content: /*
   * $Header$
   * $Revision$
   * $Date$
   *
   * ====================================================================
   *
   * 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/>.
   * 
   * $Id$
   */
  
  package org.jaxen.expr;
  
  import org.jaxen.Context;
  import org.jaxen.UnresolvableException;
  
  class DefaultVariableReferenceExpr extends DefaultExpr implements VariableReferenceExpr
  {
      /**
       * 
       */
      private static final long serialVersionUID = 8832095437149358674L;
      private String prefix;
      private String localName;
  
      DefaultVariableReferenceExpr(String prefix,
                                          String variableName)
      {
          this.prefix       = prefix;
          this.localName = variableName;
      }
  
      public String getPrefix()
      {
          return this.prefix;
      }
  
      public String getVariableName()
      {
          return this.localName;
      }
  
      public String toString()
      {
          return "[(DefaultVariableReferenceExpr): " + getQName() + "]";
      }
      
      private String getQName() {
          if ( "".equals(prefix) )
          {
              return localName;
          }
          return prefix + ":" + localName;
      }
  
      public String getText()
      {
          return "$" + getQName();
      }
  
      public Object evaluate(Context context) throws UnresolvableException
      {
          String prefix = getPrefix();
          String namespaceURI = null;
          // default namespace is not used within XPath expressions
          if (prefix != null && !"".equals(prefix)) {
              namespaceURI = context.translateNamespacePrefixToUri( prefix );
          }
          
          return context.getVariableValue( namespaceURI,
                                           prefix,
                                       localName );
  }
      
  }
  