After a bunch of digging and headaches, I ended up developing a solution.
Step 1 (optional)
EDIT: You don't have to patch Jersey to achieve this behavior. I cannot find it documented anywhere, but the org.glassfish.jersey.internal.inject.Custom annotation marks a provider as custom (whereas @Provider alone is insufficient). You also have to disable MOXy by setting CommonProperties.MOXY_JSON_FEATURE_DISABLE to true if your provider is for application/json. Thus you only have to do:
@Custom
@Provider
public class MyCustomMessageBodyReader...
[...]
This is my least favorite part of my solution, but also saved me from a bunch of code duplication. Jersey's sorting algorithm for selecting MessageBodyReader/Writers has no way to prioritize application providers (that I could find). I wanted to extend AbstractRootElementJaxbProvider to re-use its functionality, but that meant I couldn't make it more specific than the Jersey-provided XmlRootElementJaxbProvider. Since by default Jersey only sorts on media type distance, object type distance, and whether a provider is registered as a custom provider (providers detected via the @Provider annotation aren't registered as custom providers), the Jersey implementation would always be selected instead of my MessageBodyReader/Writer.
I checked out the Jersey 2.10.4 source from Github and patched MessageBodyFactory to utilize @Priority annotations as part of the selection algorithm for MessageBodyReader/Writers.
diff --git a/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java b/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java
index 3845b0c..110f18c 100644
--- a/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java
+++ b/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java
@@ -72,6 +72,7 @@ import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.ReaderInterceptor;
import javax.ws.rs.ext.WriterInterceptor;
+import javax.annotation.Priority;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.xml.transform.Source;
@@ -107,6 +108,8 @@ import jersey.repackaged.com.google.common.primitives.Primitives;
*/
public class MessageBodyFactory implements MessageBodyWorkers {
+ private static final int DEFAULT_WORKER_PRIORITY = 1000;
+
private static final Logger LOGGER = Logger.getLogger(MessageBodyFactory.class.getName());
/**
@@ -218,13 +221,15 @@ public class MessageBodyFactory implements MessageBodyWorkers {
public final T provider;
public final List<MediaType> types;
public final Boolean custom;
+ public final int priority;
public final Class<?> providerClassParam;
protected WorkerModel(
- final T provider, final List<MediaType> types, final Boolean custom, Class<T> providerType) {
+ final T provider, final List<MediaType> types, final Boolean custom, final int priority, Class<T> providerType) {
this.provider = provider;
this.types = types;
this.custom = custom;
+ this.priority = priority;
this.providerClassParam = getProviderClassParam(provider, providerType);
}
@@ -239,8 +244,8 @@ public class MessageBodyFactory implements MessageBodyWorkers {
private static class MbrModel extends WorkerModel<MessageBodyReader> {
- public MbrModel(MessageBodyReader provider, List<MediaType> types, Boolean custom) {
- super(provider, types, custom, MessageBodyReader.class);
+ public MbrModel(MessageBodyReader provider, List<MediaType> types, Boolean custom, int priority) {
+ super(provider, types, custom, priority, MessageBodyReader.class);
}
public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
@@ -263,8 +268,8 @@ public class MessageBodyFactory implements MessageBodyWorkers {
private static class MbwModel extends WorkerModel<MessageBodyWriter> {
- public MbwModel(MessageBodyWriter provider, List<MediaType> types, Boolean custom) {
- super(provider, types, custom, MessageBodyWriter.class);
+ public MbwModel(MessageBodyWriter provider, List<MediaType> types, Boolean custom, int priority) {
+ super(provider, types, custom, priority, MessageBodyWriter.class);
}
public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
@@ -437,6 +442,10 @@ public class MessageBodyFactory implements MessageBodyWorkers {
if (modelA.custom ^ modelB.custom) {
return (modelA.custom) ? -1 : 1;
}
+
+ if(modelA.priority != modelB.priority) {
+ return modelA.priority - modelB.priority;
+ }
return 0;
}
@@ -578,17 +587,27 @@ public class MessageBodyFactory implements MessageBodyWorkers {
}
}
+ private static int getPriority(Priority annotation) {
+ if (annotation == null) {
+ return DEFAULT_WORKER_PRIORITY;
+ }
+
+ return annotation.value();
+ }
+
private static void addReaders(List<MbrModel> models, Set<MessageBodyReader> readers, boolean custom) {
for (MessageBodyReader provider : readers) {
+ int priority = getPriority(provider.getClass().getAnnotation(Priority.class));
List<MediaType> values = MediaTypes.createFrom(provider.getClass().getAnnotation(Consumes.class));
- models.add(new MbrModel(provider, values, custom));
+ models.add(new MbrModel(provider, values, custom, priority));
}
}
private static void addWriters(List<MbwModel> models, Set<MessageBodyWriter> writers, boolean custom) {
for (MessageBodyWriter provider : writers) {
+ int priority = getPriority(provider.getClass().getAnnotation(Priority.class));
List<MediaType> values = MediaTypes.createFrom(provider.getClass().getAnnotation(Produces.class));
- models.add(new MbwModel(provider, values, custom));
+ models.add(new MbwModel(provider, values, custom, priority));
}
}
After building Jersey, I replaced the jersey-common jar in the Glassfish modules directory with my patched version. This let me annotate my MessageBodyReader/Writers with @Priority(500) and have them be selected by Jersey.
I felt that this was the cleanest way to let me prioritize my MessageBodyReader/Writers without affecting anything else in Glassfish that relies on Jersey.
Step 2
Inspired by this post I decided that using an Unmarshaller.Listener would be cleaner than my original path of implementing afterUnmarshal on each of my JAXB classes. I made an interface (CanBeValidated) and extended Unmarshaller.Listener as follows.
public final class ValidatingUnmarshallerListener
extends Unmarshaller.Listener
{
private final ValidationEventHandler validationEventHandler;
public ValidatingUnmarshallerListener(
ValidationEventHandler validationEventHandler)
{
this.validationEventHandler = validationEventHandler;
}
@Override
public void afterUnmarshal(Object target, Object parent)
{
if (target == null
|| !(target instanceof CanBeValidated))
{
return;
}
CanBeValidated v = (CanBeValidated) target;
Collection<Throwable> validationErrors = v.validate();
for (Throwable t : validationErrors)
{
ValidationEvent event = new ValidationEventImpl(
ValidationEvent.ERROR,
t.getLocalizedMessage(),
null,
t);
this.validationEventHandler.handleEvent(event);
}
}
}
Step 3
Finally, I extended org.glassfish.jersey.message.internal.AbstractRootElementJaxbProvider to override the readFrom method.
@Override
protected Object readFrom(
Class<Object> type,
MediaType mediaType,
Unmarshaller u,
InputStream entityStream)
throws JAXBException
{
final SAXSource source = getSAXSource(spf.provide(), entityStream);
ValidationEventCollector eventCollector = new ValidationEventCollector();
ValidatingUnmarshallerListener listener = new ValidatingUnmarshallerListener(eventCollector);
u.setEventHandler(eventCollector);
u.setListener(listener);
final Object result;
if (type.isAnnotationPresent(XmlRootElement.class))
{
result = u.unmarshal(source);
}
else
{
result = u.unmarshal(source, type).getValue();
}
if (eventCollector.hasEvents())
{
HttpError error = new HttpError(Response.Status.BAD_REQUEST);
for (ValidationEvent event : eventCollector.getEvents())
{
error.addMessage(ValidationUtil.toString(event));
}
throw new WebApplicationException(error.toResponse());
}
return result;
}
