Fix SubscriptionTask leaving open connections

DATAREDIS-124

- Close connection when SubscriptionTask is canceled and subscribing thread is unblocked

- Ensure non-blocking Lettuce and SRP only attempt
to close subscriptions if active

- Cleanup unecessary synchronization between
SubscriptionTask methods, now that connection is
no longer set to null

- Cleanup unused monitor notify when SubscriptionTask thread ends

src/test/java/org/springframework/data/redis/listener/SubscriptionConnectionTests.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright 2011-2013 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.data.redis.listener;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.core.task.SimpleAsyncTaskExecutor;
+import org.springframework.core.task.SyncTaskExecutor;
+import org.springframework.data.redis.SettingsUtils;
+import org.springframework.data.redis.connection.MessageListener;
+import org.springframework.data.redis.connection.RedisConnection;
+import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
+import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
+
+/**
+ * Integration tests confirming that {@link RedisMessageListenerContainer}
+ * closes connections after unsubscribing
+ *
+ * @author Jennifer Hickey
+ *
+ */
+public class SubscriptionConnectionTests {
+
+	private static final String CHANNEL = "pubsub::test";
+
+	private JedisConnectionFactory connectionFactory;
+
+	private List<RedisMessageListenerContainer> containers = new ArrayList<RedisMessageListenerContainer>();
+
+	private final Object handler = new Object() {
+		@SuppressWarnings("unused")
+		public void handleMessage(String message) {
+			System.out.println(message);
+		}
+	};
+
+	@Before
+	public void setUp() {
+		connectionFactory = new JedisConnectionFactory();
+		connectionFactory.setUsePool(true);
+		connectionFactory.setPort(SettingsUtils.getPort());
+		connectionFactory.setHostName(SettingsUtils.getHost());
+		connectionFactory.setDatabase(2);
+		connectionFactory.afterPropertiesSet();
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		for (RedisMessageListenerContainer container : containers) {
+			if (container.isActive()) {
+				container.destroy();
+			}
+		}
+		connectionFactory.destroy();
+	}
+
+	@Test
+	public void testStopMessageListenerContainers() throws Exception {
+		// Grab all 8 connections from the pool. They should be released on
+		// container stop
+		for (int i = 0; i < 8; i++) {
+			RedisMessageListenerContainer container = new RedisMessageListenerContainer();
+			container.setConnectionFactory(connectionFactory);
+			container.setBeanName("container" + i);
+			container.addMessageListener(new MessageListenerAdapter(handler),
+					Arrays.asList(new ChannelTopic(CHANNEL)));
+			container.setTaskExecutor(new SyncTaskExecutor());
+			container.setSubscriptionExecutor(new SimpleAsyncTaskExecutor());
+			container.afterPropertiesSet();
+			container.start();
+			container.stop();
+			containers.add(container);
+		}
+		// verify we can now get a connection from the pool
+		RedisConnection connection = connectionFactory.getConnection();
+		connection.close();
+	}
+
+	@Test
+	public void testRemoveLastListener() {
+		// Grab all 8 connections from the pool
+		MessageListener listener = new MessageListenerAdapter(handler);
+		for (int i = 0; i < 8; i++) {
+			RedisMessageListenerContainer container = new RedisMessageListenerContainer();
+			container.setConnectionFactory(connectionFactory);
+			container.setBeanName("container" + i);
+			container.addMessageListener(listener, Arrays.asList(new ChannelTopic(CHANNEL)));
+			container.setTaskExecutor(new SyncTaskExecutor());
+			container.setSubscriptionExecutor(new SimpleAsyncTaskExecutor());
+			container.afterPropertiesSet();
+			container.start();
+			containers.add(container);
+		}
+
+		// Removing the sole listener from the container should free up a
+		// connection
+		containers.get(0).removeMessageListener(listener);
+
+		// verify we can now get a connection from the pool
+		RedisConnection connection = connectionFactory.getConnection();
+		connection.close();
+	}
+
+	@Test
+	public void testStopListening() {
+		// Grab all 8 connections from the pool.
+		MessageListener listener = new MessageListenerAdapter(handler);
+		for (int i = 0; i < 8; i++) {
+			RedisMessageListenerContainer container = new RedisMessageListenerContainer();
+			container.setConnectionFactory(connectionFactory);
+			container.setBeanName("container" + i);
+			container.addMessageListener(listener, Arrays.asList(new ChannelTopic(CHANNEL)));
+			container.setTaskExecutor(new SyncTaskExecutor());
+			container.setSubscriptionExecutor(new SimpleAsyncTaskExecutor());
+			container.afterPropertiesSet();
+			container.start();
+			containers.add(container);
+		}
+
+		// Unsubscribe all listeners from all topics, freeing up a  connection
+		containers.get(0).removeMessageListener(null, Arrays.asList(new Topic[] {}));
+
+		// verify we can now get a connection from the pool
+		RedisConnection connection = connectionFactory.getConnection();
+		connection.close();
+	}
+
+}