具有XML模式的增强XML

Question

javax.xml.validation.Validator has a method to validate and augment xml against a schema.

Simplified xml:

<something>
  <sub1>false</sub1> <!-- Suppose sub1 is optional and may not be present in xml -->
  <sub2>false</sub2>
</something>

Simplified xsd:

<complexType name="something">
  <sequence>
    <element name="sub1" type="boolean" maxOccurs="1" minOccurs="0" default="false"/>
    <element name="sub2" type="boolean" maxOccurs="1" minOccurs="1"/>
  </sequence>
</complexType>

Simplified validation and augmentation code:

Schema schema = schemaFactory.newSchema(schemaFile);
Validator validator = schema.newValidator();

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);

DocumentBuilder builder = factory.newDocumentBuilder();

Document document = builder.parse(new File(xmlFile));
DOMSource input = new DOMSource(document);
DOMResult output = new DOMResult();
validator.validate(input, output);

Document result = (Document)output.getNode();

So, besides validating xml against the schema, it should also augment it and add any missing defaults (like sub1) and send that into output .

However, sub1 is not present in result when it is missing in xml.

Where am I off track here?

EDIT:

Ok, found the reason why sub1 is missing. But how can I ensure that sub1 is present in result even when it's not in xml?

Answer 1

This answer quotes the spec: augmentation applies default values to empty elements. It does NOT add elements that are not present in xml.

In other words, augmentation by schema cannot guarantee that elements are present.