Parsing very large XML documents (and a bit more) in java

Question

(All of the following is to be written in Java)

I have to build an application that will take as input XML documents that are, potentially, very large. The document

Answer 1

I would write a custom implementation of InputStream that decrypts the bytes in the file and then use SAX to parse the resulting XML as it comes off the stream.

SAXParserFactory.newInstance().newSAXParser().parse(
  new DecryptingInputStream(), 
  new MyHandler()
);