Saving business objects into xml file

Question

I have the following XML file parsed into a DOM tree, with 2 different types of nodes "TestCase" and
"RealCase". Then I mapped each type to a different type of business object, TestCaseObj and RealCaseObj.
Now, there may be addition of new objects, or modifications to the data stored in the business objects
by my application. Eventually when I save the business objects back into the XML file, how should I go
about doing that?
<ROOT>
<TestCase TestID="T1">
     <Element1>Data1</Element1>
     <Element2>Data2</Element2>
</TestCase>
<TestCase TestID="T2">
     <Element1>Data1</Element1>
     <Element2>Data2</Element2>
</TestCase>
<RealCase ID="R1">
     <Element1>Data1</Element1>
     <Element2>Data2</Element2>
     <Element3>Data3</Element3>
</RealCase>
<RealCase ID="R2">
     <Element1>Data1</Element1>
     <Element2>Data2</Element2>
     <Element3>Data3</Element3>
</RealCase>
</ROOT>

Answer 1

The DocumentBuilder class does not allow you to parse a portion of the xmlfile. Therefore, it will not be possible to read "TestCase" into the DOM without bringing in "RealCase" nodes as well. As such, these codes will parse the entire xml file into DOM:
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document document = builder.parse( xmlFile );
However, your problem can be solved by reading only "TestCase" nodes in DOM, as follows:
NodeList elementNodeList =
elementNode.getElementsByTagName("TestCase");
Your codes will then change the data in the elementNodeList, without affecting "RealCase" although it is loaded into DOM. You can be sure that elementNodeList contains only "TestCase" nodes.
Once you have made your changes, save the DOM back to the XML file, using the serializer method as discussed earlier.
Good luck.