How can I have JAXB call a method after it has completed unmarshalling an XML file into an object?

Question

I am using JAXB to unmarshall an XML file into a Java object -- standard stuff. Once JAXB has completed this, I'd like a method to be called on the newly created object.

Is there a mechanism to do this? I'd prefer the object, not an external entity, do this to keep construction in one place.

Thanks.

Answer 1

To be able to execute code after unmarshalling took place, you need an Unmarshaller-Listener

However, I'm not sure, if the listener is invoked after the properties are set or before.

NOTE: The listener is available since JAXB-2.0 (JDK-6)

Answer 2

You can simple add the following method to your object definition:

void afterUnmarshal(Unmarshaller u, Object parent) {
  ...
}

It will be called once the current object has been completely deserialized. See also the documentation about unmarshalling callbacks

Answer 3

In addition to the Unmarshaller.Listener you can add the following methods to your domain model classes themselves.

• public void beforeUnmarshal(Unmarshaller unmarshaller, Object parent)
• public void afterUnmarshal(Unmarshaller unmarshaller, Object parent)

From: http://java.sun.com/javase/6/docs/api/javax/xml/bind/Unmarshaller.Listener.html