/*
* $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/NamespaceContext.java,v 1.9 2006/02/05 21:47:41 elharo Exp $
* $Revision: 1.9 $
* $Date: 2006/02/05 21:47:41 $
*
* ====================================================================
*
* Copyright 2000-2002 bob mcwhirter & James Strachan.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of the Jaxen Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* ====================================================================
* This software consists of voluntary contributions made by many
* individuals on behalf of the Jaxen Project and was originally
* created by bob mcwhirter <bob@werken.com> and
* James Strachan <jstrachan@apache.org>. For more information on the
* Jaxen Project, please see <http://www.jaxen.org/>.
*
* $Id: NamespaceContext.java,v 1.9 2006/02/05 21:47:41 elharo Exp $
*/
package org.orbeon.jaxen;
/** Resolves namespace prefixes to namespace URIs.
*
* <p>
* The prefixes used within an XPath expression are
* independent of those used within any target document.
* When evaluating an XPath against a document, only
* the resolved namespace URIs are compared, not their
* prefixes.
* </p>
*
* <p>
* A <code>NamespaceContext</code> is responsible for
* translating prefixes as they appear in XPath expressions
* into URIs for comparison. A document's prefixes are
* resolved internal to the document based upon its own
* namespace nodes.
* </p>
*
* @see BaseXPath
* @see Navigator#getElementNamespaceUri
* @see Navigator#getAttributeNamespaceUri
*
* @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
*/
public interface NamespaceContext
{
/** Translate the provided namespace prefix into
* the matching bound namespace URI.
*
* <p>
* In XPath, there is no such thing as a 'default namespace'.
* The empty prefix <strong>always</strong> resolves to the empty
* namespace URI. This method should return null for the
* empty prefix.
* Similarly, the prefix "xml" always resolves to
* the URI "http://www.w3.org/XML/1998/namespace".
* </p>
*
* @param prefix the namespace prefix to resolve
*
* @return the namespace URI bound to the prefix; or null if there
* is no such namespace
*/
String translateNamespacePrefixToUri(String prefix);
}