GH-3083: Support @Header with dotted literals

Fixes #3083

`@Header("foo.bar")` means extract property `bar` from header `foo`.

Support `@Header("'foo.bar'")`, meaning get the value of header `foo.bar`.

**cherry-pick to 5.1.x, 4.3.x**

# Conflicts:
#	spring-integration-core/src/test/java/org/springframework/integration/handler/MethodInvokingMessageProcessorTests.java

Author: garyrussell

spring-integration-core/src/main/java/org/springframework/integration/handler/support/MessagingMethodInvokerHelper.java

@@ -1267,9 +1267,13 @@ private String determineHeaderExpression(Annotation headerAnnotation, MethodPara
 			AnnotationAttributes annotationAttributes =
 					(AnnotationAttributes) AnnotationUtils.getAnnotationAttributes(headerAnnotation);
 			String valueAttribute = annotationAttributes.getString(AnnotationUtils.VALUE);
+			int len = valueAttribute == null ? 0 : valueAttribute.length();
 			if (!StringUtils.hasText(valueAttribute)) {
 				headerName = methodParameter.getParameterName();
 			}
+			else if (len > 2 && valueAttribute.charAt(0) == '\'' && valueAttribute.charAt(len - 1) == '\'') {
+				headerName = valueAttribute.substring(1, len - 1);
+			}
 			else if (valueAttribute.indexOf('.') != -1) {
 				String[] tokens = valueAttribute.split("\\.", 2);
 				headerName = tokens[0];

spring-integration-core/src/test/java/org/springframework/integration/handler/MethodInvokingMessageProcessorTests.java

@@ -170,6 +170,7 @@ public Person(String fname, String lname) {
 				this.name = fname + " " + lname;
 			}
 
+			@Override
 			public String toString() {
 				return "Person: " + this.name;
 			}
@@ -552,7 +553,8 @@ private void optionalAndRequiredWithAnnotatedMethodGuts(MethodInvokingMessagePro
 	@Test
 	public void optionalAndRequiredDottedWithAnnotatedMethod() throws Exception {
 		AnnotatedTestService service = new AnnotatedTestService();
-		Method method = service.getClass().getMethod("optionalAndRequiredDottedHeader", String.class, Integer.class);
+		Method method = service.getClass().getMethod("optionalAndRequiredDottedHeader", String.class, Integer.class,
+				String.class);
 		MethodInvokingMessageProcessor processor = new MethodInvokingMessageProcessor(service, method);
 		processor.setUseSpelInvoker(true);
 		optionalAndRequiredDottedWithAnnotatedMethodGuts(processor, false);
@@ -561,7 +563,8 @@ public void optionalAndRequiredDottedWithAnnotatedMethod() throws Exception {
 	@Test
 	public void compiledOptionalAndRequiredDottedWithAnnotatedMethod() throws Exception {
 		AnnotatedTestService service = new AnnotatedTestService();
-		Method method = service.getClass().getMethod("optionalAndRequiredDottedHeader", String.class, Integer.class);
+		Method method = service.getClass().getMethod("optionalAndRequiredDottedHeader", String.class, Integer.class,
+				String.class);
 		MethodInvokingMessageProcessor processor = new MethodInvokingMessageProcessor(service, method);
 		processor.setUseSpelInvoker(true);
 		DirectFieldAccessor compilerConfigAccessor = compileImmediate(processor);
@@ -577,17 +580,20 @@ private void optionalAndRequiredDottedWithAnnotatedMethodGuts(MethodInvokingMess
 		processor.setBeanFactory(mock(BeanFactory.class));
 		Message<String> message = MessageBuilder.withPayload("hello")
 				.setHeader("dot2", new DotBean())
+				.setHeader("dotted.literal", "dotted")
 				.build();
 		Object result = processor.processMessage(message);
-		assertEquals("null42", result);
+		assertEquals("null42dotted", result);
 		message = MessageBuilder.withPayload("hello")
 				.setHeader("dot1", new DotBean())
 				.setHeader("dot2", new DotBean())
+				.setHeader("dotted.literal", "dotted")
 				.build();
 		result = processor.processMessage(message);
-		assertEquals("bar42", result);
+		assertEquals("bar42dotted", result);
 		message = MessageBuilder.withPayload("hello")
 				.setHeader("dot1", new DotBean())
+				.setHeader("dotted.literal", "dotted")
 				.build();
 		try {
 			result = processor.processMessage(message);
@@ -1380,8 +1386,8 @@ public String optionalAndRequiredHeader(@Header(required = false) String prop,
 		}
 
 		public String optionalAndRequiredDottedHeader(@Header(name = "dot1.foo", required = false) String prop,
-				@Header(name = "dot2.baz") Integer num) {
-			return prop + num;
+				@Header(name = "dot2.baz") Integer num, @Header("'dotted.literal'") String dotted) {
+			return prop + num + dotted;
 		}
 
 		public Properties propertiesMethod(Properties properties) {