Class NSFilter

This filter ensures that element and attribute names are properly prefixed, and that such prefixes are declared. Such data is critical for operations like writing XML text, and validating against DTDs: names or their prefixes may have been discarded, although they are essential to the exchange of information using XML. There are various common ways that such data gets discarded:

• By default, SAX2 parsers must discard the "xmlns*" attributes, and may also choose not to report properly prefixed names for elements or attributes. (Some parsers may support changing the namespace-prefixes value from the default to true, effectively eliminating the need to use this filter on their output.)
• When event streams are generated from a DOM tree, they may have never have had prefixes or declarations for namespaces; or the existing prefixes or declarations may have been invalidated by structural modifications to that DOM tree.
• Other software writing SAX event streams won't necessarily be worrying about prefix management, and so they will need to have a transparent solution for managing them.

This filter uses a heuristic to choose the prefix to assign to any particular name which wasn't already corectly prefixed. The associated namespace will be correct, and the prefix will be declared. Original structures facilitating text editing, such as conventions about use of mnemonic prefix names or the scoping of prefixes, can't always be reconstructed after they are discarded, as strongly encouraged by the current SAX2 defaults.

Note that this can't possibly know whether values inside attribute value or document content involve prefixed names. If your application requires using prefixed names in such locations you'll need to add some appropriate logic (perhaps adding additional heuristics in a subclass).

public NSFilter(EventConsumer next)

public void endDocument()
            throws SAXException

public void endElement(String uri,
                       String localName,
                       String qName)
            throws SAXException

public void endPrefixMapping(String prefix)
            throws SAXException

public void startDocument()
            throws SAXException

public void startElement(String uri,
                         String localName,
                         String qName,
                         Attributes atts)
            throws SAXException

public void startPrefixMapping(String prefix,
                               String uri)
            throws SAXException