I'm about to delete certain elements in an XML document, using code like the following:
NodeList nodes = ...;
for (int i = 0; i < nodes.getLength(); i++) {
Element e = (Element)nodes.item(i);
if (certain criteria involving Element e) {
e.getParentNode().removeChild(e);
}
}
Will this interfere with proper traversal of the NodeList? Any other caveats with this approach? If this is totally wrong, what's the proper way to do it?
As already mentioned, removing an element reduces the size of the list but the counter is still increasing (i++):
[element 1] <- Delete
[element 2]
[element 3]
[element 4]
[element 5]
[element 2]
[element 3] <- Delete
[element 4]
[element 5]
--
[element 2]
[element 4]
[element 5] <- Delete
--
--
[element 2]
[element 4]
--
--
--
The simplest solution, in my opinion, would be to remove i++ section in the loop and do it as needed when the iterated element was not deleted.
NodeList nodes = ...;
for (int i = 0; i < nodes.getLength();) {
Element e = (Element)nodes.item(i);
if (certain criteria involving Element e) {
e.getParentNode().removeChild(e);
} else {
i++;
}
}
Pointer stays on the same place when the iterated element was deleted. The list shifts by itself.
[element 1] <- Delete
[element 2]
[element 3]
[element 4]
[element 5]
[element 2] <- Leave
[element 3]
[element 4]
[element 5]
--
[element 2]
[element 3] <- Leave
[element 4]
[element 5]
--
[element 2]
[element 3]
[element 4] <- Delete
[element 5]
--
[element 2]
[element 3]
[element 5] <- Delete
--
--
[element 2]
[element 3]
--
--
--
At the end, you must update the XML file within the path of your project.
TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer transformer = transFactory.newTransformer();
DOMSource source = new DOMSource(documentoXml);
StreamResult result = new StreamResult(new File(path + "\\resources\\xml\\UsuariosFile.xml"));
transformer.transform(source, result);
if you do not put these lines, your file will not be updated