Polish CORS global configuration

This commit introduces the following changes:
 - configureCors(CorsConfigurer configurer) is renamed to
   addCorsMappings(CorsRegistry registry)
 - enableCors(String... pathPatterns) is renamed to
   addMapping(String pathPattern)
 - <cors /> element must have at least one <mapping /> child
   element in order to be consistent with XML based configuration
   and have more explicit configuration

Issues: SPR-12933, SPR-13046

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/CorsRegistration.java

@@ -34,12 +34,12 @@ import org.springframework.web.cors.CorsConfiguration;
  */
 public class CorsRegistration {
 
-	private final String[] pathPatterns;
+	private final String pathPattern;
 
 	private final CorsConfiguration config;
 
-	public CorsRegistration(String... pathPatterns) {
-		this.pathPatterns = (pathPatterns.length == 0 ? new String[]{ "/**" } : pathPatterns);
+	public CorsRegistration(String pathPattern) {
+		this.pathPattern = pathPattern;
 		// Same default values than @CrossOrigin annotation + allows simple methods
 		this.config = new CorsConfiguration();
 		this.config.addAllowedOrigin("*");
@@ -81,8 +81,8 @@ public class CorsRegistration {
 		return this;
 	}
 
-	protected String[] getPathPatterns() {
-		return this.pathPatterns;
+	protected String getPathPattern() {
+		return this.pathPattern;
 	}
 
 	protected CorsConfiguration getCorsConfiguration() {

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/CorsRegistry.java

@@ -24,25 +24,27 @@ import java.util.Map;
 import org.springframework.web.cors.CorsConfiguration;
 
 /**
- * Assist with the registration of {@link CorsConfiguration} mapped to one or more path patterns.
+ * Assist with the registration of {@link CorsConfiguration} mapped on a path pattern.
  * @author Sebastien Deleuze
  *
  * @since 4.2
  * @see CorsRegistration
  */
-public class CorsConfigurer {
+public class CorsRegistry {
 
 	private final List<CorsRegistration> registrations = new ArrayList<CorsRegistration>();
 
 
 	/**
-	 * Enable cross origin requests on the specified path patterns. If no path pattern is specified,
-	 * cross-origin request handling is mapped on "/**" .
+	 * Enable cross origin requests processing on the specified path pattern.
+	 * Exact path mapping URIs (such as "/admin") are supported as well as Ant-stype path
+	 * patterns (such as /admin/**).
 	 *
-	 * <p>By default, all origins, all headers and credentials are allowed. Max age is set to 30 minutes.</p>
+	 * <p>By default, all origins, all headers, credentials and GET, HEAD, POST methods are allowed.
+	 * Max age is set to 30 minutes.</p>
 	 */
-	public CorsRegistration enableCors(String... pathPatterns) {
-		CorsRegistration registration = new CorsRegistration(pathPatterns);
+	public CorsRegistration addMapping(String pathPattern) {
+		CorsRegistration registration = new CorsRegistration(pathPattern);
 		this.registrations.add(registration);
 		return registration;
 	}
@@ -50,9 +52,7 @@ public class CorsConfigurer {
 	protected Map<String, CorsConfiguration> getCorsConfigurations() {
 		Map<String, CorsConfiguration> configs = new LinkedHashMap<String, CorsConfiguration>(this.registrations.size());
 		for (CorsRegistration registration : this.registrations) {
-			for (String pathPattern : registration.getPathPatterns()) {
-				configs.put(pathPattern, registration.getCorsConfiguration());
-			}
+			configs.put(registration.getPathPattern(), registration.getCorsConfiguration());
 		}
 		return configs;
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.java

@@ -133,8 +133,8 @@ public class DelegatingWebMvcConfiguration extends WebMvcConfigurationSupport {
 	}
 
 	@Override
-	protected void configureCors(CorsConfigurer configurer) {
-		this.configurers.configureCors(configurer);
+	protected void addCorsMappings(CorsRegistry registry) {
+		this.configurers.addCorsMappings(registry);
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupport.java

@@ -875,19 +875,19 @@ public class WebMvcConfigurationSupport implements ApplicationContextAware, Serv
 	 */
 	protected final Map<String, CorsConfiguration> getCorsConfigurations() {
 		if (this.corsConfigurations == null) {
-			CorsConfigurer registry = new CorsConfigurer();
-			configureCors(registry);
+			CorsRegistry registry = new CorsRegistry();
+			addCorsMappings(registry);
 			this.corsConfigurations = registry.getCorsConfigurations();
 		}
 		return this.corsConfigurations;
 	}
 
 	/**
-	 * Override this method to configure cross-origin requests handling.
+	 * Override this method to configure cross origin requests processing.
 	 * @since 4.2
-	 * @see CorsConfigurer
+	 * @see CorsRegistry
 	 */
-	protected void configureCors(CorsConfigurer configurer) {
+	protected void addCorsMappings(CorsRegistry registry) {
 	}
 
 

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurer.java

@@ -183,9 +183,9 @@ public interface WebMvcConfigurer {
 	void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer);
 
 	/**
-	 * Configure cross-origin requests handling.
+	 * Configure cross origin requests processing.
 	 * @since 4.2
 	 */
-	void configureCors(CorsConfigurer configurer);
+	void addCorsMappings(CorsRegistry registry);
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerAdapter.java

@@ -170,7 +170,7 @@ public abstract class WebMvcConfigurerAdapter implements WebMvcConfigurer {
 	 * <p>This implementation is empty.
 	 */
 	@Override
-	public void configureCors(CorsConfigurer configurer) {
+	public void addCorsMappings(CorsRegistry registry) {
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurerComposite.java

@@ -154,9 +154,9 @@ class WebMvcConfigurerComposite implements WebMvcConfigurer {
 	}
 
 	@Override
-	public void configureCors(CorsConfigurer configurer) {
+	public void addCorsMappings(CorsRegistry registry) {
 		for (WebMvcConfigurer delegate : this.delegates) {
-			delegate.configureCors(configurer);
+			delegate.addCorsMappings(registry);
 		}
 	}