GenericMessage unnecessarily copies message headers before passing to MessageHeaders [SPR-11268]

[spring-projects-issues]

Luke Jackson opened SPR-11268 and commented

In the following GenericMessage constructor:

public GenericMessage(T payload, Map<String, Object> headers) {
     Assert.notNull(payload, "payload must not be null");
     if (headers == null) {
          headers = new HashMap<String, Object>();
     }
     else {
          headers = new HashMap<String, Object>(headers);
     }
     this.headers = new MessageHeaders(headers);
     this.payload = payload;
}

The headers are being copied (presumably to ensure immutability).

However MessageHeaders itself copies the header map provided to it, which results in an unnecessary double copying of the headers map:

	public MessageHeaders(Map<String, Object> headers) {
		this.headers = (headers != null) ? new HashMap<String, Object>(headers) : new HashMap<String, Object>();
		IdGenerator generatorToUse = (idGenerator != null) ? idGenerator : defaultIdGenerator;
		this.headers.put(ID, generatorToUse.generateId());

		this.headers.put(TIMESTAMP, new Long(System.currentTimeMillis()));
	}

---

Affects: 4.0 GA

Referenced from: commits 3b14e97

[spring-projects-issues]

Artem Bilan commented

Don't see reason to do it for 3.0.1, but from other side GenericMessage class was moved to Spring Messaging module under Spring Framework project.
So, I move this issue to there.