#1831 - Reset dummy invocation cache on request completion.

src/main/java/org/springframework/hateoas/config/WebMvcHateoasConfiguration.java

@@ -19,6 +19,9 @@ import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.config.BeanPostProcessor;
@@ -26,6 +29,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.hateoas.server.RepresentationModelProcessor;
+import org.springframework.hateoas.server.core.DummyInvocationUtils;
 import org.springframework.hateoas.server.mvc.RepresentationModelProcessorHandlerMethodReturnValueHandler;
 import org.springframework.hateoas.server.mvc.RepresentationModelProcessorInvoker;
 import org.springframework.hateoas.server.mvc.UriComponentsContributor;
@@ -33,6 +37,8 @@ import org.springframework.hateoas.server.mvc.WebMvcLinkBuilderFactory;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.lang.NonNull;
 import org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite;
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 
@@ -93,6 +99,15 @@ class WebMvcHateoasConfiguration {
 		public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
 			hypermediaConverters.augmentServer(converters);
 		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.web.servlet.config.annotation.WebMvcConfigurer#addInterceptors(org.springframework.web.servlet.config.annotation.InterceptorRegistry)
+		 */
+		@Override
+		public void addInterceptors(InterceptorRegistry registry) {
+			registry.addInterceptor(DummyInvocationUtilsCacheClearer.INSTANCE);
+		}
 	}
 
 	/**
@@ -132,4 +147,25 @@ class WebMvcHateoasConfiguration {
 			return bean;
 		}
 	}
+
+	/**
+	 * {@link HandlerInterceptor} to clear the cache in {@link DummyInvocationUtils}.
+	 *
+	 * @author Oliver Drotbohm
+	 */
+	enum DummyInvocationUtilsCacheClearer implements HandlerInterceptor {
+
+		INSTANCE;
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.web.servlet.HandlerInterceptor#afterCompletion(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Object, java.lang.Exception)
+		 */
+		@Override
+		public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
+				throws Exception {
+
+			DummyInvocationUtils.resetCache();
+		}
+	}
 }

src/main/java/org/springframework/hateoas/server/core/DummyInvocationUtils.java

@@ -180,6 +180,10 @@ public class DummyInvocationUtils {
 		return new DefaultMethodInvocation(type, method, parameters);
 	}
 
+	public static void resetCache() {
+		CACHE.remove();
+	}
+
 	@SuppressWarnings("unchecked")
 	private static <T> T getProxyWithInterceptor(Class<?> type, InvocationRecordingMethodInterceptor interceptor,
 			ClassLoader classLoader) {

src/test/java/org/springframework/hateoas/config/HypermediaWebMvcConfigurerTest.java

@@ -42,6 +42,7 @@ import org.springframework.hateoas.mediatype.hal.Jackson2HalModule;
 import org.springframework.hateoas.mediatype.hal.forms.Jackson2HalFormsModule;
 import org.springframework.hateoas.mediatype.uber.Jackson2UberModule;
 import org.springframework.hateoas.server.SimpleRepresentationModelAssembler;
+import org.springframework.hateoas.server.core.DummyInvocationUtils;
 import org.springframework.hateoas.support.Employee;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
@@ -51,7 +52,9 @@ import org.springframework.http.ResponseEntity;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.stereotype.Controller;
 import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.util.ConcurrentLruCache;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
@@ -263,6 +266,20 @@ class HypermediaWebMvcConfigurerTest {
 				.andExpect(status().isIAmATeapot());
 	}
 
+	@Test // #1831
+	void wipesDummyInvocationsCachePerRequest() throws Exception {
+
+		setUp(HalWebMvcConfig.class);
+
+		this.mockMvc.perform(get("/dynamicLink"))
+				.andExpect(status().isOk());
+
+		ThreadLocal<ConcurrentLruCache<?, ?>> cache = (ThreadLocal<ConcurrentLruCache<?, ?>>) ReflectionTestUtils.getField(
+				null, DummyInvocationUtils.class, "CACHE");
+
+		assertThat(cache.get().size()).isZero();
+	}
+
 	private void verifyRootUriServesHypermedia(MediaType mediaType) throws Exception {
 		verifyRootUriServesHypermedia(mediaType, mediaType);
 	}
@@ -468,6 +485,12 @@ class HypermediaWebMvcConfigurerTest {
 
 			return this.assembler.toModel(newEmployee);
 		}
+
+		@GetMapping("/dynamicLink")
+		EntityModel<Employee> dynamicLink() {
+			return EntityModel.of(employees.get(0)) //
+					.add(linkTo(methodOn(TestController.class).employee("1")).withSelfRel());
+		}
 	}
 
 	static class EmployeeResourceAssembler implements SimpleRepresentationModelAssembler<Employee> {