Hi
An update on my working on this issue.
I follow the principle outlined by James on the Pipeline restructure.
The prepare exchange for next step is reduced to this principle:
protected Exchange prepareExchange(Exchange exchange) {
// now lets set the input of the next exchange to the output of the
// previous message if it is not null
if (exchange.hasOut()) {
exchange.setIn(exchange.getOut());
exchange.setOut(null);
}
return exchange;
}
That fits well with the Pipes And Filters EIP: output is the next input.
So the Pipelines is becoming nice and slick now.
On Fri, Jul 10, 2009 at 7:05 AM, Claus Ibsen<[email protected]> wrote:
> Now that we have opened the box with IN OUT FAULT api changes I would
> like to point out issues related to OUT
>
> Given this code:
>
> Exchange out = template.send("direct:start", new Processor() {
> public void process(Exchange exchange) throws Exception {
> exchange.getIn().setBody("Hello World");
> exchange.setPattern(ExchangePattern.InOnly);
> }
> });
>
> And this route:
>
> from("direct:start").transform(constant("Bye World"));
>
> What would the expected output of Exchange be?
>
> The current code asserts this:
>
> assertEquals("Hello World", out.getIn().getBody());
> assertEquals("Bye World", out.getOut().getBody());
>
> That looks fair. The route transforms (= set an OUT body) and we
> preserve the original IN.
> But the exchange pattern was InOnly but we get data in OUT also? Camel
> does not adhere strictly to the patterns.
>
>
> Now what if the route only changes the IN message (setBody only changes IN)
>
> from("direct:start").setBody(constant("Bye World"));
>
> What should the expected outcome be?
>
> Should it be as before?
>
> assertEquals("Hello World", out.getIn().getBody());
> assertEquals("Bye World", out.getOut().getBody());
>
> Or as this:
>
> assertEquals("Bye World", out.getIn().getBody());
> assertEquals(null, out.getOut().getBody());
>
>
> Its actually now that easy to get a closure on this one. Either we should
> - always store "result" in OUT and copy back the original input to IN
> - OR try to adhere the exchange pattern, and store "result" in either
> IN or OUT depending on the pattern.
>
> This is often only a matter when you send an Exchange to Camel. If you
> use the sendBody then Camel will extract
> the correct result and thus its not a problem here.
>
>
>
>
> --
> Claus Ibsen
> Apache Camel Committer
>
> Open Source Integration: http://fusesource.com
> Blog: http://davsclaus.blogspot.com/
> Twitter: http://twitter.com/davsclaus
>
--
Claus Ibsen
Apache Camel Committer
Open Source Integration: http://fusesource.com
Blog: http://davsclaus.blogspot.com/
Twitter: http://twitter.com/davsclaus
