Add support for eager commits, which copies and then commits the Session before saving.

Resolves gh-12.

spring-session-data-geode/src/main/java/org/springframework/session/data/gemfire/AbstractGemFireOperationsSessionRepository.java

@@ -106,6 +106,7 @@ public abstract class AbstractGemFireOperationsSessionRepository extends CacheLi
 		implements ApplicationEventPublisherAware, FindByIndexNameSessionRepository<Session>, InitializingBean {
 
 	private static final AtomicBoolean usingDataSerialization = new AtomicBoolean(false);
+	private static final AtomicBoolean usingEagerCommit = new AtomicBoolean(false);
 
 	private ApplicationEventPublisher applicationEventPublisher = event -> {};
 
@@ -275,6 +276,25 @@ public abstract class AbstractGemFireOperationsSessionRepository extends CacheLi
 		return usingDataSerialization.get();
 	}
 
+	/**
+	 * Set a condition to determine whether a {@link Session} is copied and committed before saving.
+	 *
+	 * @param useEagerCommit boolean to determine whether to copy and commit a {@link Session} before saving.
+	 */
+	@SuppressWarnings("unused")
+	public void setUseEagerCommit(boolean useEagerCommit) {
+		usingEagerCommit.set(useEagerCommit);
+	}
+
+	/**
+	 * Determines whether a {@link Session} is copied and committed before saving.
+	 *
+	 * @return a boolean value indicating whether a {@link Session} is copied and committed before saving.
+	 */
+	protected boolean isUsingEagerCommit() {
+		return usingEagerCommit.get();
+	}
+
 	/**
 	 * Callback method during Spring bean initialization that will capture the fully-qualified name
 	 * of the cache {@link Region} used to manage {@link Session} state and register this {@link SessionRepository}
@@ -677,6 +697,21 @@ public abstract class AbstractGemFireOperationsSessionRepository extends CacheLi
 				: new GemFireSession(session);
 		}
 
+		@SuppressWarnings("all")
+		public static GemFireSession copyCommitted(Session session) {
+
+			synchronized (session) {
+
+				GemFireSession sessionCopy = copy(session);
+
+				if (session instanceof GemFireSession) {
+					((GemFireSession) session).commit();
+				}
+
+				return sessionCopy;
+			}
+		}
+
 		@SuppressWarnings("unchecked")
 		public static <T extends GemFireSession> T from(Session session) {
 			return (T) (session instanceof GemFireSession ? session : copy(session));

spring-session-data-geode/src/main/java/org/springframework/session/data/gemfire/GemFireOperationsSessionRepository.java

@@ -166,14 +166,22 @@ public class GemFireOperationsSessionRepository extends AbstractGemFireOperation
 
 	/*private*/ void doSave(@NonNull Session session) {
 
-		// Save Session As GemFireSession
-		getTemplate().put(session.getId(), GemFireSession.from(session));
+		GemFireSession sessionToSave = isUsingEagerCommit()
+			? GemFireSession.copyCommitted(session)
+			: GemFireSession.from(session);
 
-		if (session instanceof GemFireSession) {
+		// Save Session As GemFireSession
+		getTemplate().put(session.getId(), sessionToSave);
+
+		if (isCommittable(session)) {
 			((GemFireSession) session).commit();
 		}
 	}
 
+	private boolean isCommittable(@Nullable Session session) {
+		return !isUsingEagerCommit() && session instanceof GemFireSession;
+	}
+
 	/**
 	 * Deletes (removes) any existing {@link Session} from GemFire. This operation
 	 * also results in a SessionDeletedEvent.