,7 @@
 
 public class HazelcastManager extends ManagerBase {
 
+	private static final double NANOS_TO_MILLIS = 1000000d;
 	private final Log log = Utils.getLog(HazelcastManager.class);
 	private String configFile = "WEB-INF/classes/hazelcast.xml";
 	private String mapName = "tomcat.sessions";
@@ -86,17 +88,21 @@ boolean commit(Session session) throws IOException {
 
 	boolean commit(Session session, String alternativeSiteName) throws IOException {
 		HazelcastSession hzSession = HazelcastSession.class.cast(session);
-		long start = System.currentTimeMillis();
-		SessionData currentSessionData = null;
-		if (hzSession.isDirty() || getPersistentSessions().get(session.getId())
-				.checksum() != (currentSessionData = hzSession.serialize(alternativeSiteName)).checksum()) {
-			SessionData sessionData = null == currentSessionData ? hzSession.serialize() : currentSessionData;
+		long start = System.nanoTime();
+		int oldChecksum = -1;
+		boolean sessionDirty = false;
+		if ((sessionDirty = hzSession.isDirty())
+				|| (oldChecksum = getPersistentSessions().get(session.getId()).checksum()) != hzSession.checksum()) {
+			SessionData sessionData = hzSession.serialize(alternativeSiteName);
 			getPersistentSessions().set(session.getId(), sessionData);
 			if (log.isDebugEnabled()) {
-				log.debug(String.format("Saved %s in %dms", sessionData, System.currentTimeMillis() - start));
+				String reason = sessionDirty ? "dirty-flag was set" : String.format("checksum <> %s", oldChecksum);
+				log.debug(String.format(Locale.ENGLISH, "Saved %s (%s) in %.2fms", sessionData, reason,
+						((System.nanoTime() - start)) / NANOS_TO_MILLIS));
 			}
 			return true;
-
+		} else if (log.isTraceEnabled()) {
+			log.trace(String.format("No changes in %s", session.getId()));
 		}
 		return false;
 	}
@@ -105,11 +111,9 @@ boolean commit(Session session, String alternativeSiteName) throws IOException {
 	public HazelcastSession findSession(String id) throws IOException {
 		HazelcastSession session = (HazelcastSession) super.findSession(id);
 		if (null == session) {
-
-			long start = System.currentTimeMillis();
-
-			// the calls are performed in a pessimistic lock block to prevent concurrency problems whilst finding
-			// sessions
+			long start = System.nanoTime();
+			// the calls are performed in a pessimistic lock block to prevent
+			// concurrency problems whilst finding sessions
 			getPersistentSessions().lock(id);
 			try {
 				SessionData sessionData = getPersistentSessions().get(id);
@@ -121,10 +125,9 @@ public HazelcastSession findSession(String id) throws IOException {
 					try {
 						session = HazelcastSession.create(this, sessionData);
 						if (log.isDebugEnabled()) {
-							log.debug(String.format("Loaded %s in %dms", sessionData,
-									System.currentTimeMillis() - start));
+							log.debug(String.format(Locale.ENGLISH, "Loaded %s in %.2fms", sessionData,
+									((System.nanoTime() - start)) / NANOS_TO_MILLIS));
 						}
-						add(session);
 					} catch (ClassNotFoundException e) {
 						log.error("Error loading session" + id, e);
 					}
@@ -134,7 +137,6 @@ public HazelcastSession findSession(String id) throws IOException {
 			}
 		} else {
 			session.access();
-			session.endAccess();
 		}
 		return session;
 	}

src/test/java/org/appng/tomcat/session/hazelcast/v2/HazelStoreIT.java

@@ -56,26 +56,38 @@ public void test() throws Exception {
 		session.setValid(true);
 		session.setCreationTime(System.currentTimeMillis());
 
+		int checkSum1 = session.checksum();
+
 		Assert.assertFalse(session.isDirty());
 		session.setAttribute("foo", "test");
 		HashMap<String, String> map = new HashMap<String, String>();
 		session.setAttribute("amap", map);
 		session.setAttribute("metaData", new MetaData());
+
+		int checkSum2 = session.checksum();
+		Assert.assertNotEquals(checkSum1, checkSum2);
+
 		Assert.assertTrue(session.isDirty());
 		Assert.assertTrue(manager.commit(session));
 		Assert.assertFalse(session.isDirty());
 		Assert.assertFalse(manager.commit(session));
 
 		SessionData original = session.serialize();
-		int checksum = original.checksum();
+		int checksum3 = original.checksum();
+
+		Assert.assertEquals(checkSum2, checksum3);
+
 		map.put("foo", "test");
 		SessionData modified = session.serialize();
-		int newChecksum = modified.checksum();
-		Assert.assertNotEquals(checksum, newChecksum);
+		int checksum4 = modified.checksum();
+		Assert.assertNotEquals(checksum3, checksum4);
 		Assert.assertTrue(manager.commit(session));
 
+		long accessedBefore = session.getThisAccessedTimeInternal();
 		HazelcastSession loaded = manager.findSession(session.getId());
 		Assert.assertEquals(session, loaded);
+		long accessedAfter = session.getThisAccessedTimeInternal();
+		Assert.assertNotEquals(accessedBefore, accessedAfter);
 
 		Assert.assertEquals(1, manager.getActiveSessions());
 		manager.removeLocal(session);
@@ -152,6 +164,7 @@ public void sessionCreated(HttpSessionEvent se) {
 
 	@BeforeClass
 	public static void setup() throws LifecycleException {
+
 		context = new StandardContext();
 
 		manager = new HazelcastManager();