/*
* $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NamespaceUriFunction.java,v 1.13 2006/02/05 21:47:41 elharo Exp $
* $Revision: 1.13 $
* $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: NamespaceUriFunction.java,v 1.13 2006/02/05 21:47:41 elharo Exp $
*/
package org.orbeon.jaxen.function;
import org.orbeon.jaxen.Context;
import org.orbeon.jaxen.Function;
import org.orbeon.jaxen.FunctionCallException;
import org.orbeon.jaxen.Navigator;
import java.util.List;
/**
* <p>
* <b>4.1</b>
* <code><i>string</i> namespace-uri(<i>node-set?</i>)</code>
* </p>
*
* <blockquote src="http://www.w3.org/TR/xpath">
* <p>
* The <b>namespace-uri</b>
* function returns the namespace URI of the <a
* href="http://www.w3.org/TR/xpath#dt-expanded-name" target="_top">expanded-name</a> of the node in the
* argument node-set that is first in <a
* href="http://www.w3.org/TR/xpath#dt-document-order" target="_top">document order</a>. If the argument
* node-set is empty, the first node has no <a
* href="http://www.w3.org/TR/xpath#dt-expanded-name" target="_top">expanded-name</a>, or the namespace URI of
* the <a href="http://www.w3.org/TR/xpath#dt-expanded-name" target="_top">expanded-name</a> is null, an empty
* string is returned. If the argument is omitted, it defaults to a
* node-set with the context node as its only member.
* </p>
*
* <blockquote> <b>NOTE: </b>The string returned by the <b>namespace-uri</b> function will
* be empty except for element nodes and attribute nodes.</blockquote>
*
* </blockquote>
*
* @author bob mcwhirter (bob @ werken.com)
* @see <a href="http://www.w3.org/TR/xpath#function-namespace-uri"
* target="_top">Section 4.1 of the XPath Specification</a>
*/
public class NamespaceUriFunction implements Function
{
/**
* Create a new <code>NamespaceUriFunction</code> object.
*/
public NamespaceUriFunction() {}
/**
* Returns the namespace URI of the specified node or the namespace URI of the context node if
* no arguments are provided.
*
* @param context the context at the point in the
* expression where the function is called
* @param args a <code>List</code> containing zero or one items
*
* @return a <code>String</code> containing the namespace URI
*
* @throws FunctionCallException if <code>args</code> has more than one item
*/
public Object call(Context context,
List args) throws FunctionCallException
{
if (args.size() == 0)
{
return evaluate( context.getNodeSet(),
context.getNavigator() );
}
if ( args.size() == 1 )
{
return evaluate( args,
context.getNavigator() );
}
throw new FunctionCallException( "namespace-uri() requires zero or one argument." );
}
/**
* Returns the namespace URI of <code>list.get(0)</code>
*
* @param list a list of nodes
* @param nav the <code>Navigator</code> used to retrieve the namespace
*
* @return the namespace URI of <code>list.get(0)</code>
*
* @throws FunctionCallException if <code>list.get(0)</code> is not a node
*/
public static String evaluate(List list,
Navigator nav) throws FunctionCallException
{
if ( ! list.isEmpty() )
{
Object first = list.get(0);
if ( first instanceof List )
{
return evaluate( (List) first,
nav );
}
else if ( nav.isElement( first ) )
{
return nav.getElementNamespaceUri( first );
}
else if ( nav.isAttribute( first ) )
{
String uri = nav.getAttributeNamespaceUri( first );
if (uri == null) return "";
return uri;
}
else if ( nav.isProcessingInstruction( first ) )
{
return "";
}
else if ( nav.isNamespace( first ) )
{
return "";
}
else if ( nav.isDocument( first ) )
{
return "";
}
else if ( nav.isComment( first ) )
{
return "";
}
else if ( nav.isText( first ) )
{
return "";
}
else {
throw new FunctionCallException(
"The argument to the namespace-uri function must be a node-set");
}
}
return "";
}
}