Add TomcatConnectorCustomizer

... and ServerProperties.Tomcat.maxThreads to conveniently
limit the thread pool size in the Connector.

spring-boot/src/main/java/org/springframework/boot/context/embedded/properties/ServerProperties.java

@@ -22,12 +22,16 @@ import java.net.InetAddress;
 import javax.validation.constraints.NotNull;
 
 import org.apache.catalina.Context;
+import org.apache.catalina.connector.Connector;
 import org.apache.catalina.valves.AccessLogValve;
 import org.apache.catalina.valves.RemoteIpValve;
+import org.apache.coyote.AbstractProtocol;
+import org.apache.coyote.ProtocolHandler;
 import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
+import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
 import org.springframework.boot.context.embedded.tomcat.TomcatContextCustomizer;
 import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
 import org.springframework.boot.context.properties.ConfigurationProperties;
@@ -119,6 +123,16 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 
 		private int backgroundProcessorDelay = 30; // seconds
 
+		private int maxThreads = 0; // Number of threads in protocol handler
+
+		public int getMaxThreads() {
+			return this.maxThreads;
+		}
+
+		public void setMaxThreads(int maxThreads) {
+			this.maxThreads = maxThreads;
+		}
+
 		public boolean getAccessLogEnabled() {
 			return this.accessLogEnabled;
 		}
@@ -189,6 +203,19 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 				factory.addContextValves(valve);
 			}
 
+			if (this.maxThreads > 0) {
+				factory.addConnectorCustomizers(new TomcatConnectorCustomizer() {
+					@Override
+					public void customize(Connector connector) {
+						ProtocolHandler handler = connector.getProtocolHandler();
+						if (handler instanceof AbstractProtocol) {
+							AbstractProtocol protocol = (AbstractProtocol) handler;
+							protocol.setMaxThreads(Tomcat.this.maxThreads);
+						}
+					}
+				});
+			}
+
 			if (this.accessLogEnabled) {
 				AccessLogValve valve = new AccessLogValve();
 				String accessLogPattern = getAccessLogPattern();
@@ -202,7 +229,6 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 				factory.addContextValves(valve);
 			}
 		}
-
 	}
 
 }

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

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2013 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.boot.context.embedded.tomcat;
+
+import org.apache.catalina.connector.Connector;
+
+/**
+ * @author Dave Syer
+ */
+public interface TomcatConnectorCustomizer {
+
+	/**
+	 * @param connector the connector to customize
+	 */
+	void customize(Connector connector);
+
+}

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

@@ -84,6 +84,8 @@ public class TomcatEmbeddedServletContainerFactory extends
 
 	private List<TomcatContextCustomizer> tomcatContextCustomizers = new ArrayList<TomcatContextCustomizer>();
 
+	private List<TomcatConnectorCustomizer> tomcatConnectorCustomizers = new ArrayList<TomcatConnectorCustomizer>();
+
 	private ResourceLoader resourceLoader;
 
 	private String protocol = DEFAULT_PROTOCOL;
@@ -203,6 +205,9 @@ public class TomcatEmbeddedServletContainerFactory extends
 		// If ApplicationContext is slow to start we want Tomcat not to bind to the socket
 		// prematurely...
 		connector.setProperty("bindOnInit", "false");
+		for (TomcatConnectorCustomizer customizer : this.tomcatConnectorCustomizers) {
+			customizer.customize(connector);
+		}
 	}
 
 	/**
@@ -384,6 +389,40 @@ public class TomcatEmbeddedServletContainerFactory extends
 		this.tomcatContextCustomizers.addAll(Arrays.asList(tomcatContextCustomizers));
 	}
 
+	/**
+	 * Set {@link TomcatConnectorCustomizer}s that should be applied to the Tomcat
+	 * {@link Connector} . Calling this method will replace any existing customizers.
+	 * @param tomcatConnectorCustomizers the customizers to set
+	 */
+	public void setTomcatConnectorCustomizers(
+			Collection<? extends TomcatConnectorCustomizer> tomcatConnectorCustomizers) {
+		Assert.notNull(this.contextLifecycleListeners,
+				"TomcatConnectorCustomizer must not be null");
+		this.tomcatConnectorCustomizers = new ArrayList<TomcatConnectorCustomizer>(
+				tomcatConnectorCustomizers);
+	}
+
+	/**
+	 * Add {@link TomcatContextCustomizer}s that should be added to the Tomcat
+	 * {@link Connector}.
+	 * @param tomcatConnectorCustomizers the customizers to add
+	 */
+	public void addConnectorCustomizers(
+			TomcatConnectorCustomizer... tomcatConnectorCustomizers) {
+		Assert.notNull(this.tomcatContextCustomizers,
+				"TomcatConnectorCustomizer must not be null");
+		this.tomcatConnectorCustomizers.addAll(Arrays.asList(tomcatConnectorCustomizers));
+	}
+
+	/**
+	 * Returns a mutable collection of the {@link TomcatContextCustomizer}s that will be
+	 * applied to the Tomcat {@link Context} .
+	 * @return the tomcatContextCustomizers the listeners that will be applied
+	 */
+	public Collection<TomcatConnectorCustomizer> getTomcatConnectorCustomizers() {
+		return this.tomcatConnectorCustomizers;
+	}
+
 	private static class TomcatErrorPage {
 
 		private String location;

spring-boot/src/test/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactoryTests.java

@@ -22,6 +22,7 @@ import java.util.concurrent.TimeUnit;
 import org.apache.catalina.Context;
 import org.apache.catalina.LifecycleEvent;
 import org.apache.catalina.LifecycleListener;
+import org.apache.catalina.connector.Connector;
 import org.apache.catalina.startup.Tomcat;
 import org.junit.Test;
 import org.mockito.InOrder;
@@ -80,6 +81,22 @@ public class TomcatEmbeddedServletContainerFactoryTests extends
 		}
 	}
 
+	@Test
+	public void tomcatConnectorCustomizers() throws Exception {
+		TomcatEmbeddedServletContainerFactory factory = getFactory();
+		TomcatConnectorCustomizer[] listeners = new TomcatConnectorCustomizer[4];
+		for (int i = 0; i < listeners.length; i++) {
+			listeners[i] = mock(TomcatConnectorCustomizer.class);
+		}
+		factory.setTomcatConnectorCustomizers(Arrays.asList(listeners[0], listeners[1]));
+		factory.addConnectorCustomizers(listeners[2], listeners[3]);
+		this.container = factory.getEmbeddedServletContainer();
+		InOrder ordered = inOrder((Object[]) listeners);
+		for (TomcatConnectorCustomizer listener : listeners) {
+			ordered.verify(listener).customize((Connector) anyObject());
+		}
+	}
+
 	@Test
 	public void sessionTimeout() throws Exception {
 		TomcatEmbeddedServletContainerFactory factory = getFactory();