Validation using JAXB and Stax to marshal XML document

I have created an XML schema (foo.xsd) and used `xjc` to create my binding classes for JAXB. Let's say the root element is `collection` and I am writing N `document` objects, which are complex types. Because I plan to write out large XML files, I am using Stax to write out the `collection` root element, and JAXB to marshal document subtrees using `Marshaller.marshal(JAXBElement, XMLEventWriter)`. This is the approach recommended by jaxb's unofficial user's guide. My question is, how can I validate the XML while it's being marshalled? If I bind a schema to the JAXB marshaller (using `Marshaller.setSchema()`), I get validation errors because I am only marshalling a subtree (it's complaining that it's not seeing the `collection` root element"). I suppose what I really want to do is bind a schema to the `Stax XMLEventWriter` or something like that. Any comments on this overall approach would be helpful. Basically I want to be able to use `JAXB` to marshal and unmarshal large XML documents without running out of memory, so if there's a better way to do this let me know.