/*
* $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/SimpleFunctionContext.java,v 1.14 2006/02/05 21:47:41 elharo Exp $
* $Revision: 1.14 $
* $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: SimpleFunctionContext.java,v 1.14 2006/02/05 21:47:41 elharo Exp $
*/
package org.orbeon.jaxen;
import java.util.HashMap;
/** Simple default implementation of <code>FunctionContext</code>.
*
* <p>
* This is a simple table-based key-lookup implementation
* for <code>FunctionContext</code> which can be programmatically
* extended by registering additional functions.
* </p>
*
* @see XPathFunctionContext
*
* @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
*/
public class SimpleFunctionContext implements FunctionContext
{
/** Table of functions. */
private HashMap functions;
/**
* <p>
* Construct an empty function context.
* </p>
*/
public SimpleFunctionContext()
{
this.functions = new HashMap();
}
/** Register a new function.
*
* <p>
* By registering a new function, any XPath expression
* that utilizes this <code>FunctionContext</code> may
* refer to and use the new function.
* </p>
*
* <p>
* Functions may exist either in a namespace or not.
* Namespace prefix-to-URI resolution is the responsibility
* of a {@link NamespaceContext}. Within this <code>FunctionContext</code>
* functions are only referenced using the URI, <strong>not</strong>
* the prefix.
* </p>
*
* <p>
* The namespace URI of a function may be <code>null</code>
* to indicate that it exists without a namespace.
* </p>
*
* @param namespaceURI the namespace URI of the function to
* be registered with this context
* @param localName the non-prefixed local portion of the
* function to be registered with this context
* @param function a {@link Function} implementation object
* to be used when evaluating the function
*/
public void registerFunction(String namespaceURI,
String localName,
Function function )
{
this.functions.put( new QualifiedName(namespaceURI, localName),
function );
}
public Function getFunction(String namespaceURI,
String prefix,
String localName )
throws UnresolvableException
{
QualifiedName key = new QualifiedName( namespaceURI, localName );
if ( this.functions.containsKey(key) ) {
return (Function) this.functions.get( key );
}
else {
throw new UnresolvableException( "No Such Function " + key.getClarkForm() );
}
}
}