The DOMSource class allows the client of the implementation of this API to specify a DOM Node as the source of the input tree. The model of how the Transformer deals with the DOM tree in terms of mismatches with the XSLT data model or other data models is beyond the scope of this document. Any of the nodes derived from Node are legal input.

The DOMResult class allows a Node to be specified to which result DOM nodes will be appended. If an output node is not specified, the transformer will use DocumentBuilder.newDocument() to create an output Document node. If a node is specified, it should be one of the following: Document, Element, or DocumentFragment. Specification of any other node type is implementation dependent and undefined by this API. If the result is a Document, the output of the transformation must have a single element root to set as the document element.

The DOMLocator node may be passed to TransformerException objects, and retrieved by trying to cast the result of the TransformerException.getLocator() method. The implementation has no responsibility to use a DOMLocator instead of a SourceLocator (though line numbers and the like do not make much sense for a DOM), so the result of getLocator must always be tested with an instanceof.