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.

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/RepositoryRestHandlerMapping.java

@@ -15,6 +15,9 @@
  */
 package org.springframework.data.rest.webmvc;
 
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
@@ -66,7 +69,7 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 	private final RepositoryRestConfiguration configuration;
 	private final Repositories repositories;
 
-	private StringValueResolver embeddedValueResolver;
+	private RepositoryCorsConfigurationAccessor corsConfigurationAccessor;
 	private JpaHelper jpaHelper;
 
 	/**
@@ -99,6 +102,8 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 		this.mappings = mappings;
 		this.configuration = config;
 		this.repositories = repositories;
+		this.corsConfigurationAccessor = new RepositoryCorsConfigurationAccessor(mappings, repositories,
+				NoOpStringValueResolver.INSTANCE);
 	}
 
 	/**
@@ -108,14 +113,17 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 		this.jpaHelper = jpaHelper;
 	}
 
-	/* (non-Javadoc)
+	/*
+	 * (non-Javadoc)
 	 * @see org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#setEmbeddedValueResolver(org.springframework.util.StringValueResolver)
 	 */
 	@Override
 	public void setEmbeddedValueResolver(StringValueResolver resolver) {
 
-		embeddedValueResolver = resolver;
 		super.setEmbeddedValueResolver(resolver);
+
+		this.corsConfigurationAccessor = new RepositoryCorsConfigurationAccessor(mappings, repositories,
+				resolver == null ? NoOpStringValueResolver.INSTANCE : resolver);
 	}
 
 	/*
@@ -207,15 +215,10 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 			return corsConfiguration;
 		}
 
-		// Repository root resource
-		CorsConfiguration repositoryConfiguration = new CorsConfigurationAccessor(mappings, repositories,
-				embeddedValueResolver).findCorsConfiguration(lookupPath);
+		CorsConfiguration repositoryCorsConfiguration = corsConfigurationAccessor.findCorsConfiguration(lookupPath);
 
-		if (repositoryConfiguration != null) {
-			return corsConfiguration != null ? corsConfiguration.combine(repositoryConfiguration) : repositoryConfiguration;
-		}
-
-		return corsConfiguration;
+		return corsConfiguration == null ? repositoryCorsConfiguration
+				: corsConfiguration.combine(repositoryCorsConfiguration);
 	}
 
 	/**
@@ -231,37 +234,40 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 	}
 
 	/**
-	 * Accessor to obtain {@link CorsConfiguration} for exposed repositories.
-	 * <p>
-	 * Exported Repository classes can be annotated with {@link CrossOrigin} to configure CORS for a specific repository.
+	 * No-op {@link StringValueResolver} that returns the given {@link String} value as is.
 	 *
-	 * @author Mark Paluch
+	 * @author Oliver Gierke
 	 * @since 2.6
 	 */
-	static class CorsConfigurationAccessor {
+	enum NoOpStringValueResolver implements StringValueResolver {
 
-		private final ResourceMappings mappings;
-		private final Repositories repositories;
-		private final StringValueResolver embeddedValueResolver;
+		INSTANCE;
 
-		/**
-		 * Creates a new {@link CorsConfigurationAccessor} given {@link ResourceMappings}, {@link Repositories} and
-		 * {@link StringValueResolver}.
-		 *
-		 * @param mappings must not be {@literal null}.
-		 * @param repositories must not be {@literal null}.
-		 * @param embeddedValueResolver may be {@literal null} if not present.
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.util.StringValueResolver#resolveStringValue(java.lang.String)
 		 */
-		CorsConfigurationAccessor(ResourceMappings mappings, Repositories repositories,
-				StringValueResolver embeddedValueResolver) {
-
-			Assert.notNull(mappings, "ResourceMappings must not be null!");
-			Assert.notNull(repositories, "Repositories must not be null!");
-
-			this.mappings = mappings;
-			this.repositories = repositories;
-			this.embeddedValueResolver = embeddedValueResolver;
+		@Override
+		public String resolveStringValue(String value) {
+			return value;
 		}
+	}
+
+	/**
+	 * Accessor to obtain {@link CorsConfiguration} for exposed repositories.
+	 * <p>
+	 * Exported repository classes can be annotated with {@link CrossOrigin} to configure CORS for a specific repository.
+	 *
+	 * @author Mark Paluch
+	 * @author Oliver Gierke
+	 * @since 2.6
+	 */
+	@RequiredArgsConstructor
+	static class RepositoryCorsConfigurationAccessor {
+
+		private final @NonNull ResourceMappings mappings;
+		private final @NonNull Repositories repositories;
+		private final @NonNull StringValueResolver embeddedValueResolver;
 
 		CorsConfiguration findCorsConfiguration(String lookupPath) {
 
@@ -305,7 +311,7 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 			if (CollectionUtils.isEmpty(config.getAllowedOrigins())) {
 				config.setAllowedOrigins(Arrays.asList(CrossOrigin.DEFAULT_ORIGINS));
 			}
-			
+
 			if (CollectionUtils.isEmpty(config.getAllowedMethods())) {
 				for (HttpMethod httpMethod : HttpMethod.values()) {
 					config.addAllowedMethod(httpMethod);
@@ -362,7 +368,7 @@ public class RepositoryRestHandlerMapping extends BasePathAwareHandlerMapping {
 		}
 
 		private String resolveCorsAnnotationValue(String value) {
-			return (this.embeddedValueResolver != null ? this.embeddedValueResolver.resolveStringValue(value) : value);
+			return this.embeddedValueResolver.resolveStringValue(value);
 		}
 	}
 }

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/RepositoryCorsConfigurationAccessorUnitTests.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.data.rest.webmvc;
 
-import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.MatcherAssert.*;
 import static org.hamcrest.Matchers.*;
 
 import org.junit.Before;
@@ -25,28 +25,31 @@ import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 import org.springframework.data.repository.support.Repositories;
 import org.springframework.data.rest.core.mapping.ResourceMappings;
-import org.springframework.data.rest.webmvc.RepositoryRestHandlerMapping.CorsConfigurationAccessor;
+import org.springframework.data.rest.webmvc.RepositoryRestHandlerMapping.NoOpStringValueResolver;
+import org.springframework.data.rest.webmvc.RepositoryRestHandlerMapping.RepositoryCorsConfigurationAccessor;
 import org.springframework.web.bind.annotation.CrossOrigin;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.cors.CorsConfiguration;
 
 /**
- * Unit tests for {@link CorsConfigurationAccessor}.
+ * Unit tests for {@link RepositoryCorsConfigurationAccessor}.
  * 
  * @author Mark Paluch
+ * @author Oliver Gierke
  * @soundtrack Aso Mamiko - Drive Me Crazy (Club Mix)
+ * @since 2.6
  */
 @RunWith(MockitoJUnitRunner.class)
-public class CorsConfigurationAccessorUnitTests {
+public class RepositoryCorsConfigurationAccessorUnitTests {
 
-	CorsConfigurationAccessor accessor;
+	RepositoryCorsConfigurationAccessor accessor;
 
 	@Mock ResourceMappings mappings;
 	@Mock Repositories repositories;
 
 	@Before
 	public void before() throws Exception {
-		accessor = new CorsConfigurationAccessor(mappings, repositories, null);
+		accessor = new RepositoryCorsConfigurationAccessor(mappings, repositories, NoOpStringValueResolver.INSTANCE);
 	}
 
 	/**
@@ -90,7 +93,10 @@ public class CorsConfigurationAccessorUnitTests {
 	@CrossOrigin
 	interface AnnotatedRepository {}
 
-	@CrossOrigin(origins = "http://far.far.away", allowedHeaders = "Content-type", maxAge = 1234,
-			exposedHeaders = "Accept", methods = RequestMethod.PATCH, allowCredentials = "true")
+	@CrossOrigin(origins = "http://far.far.away", //
+			allowedHeaders = "Content-type", //
+			maxAge = 1234, exposedHeaders = "Accept", //
+			methods = RequestMethod.PATCH, //
+			allowCredentials = "true")
 	interface FullyConfiguredCorsRepository {}
 }

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/RepositoryRestHandlerMappingUnitTests.java

@@ -27,6 +27,7 @@ import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.repository.support.Repositories;
 import org.springframework.data.rest.core.config.EnumTranslationConfiguration;
 import org.springframework.data.rest.core.config.MetadataConfiguration;
 import org.springframework.data.rest.core.config.ProjectionDefinitionConfiguration;
@@ -57,6 +58,7 @@ public class RepositoryRestHandlerMappingUnitTests {
 	}
 
 	@Mock ResourceMappings mappings;
+	@Mock Repositories repositories;
 
 	RepositoryRestConfiguration configuration;
 	RepositoryRestHandlerMapping handlerMapping;
@@ -69,7 +71,7 @@ public class RepositoryRestHandlerMappingUnitTests {
 		configuration = new RepositoryRestConfiguration(new ProjectionDefinitionConfiguration(),
 				new MetadataConfiguration(), mock(EnumTranslationConfiguration.class));
 
-		handlerMapping = new RepositoryRestHandlerMapping(mappings, configuration);
+		handlerMapping = new RepositoryRestHandlerMapping(mappings, configuration, repositories);
 		handlerMapping.setApplicationContext(CONTEXT);
 
 		mockRequest = new MockHttpServletRequest();