DATAREST-573 - Polishing.

Removed RepositoryRestConfiguration.addCorsMapping(…) as we currently don't have any other shortcut methods for configuration like this.

Tweaked the setup of (now Repository)CorsConfigurationAccessor to be created earlier so that we avoid recreation for every lookup. Introduced a NoOpStringValueResolver to be used by default so that we don't need to deal with the case of the resolver being null at the end of the call chain. Replaced constructor of RepositoryCorsConfigurationAccessor with corresponding Lombok annotation.

Updated reference documentation accordingly.

Original pull request: #233.

src/main/asciidoc/configuring-cors.adoc

@@ -21,7 +21,8 @@ In the above example CORS support is enabled for the whole `PersonRepository`. `
 [source, java]
 ----
 @CrossOrigin(origins = "http://domain2.com",
-		methods = { RequestMethod.GET, RequestMethod.POST, RequestMethod.DELETE }, maxAge = 3600)
+  methods = { RequestMethod.GET, RequestMethod.POST, RequestMethod.DELETE },
+  maxAge = 3600)
 interface PersonRepository extends CrudRepository<Person, Long> {}
 ----
 
@@ -34,14 +35,13 @@ Spring Data REST fully supports http://docs.spring.io/spring/docs/current/spring
 [source, java]
 ----
 @RepositoryRestController
-@RequestMapping("/person")
 public class PersonController {
 
-	@CrossOrigin(maxAge = 3600)
-	@RequestMapping(method = RequestMethod.GET, "/xml/{id}", produces = MediaType.APPLICATION_XML_VALUE)
-	public Person retrieve(@PathVariable Long id) {
-		// ...
-	}
+  @CrossOrigin(maxAge = 3600)
+  @RequestMapping(path = "/people/xml/{id}", method = RequestMethod.GET, produces = MediaType.APPLICATION_XML_VALUE)
+  public Person retrieve(@PathVariable Long id) {
+    // …
+  }
 }
 ----
 
@@ -61,12 +61,12 @@ public class SpringDataRestCustomization extends RepositoryRestConfigurerAdapter
   @Override
   public void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
 
-    config.addCorsMapping("/person/**")
-        .allowedOrigins("http://domain2.com")
-        .allowedMethods("PUT", "DELETE")
-        .allowedHeaders("header1", "header2", "header3")
-        .exposedHeaders("header1", "header2")
-        .allowCredentials(false).maxAge(3600);
+    config.getCorsRegistry().addCorsMapping("/person/**")
+      .allowedOrigins("http://domain2.com")
+      .allowedMethods("PUT", "DELETE")
+      .allowedHeaders("header1", "header2", "header3")
+      .exposedHeaders("header1", "header2")
+      .allowCredentials(false).maxAge(3600);
   }
 }
 ----