/*

  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultStep.java,v 1.21 2006/02/05 21:47:40 elharo Exp $

  * $Revision: 1.21 $

  * $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: DefaultStep.java,v 1.21 2006/02/05 21:47:40 elharo Exp $

  */

 package org.jaxen.expr;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 import org.jaxen.Context;

 import org.jaxen.ContextSupport;

 import org.jaxen.JaxenException;

 import org.jaxen.UnsupportedAxisException;

 import org.jaxen.expr.iter.IterableAxis;

 import org.jaxen.saxpath.Axis;

 /**

  * @deprecated this class will become non-public in the future;

  *     use the interface instead

  */

 public abstract class DefaultStep implements Step

 {

     private IterableAxis axis;

     private PredicateSet predicates;

     public DefaultStep(IterableAxis axis, PredicateSet predicates)

     {

         this.axis = axis;

         this.predicates = predicates;

     }

     public void addPredicate(Predicate predicate)

     {

         this.predicates.addPredicate(predicate);

     }

     public List getPredicates()

     {

         return this.predicates.getPredicates();

     }

     public PredicateSet getPredicateSet()

     {

         return this.predicates;

     }

     public int getAxis()

     {

         return this.axis.value();

     }

     public IterableAxis getIterableAxis()

     {

         return this.axis;

     }

     public String getAxisName()

     {

         return Axis.lookup(getAxis());

     }

     public String getText()

     {

         return this.predicates.getText();

     }

     public String toString()

     {

         return getIterableAxis() + " " + super.toString();

     }

     public void simplify()

     {

         this.predicates.simplify();

     }

     public Iterator axisIterator(Object contextNode, ContextSupport support)

         throws UnsupportedAxisException

     {

         return getIterableAxis().iterator(contextNode, support);

     }

     public List evaluate(final Context context) throws JaxenException

     {

         final List contextNodeSet  = context.getNodeSet();

         final IdentitySet unique = new IdentitySet();

         final int contextSize = contextNodeSet.size();

         // ???? try linked lists instead?

         // ???? initial size for these?

         final ArrayList interimSet = new ArrayList();

         final ArrayList newNodeSet = new ArrayList();

         final ContextSupport support = context.getContextSupport();

         // ???? use iterator instead

         for ( int i = 0 ; i < contextSize ; ++i )

         {

             Object eachContextNode = contextNodeSet.get( i );

                 /* See jaxen-106. Might be able to optimize this by doing

                  * specific matching for individual axes. For instance on namespace axis

                  * we should only get namespace nodes and on attribute axes we only get 

                  * attribute nodes. Self and parent axes have single members.

                  * Children, descendant, ancestor, and sibling axes never 

                  * see any attributes or namespaces

                  */

             Iterator axisNodeIter = axis.iterator(eachContextNode, support);

             while ( axisNodeIter.hasNext() )

             {

                 Object eachAxisNode = axisNodeIter.next();

                 if ( ! unique.contains( eachAxisNode ) )

                 {

                     if ( matches( eachAxisNode, support ) )

                     {

                         unique.add( eachAxisNode );

                         interimSet.add( eachAxisNode );

                     }

                 }

             }

             newNodeSet.addAll(getPredicateSet().evaluatePredicates(

                               interimSet, support ));

             interimSet.clear();

         }

         return newNodeSet;

     }

 }