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Quickest way to create objects from XML....

Landon Blake
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Joined: Dec 04, 2003
Posts: 121
I am storing the persistent state of thousands of objects for an application in XML. I need to know which of the following 2 methods ould be the fast way to create the objects in memory from the xml representations:

Method #1: Each object is represented in a separate XML text file. The application searches for the object representation based on the name of the XML file. It finds the correct XML file, opens a stream to that file, reads the content, and creates the object in memory using the info in the XML file.

Method #2: Objects are grouped together in a single, massive XML file. Each object is represented by a node or element in the XML file, and each node or element is uniquely identified. The application uses a pull XML parser the read through the file until it reaches the desired node, and uses the information in this node to create the object in memory.


[ July 06, 2005: Message edited by: Landon Blake ]
Joe Ess

Joined: Oct 29, 2001
Posts: 9189

I'm tempted to say that it would be practical tie, but given that Method #1 doesn't do any parsing (rather slow) until it has the file/object it's looking for and Method #2 would be parsing a large file, I'd guess that Method #1 would be faster, the difference increasing as the number of objects grows.
Disclaimer: Performance depends on a LOT of variables. There's only one way to be sure: Read Java Platform Performance, write both schemes and test, test, test.
Faster still would be to have some sort of in-order index file of the value you are searching on. You could do a binary search of the file using RandomAccessFile. Associated with the index could either a file name or an index into the huge file. Doing a linear search of anything more than a few values will be a big performance drain (see Disclaimer, above).

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