Add ServerHttpRequest & ServerHttpResponse

This commit introduces HTTP request and response abstractions along
with Servlet-based implementations similar to the ones in the http
package of spring-web but using Reactive Streams.

In turn HttpHandler now accepts the request and response types and
returns Publisher<Void> that reflects the end of handling.

The write method on the response also returns Publisher<Void> allowing
deferred writing. At the moment however the underlying Servlet 3.1
support only supports a single publisher after which the connection
is closed.

Only simple byte[] is supported for reading and writing.

spring-web-reactive/src/test/java/org/springframework/reactive/web/AbstractHttpHandlerIntegrationTestCase.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.reactive.web.servlet;
+package org.springframework.reactive.web;
 
 import java.net.URI;
 import java.util.Random;
@@ -29,7 +29,7 @@ import org.springframework.web.client.RestTemplate;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 
-public abstract class AbstractHttpHandlerServletIntegrationTestCase {
+public abstract class AbstractHttpHandlerIntegrationTestCase {
 
 	private static final int REQUEST_SIZE = 4096 * 3;
 

spring-web-reactive/src/test/java/org/springframework/reactive/web/CountingHttpHandler.java

@@ -30,8 +30,8 @@ public class CountingHttpHandler implements HttpHandler {
 	private static final Log logger = LogFactory.getLog(CountingHttpHandler.class);
 
 	@Override
-	public Publisher<byte[]> handle(Publisher<byte[]> request) {
-		request.subscribe(new Subscriber<byte[]>() {
+	public Publisher<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
+		request.getBody().subscribe(new Subscriber<byte[]>() {
 			private Subscription subscription;
 
 			private int byteCount = 0;

spring-web-reactive/src/test/java/org/springframework/reactive/web/EchoHandler.java

@@ -24,7 +24,7 @@ import org.reactivestreams.Publisher;
 public class EchoHandler implements HttpHandler {
 
 	@Override
-	public Publisher<byte[]> handle(Publisher<byte[]> request) {
-		return request;
+	public Publisher<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
+		return response.writeWith(request.getBody());
 	}
 }

spring-web-reactive/src/test/java/org/springframework/reactive/web/servlet/HttpHandlerJettyIntegrationTests.java

@@ -23,13 +23,14 @@ import org.eclipse.jetty.servlet.ServletHolder;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
+import org.springframework.reactive.web.AbstractHttpHandlerIntegrationTestCase;
 import org.springframework.reactive.web.EchoHandler;
 
 /**
  * @author Arjen Poutsma
  */
-public class HttpHandlerServletJettyIntegrationTests
-		extends AbstractHttpHandlerServletIntegrationTestCase {
+public class HttpHandlerJettyIntegrationTests
+		extends AbstractHttpHandlerIntegrationTestCase {
 
 	private static Server jettyServer;
 

spring-web-reactive/src/test/java/org/springframework/reactive/web/servlet/HttpHandlerTomcatIntegrationTests.java

@@ -24,12 +24,13 @@ import org.apache.catalina.startup.Tomcat;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
+import org.springframework.reactive.web.AbstractHttpHandlerIntegrationTestCase;
 import org.springframework.reactive.web.EchoHandler;
 
 /**
  * @author Arjen Poutsma
  */
-public class HttpHandlerServletTomcatIntegrationTests extends AbstractHttpHandlerServletIntegrationTestCase {
+public class HttpHandlerTomcatIntegrationTests extends AbstractHttpHandlerIntegrationTestCase {
 
 	private static Tomcat tomcatServer;