Polish embedded tomcat classes

Extract some methods to aid readability.

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/ServletContextInitializerLifecycleListener.java

@@ -37,6 +37,7 @@ public class ServletContextInitializerLifecycleListener implements LifecycleList
 			.getLog(ServletContextInitializerLifecycleListener.class);
 
 	private final ServletContextInitializer[] initializers;
+
 	private Exception startUpException;
 
 	/**

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainer.java

@@ -24,7 +24,6 @@ import org.apache.catalina.Container;
 import org.apache.catalina.Engine;
 import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
-import org.apache.catalina.Server;
 import org.apache.catalina.Service;
 import org.apache.catalina.connector.Connector;
 import org.apache.catalina.startup.Tomcat;
@@ -77,38 +76,64 @@ public class TomcatEmbeddedServletContainer implements EmbeddedServletContainer
 
 	private synchronized void initialize() throws EmbeddedServletContainerException {
 		try {
-			Server server = this.tomcat.getServer();
+			addInstanceIdToEngineName();
+
+			// Remove service connectors to that protocol binding doesn't happen yet
+			removeServiceConnectors();
+
+			// Start the server to trigger initialization listeners
+			this.tomcat.start();
+
+			// We can re-throw failure exception directly in the main thread
+			rethrowDeferredStartupExceptions();
+
+			// Unlike Jetty, all Tomcat threads are daemon threads. We create a
+			// blocking non-daemon to stop immediate shutdown
+			startDaemonAwaitThread();
+
+			if (LifecycleState.FAILED.equals(this.tomcat.getConnector().getState())) {
+				this.tomcat.stop();
+				throw new IllegalStateException("Tomcat connector in failed state");
+			}
+		}
+		catch (Exception ex) {
+			throw new EmbeddedServletContainerException(
+					"Unable to start embedded Tomcat", ex);
+		}
+	}
+
+	private void addInstanceIdToEngineName() {
 		int instanceId = containerCounter.incrementAndGet();
 		if (instanceId > 0) {
 			Engine engine = this.tomcat.getEngine();
 			engine.setName(engine.getName() + "-" + instanceId);
 		}
+	}
 
-			// Remove service connectors to that protocol binding doesn't happen yet
-			for (Service service : server.findServices()) {
+	private void removeServiceConnectors() {
+		for (Service service : this.tomcat.getServer().findServices()) {
 			Connector[] connectors = service.findConnectors().clone();
 			this.serviceConnectors.put(service, connectors);
 			for (Connector connector : connectors) {
 				service.removeConnector(connector);
 			}
 		}
+	}
 
-			// Start the server to trigger initialization listeners
-			this.tomcat.start();
-
+	private void rethrowDeferredStartupExceptions() throws Exception {
 		Container[] children = this.tomcat.getHost().findChildren();
 		for (Container container : children) {
 			if (container instanceof TomcatEmbeddedContext) {
-					Exception exception = ((TomcatEmbeddedContext) container)
-							.getStarter().getStartUpException();
+				Exception exception = ((TomcatEmbeddedContext) container).getStarter()
+						.getStartUpException();
 				if (exception != null) {
 					throw exception;
 				}
 			}
 		}
+	}
 
-			// Unlike Jetty, all Tomcat threads are daemon threads. We create a
-			// blocking non-daemon to stop immediate shutdown
+	private void startDaemonAwaitThread() {
 		Thread awaitThread = new Thread("container-" + (containerCounter.get())) {
 			@Override
 			public void run() {
@@ -117,20 +142,18 @@ public class TomcatEmbeddedServletContainer implements EmbeddedServletContainer
 		};
 		awaitThread.setDaemon(false);
 		awaitThread.start();
-			if (LifecycleState.FAILED.equals(this.tomcat.getConnector().getState())) {
-				this.tomcat.stop();
-				throw new IllegalStateException("Tomcat connector in failed state");
-			}
-		}
-		catch (Exception ex) {
-			throw new EmbeddedServletContainerException(
-					"Unable to start embedded Tomcat", ex);
-		}
 	}
 
 	@Override
 	public void start() throws EmbeddedServletContainerException {
-		// Add the previously removed connectors (also starting them)
+		addPreviouslyRemovedConnectors();
+		Connector connector = this.tomcat.getConnector();
+		if (connector != null && this.autoStart) {
+			startConnector(connector);
+		}
+	}
+
+	private void addPreviouslyRemovedConnectors() {
 		Service[] services = this.tomcat.getServer().findServices();
 		for (Service service : services) {
 			Connector[] connectors = this.serviceConnectors.get(service);
@@ -138,21 +161,30 @@ public class TomcatEmbeddedServletContainer implements EmbeddedServletContainer
 				for (Connector connector : connectors) {
 					service.addConnector(connector);
 					if (!this.autoStart) {
-						unbind(connector);
+						stopProtocolHandler(connector);
 					}
 				}
 				this.serviceConnectors.remove(service);
 			}
 		}
-		Connector connector = this.tomcat.getConnector();
-		if (connector != null && this.autoStart) {
+	}
+
+	private void stopProtocolHandler(Connector connector) {
+		try {
+			connector.getProtocolHandler().stop();
+		}
+		catch (Exception ex) {
+			this.logger.error("Cannot pause connector: ", ex);
+		}
+	}
+
+	private void startConnector(Connector connector) {
 		try {
 			for (Container child : this.tomcat.getHost().findChildren()) {
 				if (child instanceof TomcatEmbeddedContext) {
 					((TomcatEmbeddedContext) child).deferredLoadOnStartup();
 				}
 			}
-				connector.getProtocolHandler().start();
 			logPorts();
 		}
 		catch (Exception ex) {
@@ -161,16 +193,6 @@ public class TomcatEmbeddedServletContainer implements EmbeddedServletContainer
 					"Unable to start embedded Tomcat connectors", ex);
 		}
 	}
-	}
-
-	private void unbind(Connector connector) {
-		try {
-			connector.getProtocolHandler().stop();
-		}
-		catch (Exception ex) {
-			this.logger.error("Cannot pause connector: ", ex);
-		}
-	}
 
 	Map<Service, Connector[]> getServiceConnectors() {
 		return this.serviceConnectors;