Improve RouterFunction builder

This commit improves the RouterFunctions.Builder based on conversations
had during the weekly team meeting.

Issue: SPR-16953

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/RouterFunctionBuilderTests.java

@@ -23,8 +23,11 @@ import org.junit.Test;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 
 import static org.junit.Assert.*;
 
@@ -35,10 +38,11 @@ public class RouterFunctionBuilderTests {
 
 	@Test
 	public void route() {
-		RouterFunction<ServerResponse> route = RouterFunctions.builder()
-				.routeGet("/foo", request -> ServerResponse.ok().build())
-				.routePost(request -> ServerResponse.noContent().build())
+		RouterFunction<ServerResponse> route = RouterFunctions.route()
+				.GET("/foo", request -> ServerResponse.ok().build())
+				.POST("/", RequestPredicates.contentType(MediaType.TEXT_PLAIN), request -> ServerResponse.noContent().build())
 				.build();
+		System.out.println(route);
 
 		MockServerRequest fooRequest = MockServerRequest.builder().
 				method(HttpMethod.GET).
@@ -56,7 +60,8 @@ public class RouterFunctionBuilderTests {
 
 		MockServerRequest barRequest = MockServerRequest.builder().
 				method(HttpMethod.POST).
-				uri(URI.create("http://localhost"))
+				uri(URI.create("http://localhost/"))
+				.header("Content-Type", "text/plain")
 				.build();
 
 		responseMono = route.route(barRequest)
@@ -68,15 +73,65 @@ public class RouterFunctionBuilderTests {
 				.expectNext(204)
 				.verifyComplete();
 
+		MockServerRequest invalidRequest = MockServerRequest.builder().
+				method(HttpMethod.POST).
+				uri(URI.create("http://localhost/"))
+				.build();
+
+		responseMono = route.route(invalidRequest)
+				.flatMap(handlerFunction -> handlerFunction.handle(invalidRequest))
+				.map(ServerResponse::statusCode)
+				.map(HttpStatus::value);
+
+		StepVerifier.create(responseMono)
+				.verifyComplete();
+
+	}
+
+	@Test
+	public void resources() {
+		Resource resource = new ClassPathResource("/org/springframework/web/reactive/function/server/");
+		assertTrue(resource.exists());
+
+		RouterFunction<ServerResponse> route = RouterFunctions.route()
+				.resources("/resources/**", resource)
+				.build();
+
+		MockServerRequest resourceRequest = MockServerRequest.builder().
+				method(HttpMethod.GET).
+				uri(URI.create("http://localhost/resources/response.txt"))
+				.build();
+
+		Mono<Integer> responseMono = route.route(resourceRequest)
+				.flatMap(handlerFunction -> handlerFunction.handle(resourceRequest))
+				.map(ServerResponse::statusCode)
+				.map(HttpStatus::value);
+
+		StepVerifier.create(responseMono)
+				.expectNext(200)
+				.verifyComplete();
+
+		MockServerRequest invalidRequest = MockServerRequest.builder().
+				method(HttpMethod.POST).
+				uri(URI.create("http://localhost/resources/foo.txt"))
+				.build();
+
+		responseMono = route.route(invalidRequest)
+				.flatMap(handlerFunction -> handlerFunction.handle(invalidRequest))
+				.map(ServerResponse::statusCode)
+				.map(HttpStatus::value);
+
+		StepVerifier.create(responseMono)
+				.verifyComplete();
 	}
 
 	@Test
 	public void nest() {
-		RouterFunction<?> route = RouterFunctions.builder()
-				.nestPath("/foo", builder ->
-						builder.nestPath("/bar",
-								() -> RouterFunctions.builder()
-										.routeGet("/baz", request -> ServerResponse.ok().build())
+		RouterFunction<?> route = RouterFunctions.route()
+				.path("/foo", builder ->
+						builder.path("/bar",
+								() -> RouterFunctions.route()
+										.GET("/baz", request -> ServerResponse.ok().build())
 										.build()))
 				.build();
 
@@ -99,18 +154,18 @@ public class RouterFunctionBuilderTests {
 	public void filters() {
 		AtomicInteger filterCount = new AtomicInteger();
 
-		RouterFunction<?> route = RouterFunctions.builder()
-				.routeGet("/foo", request -> ServerResponse.ok().build())
-				.routeGet("/bar", request -> Mono.error(new IllegalStateException()))
-				.filterBefore(request -> {
+		RouterFunction<?> route = RouterFunctions.route()
+				.GET("/foo", request -> ServerResponse.ok().build())
+				.GET("/bar", request -> Mono.error(new IllegalStateException()))
+				.before(request -> {
 					int count = filterCount.getAndIncrement();
 					assertEquals(0, count);
-					return Mono.just(request);
+					return request;
 				})
-				.filterAfter((request, response) -> {
+				.after((request, response) -> {
 					int count = filterCount.getAndIncrement();
 					assertEquals(3, count);
-					return Mono.just(response);
+					return response;
 				})
 				.filter((request, next) -> {
 					int count = filterCount.getAndIncrement();
@@ -120,7 +175,7 @@ public class RouterFunctionBuilderTests {
 					assertEquals(2, count);
 					return responseMono;
 				})
-				.filterException(IllegalStateException.class, (e, request) -> ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).build())
+				.onError(IllegalStateException.class, (e, request) -> ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).build())
 				.build();
 
 		MockServerRequest fooRequest = MockServerRequest.builder().