IntegrationObjectSupport.conversionService property has flipped access modifiers

[chrylis]

In what version(s) of Spring Integration are you seeing this issue?

5.5.14

Describe the bug

In IntegrationObjectSupport, most of the properties have public setters (for external configuration) and protected getters. However, the conversionService property has this reversed: The setter is protected but the getter is public. I am wanting to externally set the conversionService on a channel adapter (specifically SNS, because I want to customize the JSON formatting but after the adapter has evaluated expressions against the payload POJO), but the property isn't visible unless I subclass it. Based on the other dependency properties, this appears to be a typo in the declarations.

[artembilan]

I don't think we need to worry about making getter as protected: having it as public does not hurt
But I definitely agree that setter has to become public.

Feel from to contribute the fix!

As a side effect: I'm not sure what you talk about JSON formatting and this ConversionService relationship.
Would you mind to share more info: I just don't understand how ConversionService helps in JSON formatting...
Thanks

[chrylis]

I wish to supply my own custom-configured Jackson converter for SNS operations. The only two ways I can see to do this are to provide a named bean and invoke it from the bodyExpression or to provide a ConversionService with a custom Jackson mapper.

[artembilan]

Hm. OK. You know it might be better to separate concerns and have a transformer upfront which would do that JSON serialization: https://docs.spring.io/spring-integration/docs/current/reference/html/message-transformation.html#json-transformers

[chrylis]

Hm. OK. You know it might be better to separate concerns and have a transformer upfront which would do that JSON serialization: https://docs.spring.io/spring-integration/docs/current/reference/html/message-transformation.html#json-transformers

That was my first attempt, but doing that results in a payload type of String by the time the SnsMessageHandler sees the message, so the structured properties are not available for setting as message attributes or (now) group and deduplication IDs. I'd have to duplicate the conversion to PublishRequest into every pipeline before sending it to SnsMessageHandler.

[artembilan]

I'm not sure why do you need to do that?
The logic there is like this:

			if (this.bodyExpression != null) {
				snsMessage = this.bodyExpression.getValue(getEvaluationContext(), message);
			}

			if (snsMessage instanceof SnsBodyBuilder) {
				publishRequest.withMessageStructure("json").setMessage(((SnsBodyBuilder) snsMessage).build());
			}
			else {
				publishRequest.setMessage(getConversionService().convert(snsMessage, String.class));
			}

So, if no bodyExpression, and payload is not an SnsBodyBuilder, we set the provided payload after converting to String, where string to string is indeed string.
What do I miss?