/*

  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/XPathFunctionContext.java,v 1.29 2006/11/08 13:59:38 elharo Exp $

  * $Revision: 1.29 $

  * $Date: 2006/11/08 13:59:38 $

  *

  * ====================================================================

  *

  * 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: XPathFunctionContext.java,v 1.29 2006/11/08 13:59:38 elharo Exp $

  */

 package org.jaxen;

 import org.jaxen.function.BooleanFunction;

 import org.jaxen.function.CeilingFunction;

 import org.jaxen.function.ConcatFunction;

 import org.jaxen.function.ContainsFunction;

 import org.jaxen.function.CountFunction;

 import org.jaxen.function.FalseFunction;

 import org.jaxen.function.FloorFunction;

 import org.jaxen.function.IdFunction;

 import org.jaxen.function.LangFunction;

 import org.jaxen.function.LastFunction;

 import org.jaxen.function.LocalNameFunction;

 import org.jaxen.function.NameFunction;

 import org.jaxen.function.NamespaceUriFunction;

 import org.jaxen.function.NormalizeSpaceFunction;

 import org.jaxen.function.NotFunction;

 import org.jaxen.function.NumberFunction;

 import org.jaxen.function.PositionFunction;

 import org.jaxen.function.RoundFunction;

 import org.jaxen.function.StartsWithFunction;

 import org.jaxen.function.StringFunction;

 import org.jaxen.function.StringLengthFunction;

 import org.jaxen.function.SubstringAfterFunction;

 import org.jaxen.function.SubstringBeforeFunction;

 import org.jaxen.function.SubstringFunction;

 import org.jaxen.function.SumFunction;

 import org.jaxen.function.TranslateFunction;

 import org.jaxen.function.TrueFunction;

 import org.jaxen.function.ext.EndsWithFunction;

 import org.jaxen.function.ext.EvaluateFunction;

 import org.jaxen.function.ext.LowerFunction;

 import org.jaxen.function.ext.UpperFunction;

 import org.jaxen.function.xslt.DocumentFunction;

 /** A <code>FunctionContext</code> implementing the core XPath

  *  function library, plus Jaxen extensions.

  *

  *  <p>

  *  The core XPath function library is provided through this

  *  implementation of <code>FunctionContext</code>.  Additionally,

  *  extension functions have been provided, as enumerated below.

  *  </p>

  *

  *  <p>

  *  This class is re-entrant and thread-safe.  If using the

  *  default instance, it is inadvisable to call 

  *  {@link #registerFunction(String, String, Function)}

  *  as that will extend the global function context, affecting other

  *  users. 

  *  </p>

  *

  *  <p>

  *  Extension functions:

  *  </p>

  *

  *  <ul>

  *     <li>evaluate(..)</li>

  *     <li>upper-case(..)</li>

  *     <li>lower-case(..)</li>

  *     <li>ends-with(..)</li>

  *  </ul>

  *

  *  @see FunctionContext

  *  @see org.jaxen.function

  *  @see org.jaxen.function.xslt

  *  @see org.jaxen.function.ext

  *

  *  @author <a href="mailto:bob@werken.com">bob mcwhirter</a>

  */

 public class XPathFunctionContext extends SimpleFunctionContext

 {

     private static XPathFunctionContext instance = new XPathFunctionContext();

     /** Retrieve the default function context

      *

      *  @return the default function context

      */

     public static FunctionContext getInstance()

     {

         return instance;

     }

     /** Create a new XPath function context.

      *  All core XPath and Jaxen extension functions are registered.

      */

     public XPathFunctionContext()

     {

         this(true);

     }

     /** Create a new XPath function context.

      *  All core XPath functions are registered.

      *  

      * @param includeExtensionFunctions if true extension functions are included;

      *     if false, they aren't

      */

     public XPathFunctionContext(boolean includeExtensionFunctions)

     {

         registerXPathFunctions();

         if (includeExtensionFunctions) {

             registerXSLTFunctions();

             registerExtensionFunctions();

         }

     }

     private void registerXPathFunctions() {

         registerFunction( null,  // namespace URI

                           "boolean",

                           new BooleanFunction() );

         registerFunction( null,  // namespace URI

                           "ceiling",

                           new CeilingFunction() );

         registerFunction( null,  // namespace URI

                           "concat",

                           new ConcatFunction() );

         registerFunction( null,  // namespace URI

                           "contains",

                           new ContainsFunction() );

         registerFunction( null,  // namespace URI

                           "count",

                           new CountFunction() );

         registerFunction( null,  // namespace URI

                           "false",

                           new FalseFunction() );

         registerFunction( null,  // namespace URI

                           "floor",

                           new FloorFunction() );

         registerFunction( null,  // namespace URI

                           "id",

                           new IdFunction() );

         registerFunction( null,  // namespace URI

                           "lang",

                           new LangFunction() );

         registerFunction( null,  // namespace URI

                           "last",

                           new LastFunction() );

         registerFunction( null,  // namespace URI

                           "local-name",

                           new LocalNameFunction() );

         registerFunction( null,  // namespace URI

                           "name",

                           new NameFunction() );

         registerFunction( null,  // namespace URI

                           "namespace-uri",

                           new NamespaceUriFunction() );

         registerFunction( null,  // namespace URI

                           "normalize-space",

                           new NormalizeSpaceFunction() );

         registerFunction( null,  // namespace URI

                           "not",

                           new NotFunction() );

         registerFunction( null,  // namespace URI

                           "number",

                           new NumberFunction() );

         registerFunction( null,  // namespace URI

                           "position",

                           new PositionFunction() );

         registerFunction( null,  // namespace URI

                           "round",

                           new RoundFunction() );

         registerFunction( null,  // namespace URI

                           "starts-with",

                           new StartsWithFunction() );

         registerFunction( null,  // namespace URI

                           "string",

                           new StringFunction() );

         registerFunction( null,  // namespace URI

                           "string-length",

                           new StringLengthFunction() );

         registerFunction( null,  // namespace URI

                           "substring-after",

                           new SubstringAfterFunction() );

         registerFunction( null,  // namespace URI

                           "substring-before",

                           new SubstringBeforeFunction() );

         registerFunction( null,  // namespace URI

                           "substring",

                           new SubstringFunction() );

         registerFunction( null,  // namespace URI

                           "sum",

                           new SumFunction() );

         registerFunction( null,  // namespace URI

                           "true",

                           new TrueFunction() );

         registerFunction( null,  // namespace URI

                           "translate",

                           new TranslateFunction() );

     }

     private void registerXSLTFunctions() {

         // extension functions defined in XSLT

         registerFunction( null,  // namespace URI

                           "document",

                           new DocumentFunction() );

     }

     private void registerExtensionFunctions() {

         // extension functions should go into a namespace, but which one?

         // for now, keep them in default namespace to not break any code

         registerFunction( null,  // namespace URI

                           "evaluate",

                           new EvaluateFunction() );

         registerFunction( null,  // namespace URI

                           "lower-case",

                           new LowerFunction() );

         registerFunction( null,  // namespace URI

                           "upper-case",

                           new UpperFunction() );

         registerFunction( null,  // namespace URI

                           "ends-with",

                           new EndsWithFunction() );

     }

 }