/*

  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultLocationPath.java,v 1.29 2006/02/05 21:47:40 elharo Exp $

  * $Revision: 1.29 $

  * $Date: 2006/02/05 21:47:40 $

  *

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

  *

  * 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: DefaultLocationPath.java,v 1.29 2006/02/05 21:47:40 elharo Exp $

  */

 package org.jaxen.expr;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Iterator;

 import java.util.LinkedList;

 import java.util.List;

 import org.jaxen.Context;

 import org.jaxen.ContextSupport;

 import org.jaxen.JaxenException;

 abstract class DefaultLocationPath extends DefaultExpr implements LocationPath

 {

     private List steps;

     /**

      * Create a new empty location path.

      */

     DefaultLocationPath()

     {

         this.steps = new LinkedList();

     }

     public void addStep(Step step)

     {

         getSteps().add(step);

     }

     public List getSteps()

     {

         return this.steps;

     }

     public Expr simplify()

     {

         Iterator stepIter = getSteps().iterator();

         Step eachStep = null;

         while (stepIter.hasNext())

         {

             eachStep = (Step) stepIter.next();

             eachStep.simplify();

         }

         return this;

     }

     public String getText()

     {

         StringBuffer buf = new StringBuffer();

         Iterator stepIter = getSteps().iterator();

         while (stepIter.hasNext())

         {

             buf.append(((Step) stepIter.next()).getText());

             if (stepIter.hasNext())

             {

                 buf.append("/");

             }

         }

         return buf.toString();

     }

     public String toString()

     {

         StringBuffer buf = new StringBuffer();

         Iterator stepIter = getSteps().iterator();

         while (stepIter.hasNext())

         {

             buf.append(stepIter.next().toString());

             if (stepIter.hasNext())

             {

                 buf.append("/");

             }

         }

         return buf.toString();

     }

     public boolean isAbsolute()

     {

         return false;

     }

     public Object evaluate(Context context) throws JaxenException

     {

         List nodeSet = context.getNodeSet();

         List contextNodeSet = new ArrayList(nodeSet);

         ContextSupport support = context.getContextSupport();

         Context stepContext = new Context(support);

         Iterator stepIter = getSteps().iterator();

         while ( stepIter.hasNext() )

         {

             Step eachStep = (Step) stepIter.next();

             stepContext.setNodeSet(contextNodeSet);

             contextNodeSet = eachStep.evaluate(stepContext);

             // now we need to reverse the list if this is a reverse axis

             if (isReverseAxis(eachStep)) {

                 Collections.reverse(contextNodeSet);

             }

         }

         if (getSteps().size() > 1) {

             Collections.sort(contextNodeSet, new NodeComparator(support.getNavigator()));

         }

         return contextNodeSet;

     }

     private boolean isReverseAxis(Step step) {

         int axis = step.getAxis();

         return axis == org.jaxen.saxpath.Axis.PRECEDING

           || axis == org.jaxen.saxpath.Axis.PRECEDING_SIBLING

           || axis == org.jaxen.saxpath.Axis.ANCESTOR

           || axis == org.jaxen.saxpath.Axis.ANCESTOR_OR_SELF;

     }

 }