Explicitly specify SecurityContext type

This ensures that Mono.justOrEmpty knows the type is not an Optional.

webflux/src/main/java/org/springframework/security/web/server/context/ServerWebExchangeAttributeSecurityContextRepository.java

@@ -36,6 +36,6 @@ public class ServerWebExchangeAttributeSecurityContextRepository implements Secu
 	}
 
 	public Mono<SecurityContext> load(ServerWebExchange exchange) {
-		return Mono.justOrEmpty(exchange.getAttribute(ATTR));
+		return Mono.justOrEmpty(exchange.<SecurityContext>getAttribute(ATTR));
 	}
 }

webflux/src/test/java/org/springframework/security/web/server/context/ServerWebExchangeAttributeSecurityContextRepositoryTests.java

@@ -0,0 +1,48 @@
+/*
+ *
+ *  * Copyright 2002-2017 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.security.web.server.context;
+
+import org.junit.Test;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.security.core.context.SecurityContext;
+import org.springframework.security.core.context.SecurityContextImpl;
+import org.springframework.web.server.ServerWebExchange;
+import reactor.core.publisher.Mono;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Rob Winch
+ * @since 5.0
+ */
+public class ServerWebExchangeAttributeSecurityContextRepositoryTests {
+	ServerWebExchangeAttributeSecurityContextRepository repository = new ServerWebExchangeAttributeSecurityContextRepository();
+	ServerWebExchange exchange = MockServerHttpRequest.get("/").toExchange();
+
+	@Test
+	public void saveAndLoad() {
+		SecurityContext context = new SecurityContextImpl();
+		this.repository.save(this.exchange, context);
+
+		Mono<SecurityContext> loaded = this.repository.load(this.exchange);
+
+		assertThat(context).isSameAs(loaded.block());
+	}
+
+}