Add HazelcastSessionRepository

This commit improves existing Hazelcast support, which is based on
MapSessionRepository, with dedicated HazelcastSessionRepository
that implements the FindByIndexNameSessionRepository contract.

Also a new hazelcast-spring-session module was added to provide
dependency management for Hazelcast support.

Fixes gh-544

samples/hazelcast-spring/src/main/java/sample/SessionConfig.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2014-2016 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 sample;
+
+import com.hazelcast.config.Config;
+import com.hazelcast.config.MapAttributeConfig;
+import com.hazelcast.config.MapIndexConfig;
+import com.hazelcast.config.SerializerConfig;
+import com.hazelcast.core.Hazelcast;
+import com.hazelcast.core.HazelcastInstance;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.session.hazelcast.HazelcastSessionRepository;
+import org.springframework.session.hazelcast.PrincipalNameExtractor;
+import org.springframework.session.hazelcast.config.annotation.web.http.EnableHazelcastHttpSession;
+import org.springframework.util.SocketUtils;
+
+// tag::class[]
+@EnableHazelcastHttpSession(maxInactiveIntervalInSeconds = 300)
+@Configuration
+public class SessionConfig {
+
+	@Bean(destroyMethod = "shutdown")
+	public HazelcastInstance hazelcastInstance() {
+		Config config = new Config();
+
+		int port = SocketUtils.findAvailableTcpPort();
+
+		config.getNetworkConfig()
+				.setPort(port);
+
+		System.out.println("Hazelcast port #: " + port);
+
+		SerializerConfig serializer = new SerializerConfig()
+				.setImplementation(new ObjectStreamSerializer())
+				.setTypeClass(Object.class);
+
+		config.getSerializationConfig()
+				.addSerializerConfig(serializer);
+
+		MapAttributeConfig attributeConfig = new MapAttributeConfig()
+				.setName(HazelcastSessionRepository.PRINCIPAL_NAME_ATTRIBUTE)
+				.setExtractor(PrincipalNameExtractor.class.getName());
+
+		config.getMapConfig("spring:session:sessions")
+				.addMapAttributeConfig(attributeConfig)
+				.addMapIndexConfig(new MapIndexConfig(
+						HazelcastSessionRepository.PRINCIPAL_NAME_ATTRIBUTE, false));
+
+		return Hazelcast.newHazelcastInstance(config);
+	}
+
+}
+// end::class[]