GH-2908: Publisher: synthesize anns for @AliasFor

Fixes #2908

* make sure the attribute  is taken into account in @Header annotation

* remove useless spaces according to checkstyle rules

* make sure the expression attribute is taken into account as well in @payload annotation

Author: chengchen

spring-integration-core/src/main/java/org/springframework/integration/aop/MethodAnnotationPublisherMetadataSource.java

@@ -44,6 +44,7 @@
  * @author Artem Bilan
  * @author Gareth Chapman
  * @author Cameron Mayfield
+ * @author Chengchen Ji
  *
  * @since 2.0
  */
@@ -114,7 +115,7 @@ public Expression getExpressionForPayload(Method method) {
 								"@Payload can be used at most once on a @Publisher method, " +
 										"either at method-level or on a single parameter");
 
-						Assert.state("".equals(AnnotationUtils.getValue(currentAnnotation)),
+						Assert.state("".equals(AnnotationUtils.getValue(AnnotationUtils.synthesizeAnnotation(currentAnnotation, null))),
 								"@Payload on a parameter for a @Publisher method may not contain an expression");
 
 						payloadExpression =
@@ -204,8 +205,10 @@ private <T> T getAnnotationValue(Class<?> clazz, String attributeName, Class<T>
 	@SuppressWarnings("unchecked")
 	private <T> T getAnnotationValue(Annotation annotation, String attributeName, Class<T> expectedType) {
 		T value = null;
-		Object valueAsObject = (attributeName == null) ? AnnotationUtils.getValue(annotation)
-				: AnnotationUtils.getValue(annotation, attributeName);
+		Object valueAsObject = (attributeName == null) ?
+							AnnotationUtils.getValue(AnnotationUtils.synthesizeAnnotation(annotation, null)) :
+							AnnotationUtils.getValue(annotation, attributeName);
+
 		if (valueAsObject != null) {
 			if (expectedType.isAssignableFrom(valueAsObject.getClass())) {
 				value = (T) valueAsObject;

spring-integration-core/src/test/java/org/springframework/integration/aop/MethodAnnotationPublisherMetadataSourceTests.java

@@ -37,6 +37,7 @@
  * @author Mark Fisher
  * @author Artem Bilan
  * @author Cameron Mayfield
+ * @author Chengchen Ji
  *
  * @since 2.0
  */
@@ -116,6 +117,18 @@ public void voidReturnAndParameterPayloadAnnotation() {
 		assertThat(payloadExpression).isEqualTo("#args[0]");
 	}
 
+	@Test(expected = IllegalStateException.class)
+	public void voidReturnAndParameterPayloadAnnotationWithExpression() {
+		Method method = getMethod("methodWithVoidReturnAndParameterPayloadAnnotationWithExpression", String.class);
+		source.getExpressionForPayload(method).getExpressionString();
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void voidReturnAndParameterPayloadAnnotationWithValue() {
+		Method method = getMethod("methodWithVoidReturnAndParameterPayloadAnnotationWithValue", String.class);
+		source.getExpressionForPayload(method).getExpressionString();
+	}
+
 	@Test(expected = IllegalArgumentException.class)
 	public void voidReturnAndNoPayloadAnnotation() {
 		Method method = getMethod("methodWithVoidReturnAndNoPayloadAnnotation", String.class);
@@ -182,13 +195,21 @@ public void methodWithVoidReturnAndReturnValueAsPayload() {
 
 	@Publisher
 	@Payload("testExpression2")
-	public void methodWithHeaderAnnotations(String arg1, @Header("foo") String h1, @Header("bar") String h2) {
+	public void methodWithHeaderAnnotations(String arg1, @Header("foo") String h1, @Header(name = "bar") String h2) {
 	}
 
 	@Publisher
 	public void methodWithVoidReturnAndParameterPayloadAnnotation(@Payload String payload) {
 	}
 
+	@Publisher
+	public void methodWithVoidReturnAndParameterPayloadAnnotationWithExpression(@Payload(expression = "foo") String payload) {
+	}
+
+	@Publisher
+	public void methodWithVoidReturnAndParameterPayloadAnnotationWithValue(@Payload("foo") String payload) {
+	}
+
 	@Publisher
 	public void methodWithVoidReturnAndNoPayloadAnnotation(String payload) {
 	}