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 java.io.Serializable;
  import java.util.List;
  
  import org.jaxen.Context;
  import org.jaxen.JaxenException;
  
  
  /**
   * A wrapper around an XPath expression. 
   * 
   */
  public interface XPathExpr extends Serializable
  {
      
      /**
       * Returns the wrapped expression object.
       * 
       * @return the wrapped Expr object
       */
      Expr getRootExpr();
      
      
      /**
       * Changes the wrapped expression object.
       * 
       * @param rootExpr the new expression object to wrap
       */
      void setRootExpr(Expr rootExpr);
      
      /**
       * Returns a String containing the XPath expression.
       * 
       * @return the text form of this XPath expression
       */
      String getText();
      
      /**
       * Simplifies the XPath expression. For example, the expression
       * <code>//para[1 = 1]</code> could be simplified to 
       * <code>//para</code>. In practice, this is usually a noop.
       * Jaxen does not currently perform any simplification.
       */
      void   simplify();
      
      
      /**
       * Evaluates the expression and returns a list cintaing the resulting nodes,
       * or a singleton list containing a <code>Double</code>, <code>String</code>, 
       * or <code>Boolean</code>. 
       * 
       * @param context the context in which to evaluate this expression
       * @return a list
       * @throws JaxenException
       */
      List asList(Context context) throws JaxenException;
  
  }
  