Resolve native header values with @Header

The @Header annotation in spring-messaging now resolves values from the
nested "nativeHeaders" map as well as top-level header map values.

In case of ambiguity (a value that exists in both), the top-level map
value is used and a warning message is printed. This is unlikly in most
cases but can be resolved by prefixing the header value with
"nativeHeadres.myHeader".

Issue: SPR-11326

spring-messaging/src/test/java/org/springframework/messaging/handler/annotation/support/HeaderMethodArgumentResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -30,6 +30,7 @@ import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHandlingException;
 import org.springframework.messaging.handler.annotation.Header;
 import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.messaging.support.NativeMessageHeaderAccessor;
 
 import static org.junit.Assert.*;
 
@@ -47,6 +48,7 @@ public class HeaderMethodArgumentResolverTests {
 	private MethodParameter paramNamedDefaultValueStringHeader;
 	private MethodParameter paramSystemProperty;
 	private MethodParameter paramNotAnnotated;
+	private MethodParameter paramNativeHeader;
 
 
 	@Before
@@ -57,11 +59,12 @@ public class HeaderMethodArgumentResolverTests {
 		this.resolver = new HeaderMethodArgumentResolver(new DefaultConversionService(), cxt.getBeanFactory());
 
 		Method method = getClass().getDeclaredMethod("handleMessage",
-				String.class, String.class, String.class, String.class);
+				String.class, String.class, String.class, String.class, String.class);
 		this.paramRequired = new MethodParameter(method, 0);
 		this.paramNamedDefaultValueStringHeader = new MethodParameter(method, 1);
 		this.paramSystemProperty = new MethodParameter(method, 2);
 		this.paramNotAnnotated = new MethodParameter(method, 3);
+		this.paramNativeHeader = new MethodParameter(method, 4);
 
 		this.paramRequired.initParameterNameDiscovery(new DefaultParameterNameDiscoverer());
 		GenericTypeResolver.resolveParameterType(this.paramRequired, HeaderMethodArgumentResolver.class);
@@ -76,7 +79,33 @@ public class HeaderMethodArgumentResolverTests {
 	@Test
 	public void resolveArgument() throws Exception {
 		Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).setHeader("param1", "foo").build();
-		this.resolver.resolveArgument(this.paramRequired, message);
+		Object result = this.resolver.resolveArgument(this.paramRequired, message);
+
+		assertEquals("foo", result);
+	}
+
+	// SPR-11326
+
+	@Test
+	public void resolveArgumentNativeHeader() throws Exception {
+
+		TestMessageHeaderAccessor headers = new TestMessageHeaderAccessor();
+		headers.setNativeHeader("param1", "foo");
+		Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).setHeaders(headers).build();
+
+		assertEquals("foo", this.resolver.resolveArgument(this.paramRequired, message));
+	}
+
+	@Test
+	public void resolveArgumentNativeHeaderAmbiguity() throws Exception {
+
+		TestMessageHeaderAccessor headers = new TestMessageHeaderAccessor();
+		headers.setHeader("param1", "foo");
+		headers.setNativeHeader("param1", "native-foo");
+		Message<byte[]> message = MessageBuilder.withPayload(new byte[0]).setHeaders(headers).build();
+
+		assertEquals("foo", this.resolver.resolveArgument(this.paramRequired, message));
+		assertEquals("native-foo", this.resolver.resolveArgument(this.paramNativeHeader, message));
 	}
 
 	@Test(expected = MessageHandlingException.class)
@@ -112,7 +141,16 @@ public class HeaderMethodArgumentResolverTests {
 			@Header String param1,
 			@Header(value = "name", defaultValue = "bar") String param2,
 			@Header(value = "name", defaultValue="#{systemProperties.systemProperty}") String param3,
-			String param4) {
+			String param4,
+			@Header("nativeHeaders.param1") String nativeHeaderParam1) {
+	}
+
+
+	public static class TestMessageHeaderAccessor extends NativeMessageHeaderAccessor {
+
+		protected TestMessageHeaderAccessor() {
+			super((Message<?>) null);
+		}
 	}
 
 }