GH-172: Do not require local HZ instances

Fixes spring-projects/spring-integration-extensions#172

Since we can have an application based on the `HazelcastClient`, we don't need to require `Hazelcast.getAllHazelcastInstances()` be presented.

* Rework `HazelcastLocalInstanceRegistrar` to be able to accept external `HazelcastInstance` for `MultiMap` and `MembershipListener` registration
* If there is on local `Hazelcast.getAllHazelcastInstances()` just log a warn that we can't register `MembershipListener`
* Allow for `AbstractHazelcastMessageProducer` to accept events in the `CacheListeningPolicyType.SINGLE` mode when there is no local `Hazelcast.getAllHazelcastInstances()`

spring-integration-hazelcast/src/main/java/org/springframework/integration/hazelcast/HazelcastLocalInstanceRegistrar.java

@@ -19,6 +19,9 @@ package org.springframework.integration.hazelcast;
 import java.net.SocketAddress;
 import java.util.concurrent.locks.Lock;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.integration.hazelcast.listener.HazelcastMembershipListener;
 
@@ -33,10 +36,19 @@ import com.hazelcast.core.MultiMap;
  * membership updates.
  *
  * @author Eren Avsarogullari
+ * @author Artem Bilan
+ *
  * @since 1.0.0
  */
 public class HazelcastLocalInstanceRegistrar implements SmartInitializingSingleton {
 
+	private static final Log logger = LogFactory.getLog(HazelcastLocalInstanceRegistrar.class);
+
+	/**
+	 * The bean name for the {@link HazelcastLocalInstanceRegistrar} instance.
+	 */
+	public static final String BEAN_NAME = "hazelcastLocalInstanceRegistrar";
+
 	/**
 	 * The name for the Hazelcast MultiMap used for membership registration.
 	 */
@@ -48,15 +60,38 @@ public class HazelcastLocalInstanceRegistrar implements SmartInitializingSinglet
 	 */
 	public static final String SPRING_INTEGRATION_INTERNAL_CLUSTER_LOCK = "SPRING_INTEGRATION_INTERNAL_CLUSTER_LOCK";
 
+	private final HazelcastInstance hazelcastInstance;
+
+	/**
+	 * Construct {@link HazelcastLocalInstanceRegistrar} based on the local JVM {@link HazelcastInstance}s if any.
+	 */
+	public HazelcastLocalInstanceRegistrar() {
+		this.hazelcastInstance = null;
+	}
+
+	/**
+	 * Construct {@link HazelcastLocalInstanceRegistrar} based on the provided {@link HazelcastInstance}.
+	 * @param hazelcastInstance the {@link HazelcastInstance} to use.
+	 */
+	public HazelcastLocalInstanceRegistrar(HazelcastInstance hazelcastInstance) {
+		this.hazelcastInstance = hazelcastInstance;
+	}
+
 	@Override
 	public void afterSingletonsInstantiated() {
-		if (!Hazelcast.getAllHazelcastInstances().isEmpty()) {
-			HazelcastInstance hazelcastInstance = Hazelcast.getAllHazelcastInstances().iterator().next();
-			hazelcastInstance.getCluster().addMembershipListener(new HazelcastMembershipListener());
-			syncConfigurationMultiMap(hazelcastInstance);
+		if (this.hazelcastInstance == null) {
+			if (!Hazelcast.getAllHazelcastInstances().isEmpty()) {
+				HazelcastInstance hazelcastInstance = Hazelcast.getAllHazelcastInstances().iterator().next();
+				hazelcastInstance.getCluster().addMembershipListener(new HazelcastMembershipListener());
+				syncConfigurationMultiMap(hazelcastInstance);
+			}
+			else {
+				logger.warn("No HazelcastInstances for MembershipListener registration");
+			}
 		}
 		else {
-			throw new IllegalStateException("No Active Local Hazelcast Instance found.");
+			syncConfigurationMultiMap(this.hazelcastInstance);
+			this.hazelcastInstance.getCluster().addMembershipListener(new HazelcastMembershipListener());
 		}
 	}
 

spring-integration-hazelcast/src/main/java/org/springframework/integration/hazelcast/config/HazelcastIntegrationConfigurationInitializer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2017 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.
@@ -27,18 +27,17 @@ import org.springframework.integration.hazelcast.HazelcastLocalInstanceRegistrar
  * The Hazelcast Integration infrastructure {@code beanFactory} initializer.
  *
  * @author Eren Avsarogullari
+ * @author Artem Bilan
+ *
  * @since 1.0.0
  */
 public class HazelcastIntegrationConfigurationInitializer implements IntegrationConfigurationInitializer {
 
-	private static final String HAZELCAST_LOCAL_INSTANCE_REGISTRAR_BEAN_NAME =
-			HazelcastLocalInstanceRegistrar.class.getName();
-
 	@Override
 	public void initialize(ConfigurableListableBeanFactory beanFactory) throws BeansException {
 		BeanDefinitionRegistry beanDefinitionRegistry = (BeanDefinitionRegistry) beanFactory;
-		if (!beanDefinitionRegistry.containsBeanDefinition(HAZELCAST_LOCAL_INSTANCE_REGISTRAR_BEAN_NAME)) {
-			beanDefinitionRegistry.registerBeanDefinition(HAZELCAST_LOCAL_INSTANCE_REGISTRAR_BEAN_NAME,
+		if (!beanDefinitionRegistry.containsBeanDefinition(HazelcastLocalInstanceRegistrar.BEAN_NAME)) {
+			beanDefinitionRegistry.registerBeanDefinition(HazelcastLocalInstanceRegistrar.BEAN_NAME,
 					new RootBeanDefinition(HazelcastLocalInstanceRegistrar.class));
 		}
 	}

spring-integration-hazelcast/src/main/java/org/springframework/integration/hazelcast/inbound/AbstractHazelcastMessageProducer.java

@@ -48,6 +48,7 @@ import com.hazelcast.core.MultiMap;
  *
  * @author Eren Avsarogullari
  * @author Artem Bilan
+ *
  * @since 1.0.0
  */
 public abstract class AbstractHazelcastMessageProducer extends MessageProducerSupport {
@@ -116,10 +117,11 @@ public abstract class AbstractHazelcastMessageProducer extends MessageProducerSu
 		private boolean isEventAcceptable(final InetSocketAddress socketAddress) {
 			final Set<HazelcastInstance> hazelcastInstanceSet = Hazelcast.getAllHazelcastInstances();
 			final Set<SocketAddress> localSocketAddressesSet = getLocalSocketAddresses(hazelcastInstanceSet);
-			return (!localSocketAddressesSet.isEmpty())
-					&& (localSocketAddressesSet.contains(socketAddress) ||
-					isEventComingFromNonRegisteredHazelcastInstance(hazelcastInstanceSet.iterator().next(),
-							localSocketAddressesSet, socketAddress));
+			return localSocketAddressesSet.isEmpty() ||
+					(!localSocketAddressesSet.isEmpty()
+							&& (localSocketAddressesSet.contains(socketAddress) ||
+							isEventComingFromNonRegisteredHazelcastInstance(hazelcastInstanceSet.iterator().next(),
+									localSocketAddressesSet, socketAddress)));
 
 		}
 

spring-integration-hazelcast/src/test/java/org/springframework/integration/hazelcast/inbound/config/HazelcastIntegrationInboundTestConfiguration.java

@@ -24,6 +24,7 @@ import org.springframework.integration.channel.QueueChannel;
 import org.springframework.integration.config.EnableIntegration;
 import org.springframework.integration.hazelcast.DistributedSQLIterationType;
 import org.springframework.integration.hazelcast.HazelcastIntegrationTestUser;
+import org.springframework.integration.hazelcast.HazelcastLocalInstanceRegistrar;
 import org.springframework.integration.hazelcast.inbound.HazelcastClusterMonitorMessageProducer;
 import org.springframework.integration.hazelcast.inbound.HazelcastContinuousQueryMessageProducer;
 import org.springframework.integration.hazelcast.inbound.HazelcastDistributedSQLMessageSource;
@@ -215,6 +216,11 @@ public class HazelcastIntegrationInboundTestConfiguration {
 		return Hazelcast.newHazelcastInstance();
 	}
 
+	@Bean(HazelcastLocalInstanceRegistrar.BEAN_NAME)
+	public HazelcastLocalInstanceRegistrar hazelcastLocalInstanceRegistrar() {
+		return new HazelcastLocalInstanceRegistrar(testHazelcastInstance());
+	}
+
 	@Bean
 	public HazelcastEventDrivenMessageProducer hazelcastEventDrivenMessageProducer() {
 		final HazelcastEventDrivenMessageProducer producer =