Spring Integration here. I was expecting to see a normalize(...) method off the IntegrationFlow DSL and was surprised to find there wasn't one (like .route(...) or .aggregate(...), etc.).
In fact, some digging on Google and the Spring Integration docs, and I can't seem to find any built-in support for the Normalizer EIP. So I've taken a crack at my own:
public class Normalizer extends AbstractTransformer {
private Class<?> targetClass;
private GenericConverter genericConverter;
public Normalizer(Class<?> targetClass, GenericConverter genericConverter) {
Optional<GenericConverter.ConvertiblePair> maybePair = genericConverter.getConvertibleTypes().stream()
.filter(convertiblePair -> !convertiblePair.getTargetType().equals(targetClass))
.findAny();
assert(maybePair.isEmpty());
this.targetClass = targetClass;
this.genericConverter = genericConverter;
}
@Override
protected Object doTransform(Message<?> message) {
Object inbound = message.getPayload();
return genericConverter.convert(inbound, TypeDescriptor.forObject(inbound), TypeDescriptor.valueOf(targetClass));
}
}
The idea is that Spring already provides the GenericConverter SPI for converting multiple source types to 1+ target type instance. We just need a specialized flavor of that that has the same target type for all convertible pairings. So here we extend AbstractTransformer and pass it one of these GenericConverters to use. During initialization we just verify that all the possible convertible pairs convert to the same targetClass specified for the Normalizer.
The idea is I could instantiate it like so:
@Bean
public Normalizer<Fizz> fizzNormalizer(GenericConverter fizzConverter) {
return new Normalizer(Fizz.class, fizzConverter);
}
And then put it in a flow:
IntegrationFlow someFlow = IntegrationFlows.from(someChannel())
.transform(fizzNormalizer())
// other components
.get();
While I believe this will work, before I start using it too heavily I want to make sure I'm not overlooking anything in the Spring Integration framework that will accomplish/satisfy the Normalizer EIP for me. No point in trying to reinvent the wheel and all that jazz. Thanks for any insight.
