Maximum Size When Parsing XML With DOM

Currently I'm implementing a REST client which shall parse the XML response messages. It is intended, later, to be running on an Android device. Thus, memory and processing speed i

Solution 1:

There are no standard limits set for XML documents or DOM size so it depends entirely on what the host machine can cope with.

As you are implementing on Android you should assume a pretty limited amount of memory, and remember the DOM, the XML parser, your program logic, the display logic, the JVM and Android itself all have to fit in the available memory!.

As a rule of thumb you can expect the DOM occupy memory about four times the size of the source XML document. So assume 512MB of available memory, aim to take no more than half of this for you DOM and you end up with 512/8 or a practical maximum of 64MB for the XML doc.

Just to be on the safe side I would half that again to a 32MB max. So if you expect many documents of this size I would swithc to SAX parsing!.

If you want the app to respond with any speed on large documents the SAX is the way to go. A SAX parser can start returning results as soon as the first element is read a DOM parser needs to read the whole document before any output can be sent to your program.

Solution 2:

My experience let me say that using DOM the memory used is 2x the file size, but of course it's just an indication. If the XML tree has just one field containing the entire data, the memory used is similar to file size!