public abstract String getPrefix (String namespaceURI)

Get prefix bound to Namespace URI in the current scope.

To get all prefixes bound to a Namespace URI in the current scope, use getPrefixes(String namespaceURI).

When requesting a prefix by Namespace URI, the following table describes the returned prefix value for all Namespace URI values:

getPrefix(namespaceURI) return value for specified Namespace URIs
Namespace URI parameter prefix value returned
<default Namespace URI> XMLConstants.DEFAULT_NS_PREFIX ("")
bound Namespace URI prefix bound to Namespace URI in the current scope, if multiple prefixes are bound to the Namespace URI in the current scope, a single arbitrary prefix, whose choice is implementation dependent, is returned
unbound Namespace URI null
XMLConstants.XML_NS_URI ("http://www.w3.org/XML/1998/namespace") XMLConstants.XML_NS_PREFIX ("xml")
XMLConstants.XMLNS_ATTRIBUTE_NS_URI ("http://www.w3.org/2000/xmlns/") XMLConstants.XMLNS_ATTRIBUTE ("xmlns")
null IllegalArgumentException is thrown

Parameters:
namespaceURI    URI of Namespace to lookup

Returns:  prefix bound to Namespace URI in current context

Exceptions:
IllegalArgumentException    When namespaceURI is null