feat: handle empty header value

springwolf-core/src/main/java/io/github/springwolf/core/asyncapi/annotations/AsyncOperation.java

@@ -62,7 +62,7 @@
 
             String description() default "";
 
-            String[] value() default "";
+            String[] value() default {};
 
             /**
              * The schema type of the header value according to AsyncAPI specification.

springwolf-core/src/main/java/io/github/springwolf/core/asyncapi/scanners/common/annotation/AsyncAnnotationUtil.java

@@ -98,7 +98,6 @@ private static List<String> getHeaderValues(
             List<AsyncOperation.Headers.Header> value, StringValueResolver stringValueResolver) {
         return value.stream()
                 .flatMap(it -> Arrays.stream(it.value()))
-                .filter(StringUtils::hasText)
                 .flatMap(text -> Optional.ofNullable(stringValueResolver.resolveStringValue(text)).stream())
                 .sorted()
                 .toList();

springwolf-core/src/test/java/io/github/springwolf/core/asyncapi/scanners/common/annotation/AsyncAnnotationUtilTest.java

@@ -133,6 +133,21 @@ void getAsyncHeadersWithoutValue() throws Exception {
         assertThat(headerProperty.getExamples()).isNull();
     }
 
+    @Test
+    void getAsyncHeadersWithEmptyValue() throws Exception {
+        // given
+        Method m = ClassWithHeaders.class.getDeclaredMethod("withEmptyValue", String.class);
+        AsyncOperation operation = m.getAnnotation(AsyncListener.class).operation();
+
+        // when
+        SchemaObject headers = AsyncAnnotationUtil.getAsyncHeaders(operation, stringValueResolver);
+
+        // then
+        SchemaObject headerProperty = (SchemaObject) headers.getProperties().get("headerResolved");
+        assertThat(headerProperty.getEnumValues()).containsExactly("Resolved");
+        assertThat(headerProperty.getExamples()).containsExactly("Resolved");
+    }
+
     @Test
     void getAsyncHeadersWithFormat() throws Exception {
         // given
@@ -494,6 +509,19 @@ private void withMergedValue(String payload) {}
                                                 values = {@AsyncOperation.Headers.Header(name = "header")})))
         private void withoutValue(String payload) {}
 
+        @AsyncListener(
+                operation =
+                        @AsyncOperation(
+                                channelName = "${test.property.test-channel}",
+                                headers =
+                                        @AsyncOperation.Headers(
+                                                values = {
+                                                    @AsyncOperation.Headers.Header(
+                                                            name = "header",
+                                                            value = {""})
+                                                })))
+        private void withEmptyValue(String payload) {}
+
         @AsyncListener(
                 operation =
                         @AsyncOperation(