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.util.Iterator;
  import java.util.List;
  
  import org.jaxen.Context;
  import org.jaxen.ContextSupport;
  import org.jaxen.JaxenException;
  import org.jaxen.UnsupportedAxisException;
  
  /**
   * <p>Represents a location step in a LocationPath. The node-set selected by 
   * the location step is the node-set that results from generating an initial 
   * node-set from the axis and node-test, and then filtering that node-set by 
   * each of the predicates in turn.</p>
   * 
   * <p>
   * The initial node-set consists of the nodes having the relationship to the 
   * context node specified by the axis, and having the node type and expanded-name 
   * specified by the node test.</p>
   */
  public interface Step extends Predicated
  {
  
      /**
       * Performs the node-test part of evaluating the step for the given node
       * (which must be on the axis).
       * 
       * @return true if the node matches this step; false if it doesn't
       */    
      boolean matches(Object node,
                      ContextSupport contextSupport) throws JaxenException;
  
      /**
       * Returns a <code>String</code> containing the XPath expression.
       * 
       * @return the text form of this step
       */
      String getText();
  
      /**
       * Simplifies the XPath step. In practice, this is usually a noop.
       * Jaxen does not currently perform any simplification.
       */
      void simplify();
  
      /**
       * Get an identifier for the current axis.
       * 
       * @return the axis identifier
       * @see org.jaxen.saxpath.Axis
       */
      public int getAxis();
  
      /**
       * Get an Iterator for the current axis starting in the given contextNode.
       * 
       * @param contextNode the node from which to follow this step
       * @param support the remaining context for the traversal
       * @return an iterator over the nodes along the axis
       * @throws UnsupportedAxisException if the navigator does not support this step's axis
       * 
       */
      Iterator axisIterator(Object contextNode,
                            ContextSupport support) throws UnsupportedAxisException;
      
  
      /**
       * For each node in the given context calls matches() for every node on the
       * axis, then filters the result by each of the predicates.
       * 
       * @return a list of matching nodes
       */
      List evaluate(Context context) throws JaxenException;
  
  }
  
  