@Test
public void copyHeadersNullMap() {
MessageHeaderAccessor headers = new MessageHeaderAccessor();
headers.copyHeaders(null);
headers.copyHeadersIfAbsent(null);
assertEquals(0, headers.toMap().size());
}
/**
* Return a mutable {@code MessageHeaderAccessor} for the given message attempting to match the
* type of accessor used to create the message headers, or otherwise wrapping the message with a
* {@code MessageHeaderAccessor} instance.
*
* <p>This is for cases where a header needs to be updated in generic code while preserving the
* accessor type for downstream processing.
*
* @return an accessor of the required type (never {@code null})
* @since 4.1
*/
public static MessageHeaderAccessor getMutableAccessor(Message<?> message) {
if (message.getHeaders() instanceof MutableMessageHeaders) {
MutableMessageHeaders mutableHeaders = (MutableMessageHeaders) message.getHeaders();
MessageHeaderAccessor accessor = mutableHeaders.getMessageHeaderAccessor();
if (accessor != null) {
return (accessor.isMutable() ? accessor : accessor.createAccessor(message));
}
}
return new MessageHeaderAccessor(message);
}
/**
* A variation of {@link #getAccessor(org.springframework.messaging.Message, Class)} with a {@code
* MessageHeaders} instance instead of a {@code Message}.
*
* <p>This is for cases when a full message may not have been created yet.
*
* @return an accessor instance of the specified type, or {@code null} if none
* @since 4.1
*/
@SuppressWarnings("unchecked")
public static <T extends MessageHeaderAccessor> T getAccessor(
MessageHeaders messageHeaders, Class<T> requiredType) {
if (messageHeaders instanceof MutableMessageHeaders) {
MutableMessageHeaders mutableHeaders = (MutableMessageHeaders) messageHeaders;
MessageHeaderAccessor headerAccessor = mutableHeaders.getMessageHeaderAccessor();
if (requiredType.isAssignableFrom(headerAccessor.getClass())) {
return (T) headerAccessor;
}
}
return null;
}
@Test
public void wrapMessage() {
Map<String, Object> original = new HashMap<>();
original.put("foo", "bar");
original.put("bar", "baz");
GenericMessage<String> message = new GenericMessage<>("p", original);
MessageHeaderAccessor headers = new MessageHeaderAccessor(message);
Map<String, Object> actual = headers.toMap();
assertEquals(4, actual.size());
assertNotNull(actual.get(MessageHeaders.ID));
assertNotNull(actual.get(MessageHeaders.TIMESTAMP));
assertEquals("bar", actual.get("foo"));
assertEquals("baz", actual.get("bar"));
}
public WebSocketMessage<?> encode(
Message<byte[]> message, Class<? extends WebSocketSession> sessionType) {
StompHeaderAccessor accessor =
MessageHeaderAccessor.getAccessor(message, StompHeaderAccessor.class);
Assert.notNull(accessor, "No StompHeaderAccessor available");
byte[] payload = message.getPayload();
byte[] bytes = ENCODER.encode(accessor.getMessageHeaders(), payload);
boolean useBinary =
(payload.length > 0
&& !(SockJsSession.class.isAssignableFrom(sessionType))
&& MimeTypeUtils.APPLICATION_OCTET_STREAM.isCompatibleWith(
accessor.getContentType()));
return (useBinary ? new BinaryMessage(bytes) : new TextMessage(bytes));
}
@Test
public void empty() {
MessageHeaderAccessor headers = new MessageHeaderAccessor();
assertEquals(Collections.emptyMap(), headers.toMap());
}