Module java.xml
Package javax.xml.namespace

Interface NamespaceContext

public interface NamespaceContext
Interface for read only XML Namespace context processing.

An XML Namespace has the properties:

  • Namespace URI: Namespace name expressed as a URI to which the prefix is bound
  • prefix: syntactically, this is the part of the attribute name following the XMLConstants.XMLNS_ATTRIBUTE ("xmlns") in the Namespace declaration

example: <element xmlns:prefix="http://Namespace-name-URI">

All get*(*) methods operate in the current scope for Namespace URI and prefix resolution.

Note that a Namespace URI can be bound to multiple prefixes in the current scope. This can occur when multiple XMLConstants.XMLNS_ATTRIBUTE ("xmlns") Namespace declarations occur in the same Start-Tag and refer to the same Namespace URI. e.g.

 
 <element xmlns:prefix1="http://Namespace-name-URI"
          xmlns:prefix2="http://Namespace-name-URI">
This can also occur when the same Namespace URI is used in multiple XMLConstants.XMLNS_ATTRIBUTE ("xmlns") Namespace declarations in the logical parent element hierarchy. e.g.
 
 <parent xmlns:prefix1="http://Namespace-name-URI">
   <child xmlns:prefix2="http://Namespace-name-URI">
     ...
   </child>
 </parent>

A prefix can only be bound to a single Namespace URI in the current scope.

Since:
1.5
See Also:
javax.xml.XMLConstants for declarations of common XML values, XML Schema Part2: Datatypes, Namespaces in XML

  • Method Summary

    Modifier and Type Method Description
    String getNamespaceURI​(String prefix)
    Get Namespace URI bound to a prefix in the current scope.
    String getPrefix​(String namespaceURI)
    Get prefix bound to Namespace URI in the current scope.
    Iterator<String> getPrefixes​(String namespaceURI)
    Get all prefixes bound to a Namespace URI in the current scope.

  • Method Details

    • getNamespaceURI

      String getNamespaceURI​(String prefix)
      Get Namespace URI bound to a prefix in the current scope.

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

      Return value for specified prefixes
      prefix parameter Namespace URI return value
      DEFAULT_NS_PREFIX ("") default Namespace URI in the current scope or XMLConstants.NULL_NS_URI("") when there is no default Namespace URI in the current scope
      bound prefix Namespace URI bound to prefix in current scope
      unbound prefix XMLConstants.NULL_NS_URI("")
      XMLConstants.XML_NS_PREFIX ("xml") XMLConstants.XML_NS_URI ("http://www.w3.org/XML/1998/namespace")
      XMLConstants.XMLNS_ATTRIBUTE ("xmlns") XMLConstants.XMLNS_ATTRIBUTE_NS_URI ("http://www.w3.org/2000/xmlns/")
      null IllegalArgumentException is thrown

      Parameters:
      prefix - prefix to look up
      Returns:
      Namespace URI bound to prefix in the current scope
      Throws:
      IllegalArgumentException - When prefix is null

    • getPrefix

      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:

      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
      Throws:
      IllegalArgumentException - When namespaceURI is null

    • getPrefixes

      Iterator<String> getPrefixes​(String namespaceURI)
      Get all prefixes bound to a Namespace URI in the current scope.

      An Iterator over String elements is returned in an arbitrary, implementation dependent, order.

      The Iterator is not modifiable. e.g. the remove() method will throw UnsupportedOperationException.

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

      Return value for specified Namespace URIs
      Namespace URI parameter prefixes value returned
      bound Namespace URI, including the <default Namespace URI> Iterator over prefixes bound to Namespace URI in the current scope in an arbitrary, implementation dependent, order
      unbound Namespace URI empty Iterator
      XMLConstants.XML_NS_URI ("http://www.w3.org/XML/1998/namespace") Iterator with one element set to XMLConstants.XML_NS_PREFIX ("xml")
      XMLConstants.XMLNS_ATTRIBUTE_NS_URI ("http://www.w3.org/2000/xmlns/") Iterator with one element set to XMLConstants.XMLNS_ATTRIBUTE ("xmlns")
      null IllegalArgumentException is thrown

      Parameters:
      namespaceURI - URI of Namespace to lookup
      Returns:
      Iterator for all prefixes bound to the Namespace URI in the current scope
      Throws:
      IllegalArgumentException - When namespaceURI is null