t777 t777 - 9 days ago 5
Java Question

Jersey: How to use a custom `ExceptionMapperFactory`

I need to use a custom

ExceptionMapperFactory
to implement a custom
find()
logic.

public class MyExceptionMapperFactory extends ExceptionMapperFactory {

// [...]

@Override
public <T extends Throwable> ExceptionMapper<T> find(Class<T> type) {
// [...]
}
}


How can I use/register it?

Registering it in my RestApplication has no effect:

public class RestApplication extends ResourceConfig {

public RestApplication() {
register(JacksonFeature.class);
register(JacksonXMLProvider.class);

register(MyExceptionMapperFactory.class);
register(SomeExceptionMapper.class, 600);
register(OtherExceptionMapper.class, 550);

// [...]
}
}


Any ideas? TIA!

Answer

I've never implemented this, so I don't know all the nuances, but briefly looking at the source and the tests, it looks like you just need to hook it up to the DI system

register(new AbstractBinder() {
    @Override
    public void configure() {
        bindAsContract(MyExceptionMapperFactory.class)
                .to(ExceptionMappers.class)
                .in(Singleton.class);
    }
})

Not sure how to disable the original one, but if it is still being used, you can try to set a rank for your factory so that when it's looked up, yours will take precedence

bindAsContract(MyExceptionMapperFactory.class)
        .to(ExceptionMappers.class)
        .ranked(Integer.MAX_VALUE)
        .in(Singleton.class);

UPDATE

It seems the following will remove the original factory, since the ranking doesn't work

@Provider
public class ExceptionMapperFactoryFeature implements Feature {

    @Override
    public boolean configure(FeatureContext context) {
        final ServiceLocator locator = ServiceLocatorProvider.getServiceLocator(context);
        final Descriptor<?> descriptor = locator.getBestDescriptor(new Filter() {
            @Override
            public boolean matches(Descriptor d) {
                return d.getImplementation().equals(ExceptionMapperFactory.class.getName());
            } 
        });
        ServiceLocatorUtilities.removeOneDescriptor(locator, descriptor);

        context.register(new AbstractBinder() {
            @Override
            public void configure() {
                bindAsContract(MyExceptionMapperFactory.class)
                        .to(ExceptionMappers.class)
                        .in(Singleton.class);
            }
        });
        return true;
    }
}
Comments