11.5.1 Using onWhen - Example does not work

[PascalSchumacher]

The example in section 11.5.1 "Using onWhen" on page 510:

public final class MyHttpUtil {
    public static boolean isIllegalDataError(
        HttpOperationFailedException cause) {
        int code = cause.getStatusCode();
        if (code != 500) {
            return false;
        }
        return "ILLEGAL DATA".equals(cause.getResponseBody().toString());
    }
}

onException(HttpOperationFailedException.class)
    .onWhen(bean(MyHttpUtil.class, "isIllegalData"))
    .handled(true)
    .to("file:/rider/files/illegal");

does not work (at least as with Camel version 2.23.0) as demonstrated by this test:

public class OnWhenBindMethodWithExceptionSubclassParameterTest extends CamelTestSupport {

    public static final class MyHttpUtil {
        public static boolean isIllegalDataError(HttpOperationFailedException cause) {
            int code = cause.getStatusCode();
            if (code != 500) {
                return false;
            }
            return "ILLEGAL DATA".equals(cause.getResponseBody().toString());
        }
    }

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {

            public void configure() {
                onException(HttpOperationFailedException.class)
                    .onWhen(bean(MyHttpUtil.class, "isIllegalDataError"))
                    .handled(true)
                    .to("mock:illegal");

                from("seda:start")
                    .process(e -> { 
                        throw new HttpOperationFailedException("", 500, "", "", null, "ILLEGAL DATA");
                    });
            }
        };
    }

    @Test
    public void test() throws Exception {
        getMockEndpoint("mock:illegal").expectedMessageCount(1);

        template.sendBody("seda:start", "Hello World");

        assertMockEndpointsSatisfied();
    }
}

I reported this behavior as https://issues.apache.org/jira/browse/CAMEL-12949 - "onWhen predicate with onException can not bind to method with exception subclass parameter", but the issue was rejected as "Won't Fix". Therefore the error lies with this example.

[PascalSchumacher]

Discovered that the example works if you annotate the HttpOperationFailedException parameter with @ExchangeException.

This test passes:

public class OnWhenCamelInActionBugTest extends CamelTestSupport {

    public static final class MyHttpUtil {
        public static boolean isIllegalDataError(@ExchangeException HttpOperationFailedException cause) {
            int code = cause.getStatusCode();
            if (code != 500) {
                return false;
            }
            return "ILLEGAL DATA".equals(cause.getResponseBody().toString());
        }
    }

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {

            public void configure() {
                onException(HttpOperationFailedException.class)
                    .onWhen(bean(MyHttpUtil.class, "isIllegalDataError"))
                    .handled(true)
                    .to("mock:illegal");

                from("seda:start")
                    .process(e -> { 
                        throw new HttpOperationFailedException("", 500, "", "", null, "ILLEGAL DATA");
                    });
            }
        };
    }

    @Test
    public void test() throws Exception {
        getMockEndpoint("mock:illegal").expectedMessageCount(1);

        template.sendBody("seda:start", "Hello World");

        assertMockEndpointsSatisfied();
    }
}

[davsclaus]

Thanks for reporting

[davsclaus]

I added this to the errata

[PascalSchumacher]

Thanks!

A small nitpick:

The line:

.onWhen(bean(MyHttpUtil.class, "isIllegalData"))

should be changed to:

.onWhen(bean(MyHttpUtil.class, "isIllegalDataError"))

to match the method name MyHttpUtil#isIllegalDataError.

[davsclaus]

Thanks I just updated the errata with that info as well