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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/FunctionContext.java,v 1.9 2005/06/28 13:44:44 elharo Exp $
    3    * $Revision: 1.9 $
    4    * $Date: 2005/06/28 13:44:44 $
    5    *
    6    * ====================================================================
    7    *
    8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
    9    * All rights reserved.
    10   *
    11   * Redistribution and use in source and binary forms, with or without
    12   * modification, are permitted provided that the following conditions
    13   * are met:
    14   *
    15   * 1. Redistributions of source code must retain the above copyright
    16   *    notice, this list of conditions, and the following disclaimer.
    17   *
    18   * 2. Redistributions in binary form must reproduce the above copyright
    19   *    notice, this list of conditions, and the disclaimer that follows
    20   *    these conditions in the documentation and/or other materials
    21   *    provided with the distribution.
    22   *
    23   * 3. The name "Jaxen" must not be used to endorse or promote products
    24   *    derived from this software without prior written permission.  For
    25   *    written permission, please contact license@jaxen.org.
    26   *
    27   * 4. Products derived from this software may not be called "Jaxen", nor
    28   *    may "Jaxen" appear in their name, without prior written permission
    29   *    from the Jaxen Project Management (pm@jaxen.org).
    30   *
    31   * In addition, we request (but do not require) that you include in the
    32   * end-user documentation provided with the redistribution and/or in the
    33   * software itself an acknowledgement equivalent to the following:
    34   *     "This product includes software developed by the
    35   *      Jaxen Project <http://www.jaxen.org/>."
    36   * Alternatively, the acknowledgment may be graphical using the logos
    37   * available at http://www.jaxen.org/
    38   *
    39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
    43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    50   * SUCH DAMAGE.
    51   *
    52   * ====================================================================
    53   * This software consists of voluntary contributions made by many
    54   * individuals on behalf of the Jaxen Project and was originally
    55   * created by bob mcwhirter <bob@werken.com> and
    56   * James Strachan <jstrachan@apache.org>.  For more information on the
    57   * Jaxen Project, please see <http://www.jaxen.org/>.
    58   *
    59   * $Id: FunctionContext.java,v 1.9 2005/06/28 13:44:44 elharo Exp $
    60   */
    61
    62
    63  package org.jaxen;
    64
    65  /*** Implemented by classes that know how to resolve XPath function names and
    66   *  namespaces to implementations of these functions.
    67   *
    68   *  <p>
    69   *  By using a custom <code>FunctionContext</code>, new or different
    70   *  functions may be installed and available to XPath expression writers.
    71   *  </p>
    72   *
    73   *  @see XPathFunctionContext
    74   *
    75   *  @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
    76   */
    77  public interface FunctionContext
    78  {
    79      /*** An implementation should return a <code>Function</code> implementation object
    80       *  based on the namespace URI and local name of the function-call
    81       *  expression.
    82       *
    83       *  <p>
    84       *  It must not use the prefix parameter to select an implementation,
    85       *  because a prefix could be bound to any namespace; the prefix parameter
    86       *  could be used in debugging output or other generated information.
    87       *  The prefix may otherwise be completely ignored.
    88       *  </p>
    89       *
    90       *  @param namespaceURI  the namespace URI to which the prefix parameter
    91       *                       is bound in the XPath expression. If the function
    92       *                       call expression had no prefix, the namespace URI
    93       *                       is <code>null</code>.
    94       *  @param prefix        the prefix that was used in the function call
    95       *                       expression
    96       *  @param localName     the local name of the function-call expression.
    97       *                       If there is no prefix, then this is the whole
    98       *                       name of the function.
    99       *
    100      *  @return  a Function implementation object.
    101      *  @throws UnresolvableException  when the function cannot be resolved
    102      */
    103     Function getFunction( String namespaceURI,
    104                           String prefix,
    105                           String localName ) throws UnresolvableException;
    106 }