nu.xom

Class XPathContext

Object

nu.xom.XPathContext

public final class XPathContext
extends Object

Provides namespace prefix bindings for use in an XPath expression.

Version:

1.3.1

Author:

Elliotte Rusty Harold

Constructor Summary

Constructors

Constructor and Description
XPathContext() Creates a new XPath context that binds the xml prefix to the URI http://www.w3.org/XML/1998/namespace.
XPathContext(String prefix, String uri) Creates a new XPath context that binds the specified prefix to the specified URI.

Method Summary

Modifier and Type	Method and Description
void	addNamespace(String prefix, String uri) Binds the specified prefix to the specified namespace URI.
String	lookup(String prefix) Returns the namespace URI associated with a specified prefix in this context.
static XPathContext	makeNamespaceContext(Element element) Creates a new XPath context that contains all the namespace bindings in scope on the element.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

XPathContext

public XPathContext(String prefix,
                    String uri)

Creates a new XPath context that binds the specified prefix to the specified URI. The xml prefix is also bound to the URI http://www.w3.org/XML/1998/namespace.

Parameters:

prefix - the prefix to bind

uri - the namespace URI the prefix is bound to

XPathContext

public XPathContext()

Creates a new XPath context that binds the xml prefix to the URI http://www.w3.org/XML/1998/namespace.

Method Detail

addNamespace

public void addNamespace(String prefix,
                         String uri)

Binds the specified prefix to the specified namespace URI. If the prefix is already bound in this context, the new URI replaces the old URI. Binding a prefix to null removes the declaration. The binding of the xml prefix may not be changed.

Parameters:

prefix - the prefix to bind

uri - the namespace URI the prefix is bound to

Throws:

NamespaceConflictException - if the prefix is xml and the URI is not http://www.w3.org/XML/1998/namespace or the prefix is the empty string

NullPointerException - if the prefix is null

makeNamespaceContext

public static XPathContext makeNamespaceContext(Element element)

Creates a new XPath context that contains all the namespace bindings in scope on the element. Changing the prefixes in scope on the element after the context is returned does not change the context.

Parameters:

element - the element whose namespace bindings are copied

Returns:

all the namespace prefix mappings in scope on the element

lookup

public String lookup(String prefix)

Returns the namespace URI associated with a specified prefix in this context. It returns null if this prefix is not bound to a namespace in this context. The prefix is not checked for validity. If you pass in a prefix that is not an NCName, this method simply returns null.

Parameters:

prefix - the prefix to look up

Returns:

the namespace URI associated with the specified prefix in this context or null