Convert Class header values using getName()

Author: garyrussell

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/support/DefaultMessagePropertiesConverter.java

@@ -184,7 +184,7 @@ private Map<String, Object> convertHeadersIfNecessary(Map<String, Object> header
 	private Object convertHeaderValueIfNecessary(@Nullable Object valueArg) {
 		Object value = valueArg;
 		boolean valid = (value instanceof String) || (value instanceof byte[]) // NOSONAR boolean complexity
-				|| (value instanceof Boolean)
+				|| (value instanceof Boolean) || (value instanceof Class)
 				|| (value instanceof LongString) || (value instanceof Integer) || (value instanceof Long)
 				|| (value instanceof Float) || (value instanceof Double) || (value instanceof BigDecimal)
 				|| (value instanceof Short) || (value instanceof Byte) || (value instanceof Date)
@@ -216,6 +216,9 @@ else if (value instanceof Map<?, ?>) {
 			}
 			value = writableMap;
 		}
+		else if (value instanceof Class) {
+			value = ((Class<?>) value).getName();
+		}
 		return value;
 	}
 

spring-rabbit/src/test/java/org/springframework/amqp/rabbit/support/DefaultMessagePropertiesConverterTests.java

@@ -193,6 +193,14 @@ public void testInboundDeliveryMode() {
 		assertThat(props.getDeliveryMode()).isNull();
 	}
 
+	@Test
+	public void testClassHeader() {
+		MessageProperties props = new MessageProperties();
+		props.setHeader("aClass", getClass());
+		BasicProperties basic = new DefaultMessagePropertiesConverter().fromMessageProperties(props, "UTF8");
+		assertThat(basic.getHeaders().get("aClass")).isEqualTo(getClass().getName());
+	}
+
 	private static class Foo {
 
 		Foo() {

src/reference/asciidoc/amqp.adoc

@@ -3655,6 +3655,9 @@ Also, the inbound `userId` property is no longer mapped to `MessageProperties.us
 It is mapped to `MessageProperties.receivedUserId` instead.
 These changes are to avoid unexpected propagation of these properties if the same `MessageProperties` object is used for an outbound message.
 
+Starting with version 2.2, the `DefaultMessagePropertiesConverter` converts any custom headers with values of type `Class<?>`  using `getName()` instead of `toString()`; this avoids consuming application having to parse the class name out of the `toString()` representation.
+For rolling upgrades, you may need to change your consumers to understand both formats until all producers are upgraded.
+
 [[post-processing]]
 ==== Modifying Messages - Compression and More
 

src/reference/asciidoc/whats-new.adoc

@@ -60,3 +60,6 @@ See <<cluster>> for more information.
 
 The `Declarables` object (for declaring multiple queues, exchanges, bindings) now has a filtered getter for each type.
 See <<collection-declaration>> for more information.
+
+Outbound headers with values of type `Class<?>` are now mapped using `getName()` instead of `toString()`.
+See <<message-properties-converters>> for more information.