MapSessionRepository handles expried sessions

Fixes gh-31

spring-session/src/main/java/org/springframework/session/MapSessionRepository.java

@@ -62,6 +62,10 @@ public class MapSessionRepository implements SessionRepository<ExpiringSession>
         if(saved == null) {
             return null;
         }
+        if(saved.isExpired()) {
+            delete(saved.getId());
+            return null;
+        }
         MapSession result = new MapSession(saved);
         result.setLastAccessedTime(System.currentTimeMillis());
         return result;

spring-session/src/test/java/org/springframework/session/MapSessionRepositoryTests.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2002-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.session;
+
+import static org.fest.assertions.Assertions.assertThat;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class MapSessionRepositoryTests {
+    MapSessionRepository repository;
+
+    MapSession session;
+
+    @Before
+    public void setup() {
+        repository = new MapSessionRepository();
+        session = new MapSession();
+    }
+
+    @Test
+    public void getSessionExpired() {
+        session.setMaxInactiveInterval(1);
+        session.setLastAccessedTime(System.currentTimeMillis() - TimeUnit.MINUTES.toMillis(5));
+        repository.save(session);
+
+        assertThat(repository.getSession(session.getId())).isNull();
+    }
+
+}