Enhance ParameterizableViewController

This change two new capabilities to ParameterizableViewController:

 - configure a View instance (in addition to view name)
 - configure response status code

The status code may be useful to send a 404 while also writing to the
body using a view.

The status code may also be used to override the redirect status code
of RedirectView. Even today it's possible to configure a "redirect:"
prefixed view name but the status code could not be selected. When a
3xx status is set, the code is passed on to the RedirectView while the
view name is automatically prefixed with "redirect:" (if not already).

For full control over RedirectView it is now also possible to
parameterize the controller with a View instance.

As one more possible resulting variation, given status 204 and no view
the request is considered handled (controller returns null).

This change is preparation for SPR-11543.

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/support/ParameterizableViewControllerTests.java

@@ -0,0 +1,126 @@
+/*
+ * Copyright 2002-2014 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.web.servlet.mvc.support;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.http.HttpStatus;
+import org.springframework.mock.web.test.MockHttpServletRequest;
+import org.springframework.mock.web.test.MockHttpServletResponse;
+import org.springframework.web.servlet.ModelAndView;
+import org.springframework.web.servlet.View;
+import org.springframework.web.servlet.mvc.ParameterizableViewController;
+import org.springframework.web.servlet.view.RedirectView;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+
+/**
+ * Unit tests for
+ * {@link org.springframework.web.servlet.mvc.ParameterizableViewController}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.1
+ */
+public class ParameterizableViewControllerTests {
+
+	private ParameterizableViewController controller;
+
+	private MockHttpServletRequest request;
+
+	private MockHttpServletResponse response;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.controller = new ParameterizableViewController();
+		this.request = new MockHttpServletRequest("GET", "/");
+		this.response = new MockHttpServletResponse();
+	}
+
+
+	@Test
+	public void defaultViewName() throws Exception {
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+		assertNull(modelAndView.getViewName());
+	}
+
+	@Test
+	public void viewName() throws Exception {
+		this.controller.setViewName("view");
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+		assertEquals("view", modelAndView.getViewName());
+	}
+
+	@Test
+	public void viewNameAndStatus() throws Exception {
+		this.controller.setViewName("view");
+		this.controller.setStatusCode(HttpStatus.NOT_FOUND);
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+		assertEquals("view", modelAndView.getViewName());
+		assertEquals(404, this.response.getStatus());
+	}
+
+	@Test
+	public void viewNameAndStatus204() throws Exception {
+		this.controller.setStatusCode(HttpStatus.NO_CONTENT);
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+		assertNull(modelAndView);
+		assertEquals(204, this.response.getStatus());
+	}
+
+	@Test
+	public void redirectStatus() throws Exception {
+		this.controller.setStatusCode(HttpStatus.PERMANENT_REDIRECT);
+		this.controller.setViewName("/foo");
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+
+		assertEquals("redirect:/foo", modelAndView.getViewName());
+		assertEquals("3xx status should be left to RedirectView to set", 200, this.response.getStatus());
+		assertEquals(HttpStatus.PERMANENT_REDIRECT, this.request.getAttribute(View.RESPONSE_STATUS_ATTRIBUTE));
+	}
+
+	@Test
+	public void redirectStatusWithRedirectPrefix() throws Exception {
+		this.controller.setStatusCode(HttpStatus.PERMANENT_REDIRECT);
+		this.controller.setViewName("redirect:/foo");
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+
+		assertEquals("redirect:/foo", modelAndView.getViewName());
+		assertEquals("3xx status should be left to RedirectView to set", 200, this.response.getStatus());
+		assertEquals(HttpStatus.PERMANENT_REDIRECT, this.request.getAttribute(View.RESPONSE_STATUS_ATTRIBUTE));
+	}
+
+	@Test
+	public void redirectView() throws Exception {
+		RedirectView view = new RedirectView("/foo");
+		this.controller.setView(view);
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+		assertSame(view, modelAndView.getView());
+	}
+
+	@Test
+	public void statusOnly() throws Exception {
+		this.controller.setStatusCode(HttpStatus.NOT_FOUND);
+		this.controller.setStatusOnly(true);
+		ModelAndView modelAndView = this.controller.handleRequest(this.request, this.response);
+		assertNull(modelAndView);
+		assertEquals(404, this.response.getStatus());
+	}
+
+}