From: Alex Sherwin <alex.sherwin_at_acadiasoft.com>
Date: Fri, 9 Jan 2009 13:53:34 -0500

Aren't all of the underlying implementations boiling down to the same one,
which ends up using an InputStream from all of the wrappers/helpers that
allow for other types (String, File) etc?

 

I would think this is the case. and if it were, the timings should infact be
pretty close to identical

 

 

Alex Sherwin

alex.sherwin_at_acadiasoft.com

 

From: Forsberg, Mike [mailto:mike.forsberg_at_amd.com]
Sent: Friday, January 09, 2009 1:48 PM
To: users_at_jaxb.dev.java.net
Subject: Is unmarshalling from a file the same speed as a
ByteArrayInputStream?

 

I've seemed to have run across some interesting behavior in some code that
I've inherited.

 

Using the same unmashaller, the unmarshalling from a file appears to run in
the same time as unmarshalling of a string. I'm wondering if someone could
shed some information on why this is happening.

 

Consider the following code.

 

Temp file based unmarshalling (What I would consider bad mojo)

 

// exceptions are simplified for this example.

Public Model unmarshallModelViaFile(String xmlString) throws Exception {

    File f = File.createTempFile("tempFile", ".xml", tmpDir);

    FileWriter fw = new FileWriter(f);

    fw.write(xmlString);

    fw.close();

    Model model = (Model) modelUnmarshaller.unmarshal(f);

    return model;

}

 

String based unmarshalling... (What I think we should do)

 

// exceptions are simplified for this example.

Public Model unmarshallModel(String xmlString) throws Exception {

    Model model = (Model) modelUnmarshaller.unmarshal(new
ByteArrayInputStream(xmlString.getBytes()));

    return model;

}

 

When I run these two functions in a loop of 1000 times, they only vary in
time by 1%.

 

My timing code.

 

long fileStart = System.currentTimeMillis();

for (int i = 0; i < 1000; i++) {

    Model model2 = marshaller.unmarshallModelViaFile(contentsOfFile);

}

long fileDuration = System.currentTimeMillis() - fileStart;

System.out.println("fileDuration : " + fileDuration);

 

Same timing code for the String based version.

 

Could someone inform me why the elapsed time of the two methods is so
similar?

 

Mike Forsberg
Factory Automation Engineer II
TDG - MST - MS - ACS
T 512.602.0220