Fixup documentation and samples.

samples/xml/gemfire-clientserver/src/main/java/sample/ClientServerReadyBeanPostProcessor.java

@@ -0,0 +1,154 @@
+/*
+ * 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 java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.apache.geode.cache.Region;
+import org.apache.geode.cache.client.Pool;
+import org.apache.geode.cache.client.PoolManager;
+import org.apache.geode.cache.client.internal.PoolImpl;
+import org.apache.geode.management.membership.ClientMembership;
+import org.apache.geode.management.membership.ClientMembershipEvent;
+import org.apache.geode.management.membership.ClientMembershipListenerAdapter;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.data.gemfire.config.xml.GemfireConstants;
+import org.springframework.session.data.gemfire.config.annotation.web.http.GemFireHttpSessionConfiguration;
+import org.springframework.util.Assert;
+
+public class ClientServerReadyBeanPostProcessor implements BeanPostProcessor {
+
+	private static final long DEFAULT_TIMEOUT = TimeUnit.SECONDS.toMillis(60);
+
+	private static final CountDownLatch LATCH = new CountDownLatch(1);
+
+	private static final String GEMFIRE_DEFAULT_POOL_NAME = "DEFAULT";
+
+	static {
+		ClientMembership.registerClientMembershipListener(
+			new ClientMembershipListenerAdapter() {
+				@Override
+				public void memberJoined(ClientMembershipEvent event) {
+					LATCH.countDown();
+				}
+			}
+		);
+	}
+
+	@Value("${spring.session.data.geode.cache.server.port:${application.geode.client-server.port:40404}}")
+	private int port;
+
+	@Value("${application.geode.client-server.host:localhost}")
+	private String host;
+
+	private final AtomicBoolean checkGemFireServerIsRunning = new AtomicBoolean(true);
+	private final AtomicReference<Pool> gemfirePool = new AtomicReference<Pool>(null);
+
+	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
+
+		if (shouldCheckWhetherGemFireServerIsRunning(bean, beanName)) {
+			try {
+				validateCacheClientNotified();
+				validateCacheClientSubscriptionQueueConnectionEstablished();
+			}
+			catch (InterruptedException e) {
+				Thread.currentThread().interrupt();
+			}
+		}
+
+		return bean;
+	}
+
+	private boolean shouldCheckWhetherGemFireServerIsRunning(Object bean, String beanName) {
+
+		return (isGemFireRegion(bean, beanName)
+			? this.checkGemFireServerIsRunning.compareAndSet(true, false)
+			: whenGemFirePool(bean, beanName));
+	}
+
+	private boolean isGemFireRegion(Object bean, String beanName) {
+
+		return (GemFireHttpSessionConfiguration.DEFAULT_SPRING_SESSION_GEMFIRE_REGION_NAME.equals(beanName)
+			|| bean instanceof Region);
+	}
+
+	private boolean whenGemFirePool(Object bean, String beanName) {
+
+		if (bean instanceof Pool) {
+			this.gemfirePool.compareAndSet(null, (Pool) bean);
+		}
+
+		return false;
+	}
+
+	private void validateCacheClientNotified() throws InterruptedException {
+
+		boolean didNotTimeout = LATCH.await(DEFAULT_TIMEOUT, TimeUnit.MILLISECONDS);
+
+		Assert.state(didNotTimeout, String.format(
+			"Apache Geode Cache Server failed to start on host [%s] and port [%d]", this.host, this.port));
+	}
+
+	@SuppressWarnings("all")
+	private void validateCacheClientSubscriptionQueueConnectionEstablished() throws InterruptedException {
+
+		boolean cacheClientSubscriptionQueueConnectionEstablished = false;
+
+		Pool pool = defaultIfNull(this.gemfirePool.get(),
+			GemfireConstants.DEFAULT_GEMFIRE_POOL_NAME, GEMFIRE_DEFAULT_POOL_NAME);
+
+		if (pool instanceof PoolImpl) {
+
+			long timeout = (System.currentTimeMillis() + DEFAULT_TIMEOUT);
+
+			while (System.currentTimeMillis() < timeout && !((PoolImpl) pool).isPrimaryUpdaterAlive()) {
+
+				synchronized (pool) {
+					TimeUnit.MILLISECONDS.timedWait(pool, 500L);
+				}
+
+			}
+
+			cacheClientSubscriptionQueueConnectionEstablished |=
+				((PoolImpl) pool).isPrimaryUpdaterAlive();
+		}
+
+		Assert.state(cacheClientSubscriptionQueueConnectionEstablished,
+			String.format("Cache client subscription queue connection not established; Geode Pool was [%s];"
+				+ " Geode Pool configuration was [locators = %s, servers = %s]",
+					pool, pool.getLocators(), pool.getServers()));
+	}
+
+	private Pool defaultIfNull(Pool pool, String... poolNames) {
+
+		for (String poolName : poolNames) {
+			pool = (pool != null ? pool : PoolManager.find(poolName));
+		}
+
+		return pool;
+	}
+
+	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+		return bean;
+	}
+}