Add ApplicationContextMembershipListener implementation and extension of MembershipListenerAdapter to adapt the Spring ApplicationContext to handle peer member departed and joined membership events.

spring-geode/src/main/java/org/springframework/geode/distributed/event/ApplicationContextMembershipListener.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2020 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
+ *
+ *     https://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.geode.distributed.event;
+
+import org.apache.geode.distributed.DistributedMember;
+import org.apache.geode.distributed.DistributedSystem;
+
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.geode.distributed.event.support.MemberDepartedEvent;
+import org.springframework.geode.distributed.event.support.MemberJoinedEvent;
+import org.springframework.lang.NonNull;
+import org.springframework.util.Assert;
+
+/**
+ * The {@link ApplicationContextMembershipListener} class is an extension of {@link MembershipListenerAdapter} used to
+ * adapt the {@link ConfigurableApplicationContext} to handle and process {@link MembershipEvent membership events},
+ * and specifically {@link MemberDepartedEvent} and {@link MemberJoinedEvent}, by
+ * {@link ConfigurableApplicationContext#close() closing} and {@link ConfigurableApplicationContext#refresh() refreshing}
+ * the {@link ConfigurableApplicationContext} when the {@link DistributedMember peer member} departs and joins the
+ * {@link DistributedSystem cluster}.
+ *
+ * @author John Blum
+ * @see org.apache.geode.distributed.DistributedMember
+ * @see org.apache.geode.distributed.DistributedSystem
+ * @see org.springframework.context.ConfigurableApplicationContext
+ * @see org.springframework.geode.distributed.event.support.MemberDepartedEvent
+ * @see org.springframework.geode.distributed.event.support.MemberJoinedEvent
+ * @since 1.3.0
+ */
+public class ApplicationContextMembershipListener
+		extends MembershipListenerAdapter<ApplicationContextMembershipListener> {
+
+	private final ConfigurableApplicationContext applicationContext;
+
+	/**
+	 * Constructs a new instance of {@link ConfigurableApplicationContext} initialized with
+	 * the given {@link ConfigurableApplicationContext}.
+	 *
+	 * @param applicationContext configured {@link ConfigurableApplicationContext}; must not be {@literal null}.
+	 * @throws IllegalArgumentException if {@link ConfigurableApplicationContext} is {@literal null}.
+	 * @see org.springframework.context.ConfigurableApplicationContext
+	 */
+	public ApplicationContextMembershipListener(@NonNull ConfigurableApplicationContext applicationContext) {
+
+		Assert.notNull(applicationContext, "ConfigurableApplicationContext must not be null");
+
+		this.applicationContext = applicationContext;
+	}
+
+	/**
+	 * Returns a reference to the configured {@link ConfigurableApplicationContext}.
+	 *
+	 * @return a reference to the configured {@link ConfigurableApplicationContext}.
+	 * @see org.springframework.context.ConfigurableApplicationContext
+	 */
+	protected @NonNull ConfigurableApplicationContext getApplicationContext() {
+		return this.applicationContext;
+	}
+
+	/**
+	 * Handles the {@link MembershipEvent membership event} when a {@link DistributedMember peer member}
+	 * departs from the {@link DistributedSystem cluster} by calling {@link ConfigurableApplicationContext#close()}.
+	 *
+	 * @param event {@link MemberDepartedEvent} to handle.
+	 * @see org.springframework.geode.distributed.event.support.MemberDepartedEvent
+	 * @see org.springframework.context.ConfigurableApplicationContext#close()
+	 */
+	@Override
+	public void handleMemberDeparted(MemberDepartedEvent event) {
+		getApplicationContext().close();
+	}
+
+	/**
+	 * Handles the {@link MembershipEvent membership event} when a {@link DistributedMember peer member}
+	 * joins the {@link DistributedSystem cluster} by calling {@link ConfigurableApplicationContext#refresh()}.
+	 *
+	 * @param event {@link MemberJoinedEvent} to handle.
+	 * @see org.springframework.geode.distributed.event.support.MemberJoinedEvent
+	 * @see org.springframework.context.ConfigurableApplicationContext#refresh()
+	 */
+	@Override
+	public void handleMemberJoined(MemberJoinedEvent event) {
+		getApplicationContext().refresh();
+	}
+}