/*
    * $Header$
    * $Revision$
    * $Date$
    *
    * ====================================================================
    *
    * 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.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import org.jaxen.Context;
  import org.jaxen.ContextSupport;
  import org.jaxen.JaxenException;
  import org.jaxen.function.BooleanFunction;
  
  /**
   * <p>
   * Represents the collection of predicates that follow the node-test in a
   * location path. 
   * </p>
   * 
   * <p>
   * There is no rule that the same predicate may not 
   * appear twice in an XPath expression, nor does this class enforce any such rule.
   * This is implemented more as a list than a set. However, adding the same predicate 
   * twice should have no effect on the final result other than slowing it down.
   * </p>
   */
  public class PredicateSet implements Serializable
  {
  
      private static final long serialVersionUID = -7166491740228977853L;
      
      private List<Predicate> predicates;
  
      /**
       * Create a new empty predicate set.
       */
      public PredicateSet()
      {
          this.predicates = new ArrayList<Predicate>();
      }
  
      /**
       * Add a predicate to the set.
       * 
       * @param predicate the predicate to be inserted
       */
      public void addPredicate(Predicate predicate)
      {
          this.predicates.add( predicate );
      }
  
     /**
      * Returns the list containing the predicates.
      * This list is live, not a copy.
      * 
      * @return a live list of predicates
      */
     public List getPredicates()
     {
         return this.predicates;
     }
 
     /**
      * Simplify each of the predicates in the list.
      */
     public void simplify()
     {
         Iterator<Predicate>  predIter = this.predicates.iterator();
         Predicate eachPred = null;
 
         while ( predIter.hasNext() )
         {
             eachPred = predIter.next();
             eachPred.simplify();
         }
     }
 
     /**
      * Returns the XPath string containing each of the predicates.
      * 
      * @return the XPath string containing each of the predicates
      */
     public String getText()
     {
         StringBuffer buf = new StringBuffer();
 
         Iterator<Predicate>  predIter = this.predicates.iterator();
         Predicate eachPred = null;
 
         while ( predIter.hasNext() )
         {
             eachPred = (Predicate) predIter.next();
             buf.append( eachPred.getText() );
         }
 
         return buf.toString();
     }
 
     /**
      * <p>Returns true if any of the supplied nodes satisfy 
      * all the predicates in the set. Returns false if none of the supplied
      * nodes matches all the predicates in the set. Returns false if the 
      * node-set is empty.</p>
      * 
      * @param contextNodeSet the nodes to test against these predicates
      * @param support ????
      * @return true if any node in the contextNodeSet matches all the predicates
      * @throws JaxenException
      */
     protected boolean evaluateAsBoolean(List contextNodeSet,
                                       ContextSupport support) throws JaxenException
     {
         return anyMatchingNode( contextNodeSet, support );
     }
 
    private boolean anyMatchingNode(List contextNodeSet, ContextSupport support)
      throws JaxenException {
         // Easy way out (necessary)
         if (predicates.isEmpty()) {
             return false;
         }
         Iterator<Predicate> predIter = predicates.iterator();
 
         // initial list to filter
         List nodes2Filter = contextNodeSet;
         // apply all predicates
         while(predIter.hasNext()) {
             final int nodes2FilterSize = nodes2Filter.size();
             // Set up a dummy context with a list to hold each node
             Context predContext = new Context(support);
             List<Object> tempList = new ArrayList<Object>(1);
             predContext.setNodeSet(tempList);
             // loop through the current nodes to filter and add to the
             // filtered nodes list if the predicate succeeds
             for (int i = 0; i < nodes2FilterSize; ++i) {
                 Object contextNode = nodes2Filter.get(i);
                 tempList.clear();
                 tempList.add(contextNode);
                 predContext.setNodeSet(tempList);
                 // ????
                 predContext.setPosition(i + 1);
                 predContext.setSize(nodes2FilterSize);
                 Object predResult = ((Predicate)predIter.next()).evaluate(predContext);
                 if (predResult instanceof Number) {
                     // Here we assume nodes are in forward or reverse order
                     // as appropriate for axis
                     int proximity = ((Number) predResult).intValue();
                     if (proximity == (i + 1)) {
                         return true;
                     }
                 }
                 else {
                     Boolean includes =
                         BooleanFunction.evaluate(predResult,
                                                 predContext.getNavigator());
                     if (includes.booleanValue()) {
                         return true;
                     }
                 }
             }
         }
         
         return false;
     }
    
     
     
     
    /**
     * <p>Returns all of the supplied nodes that satisfy 
     * all the predicates in the set. </p>
     * 
     * @param contextNodeSet the nodes to test against these predicates
     * @param support ????
     * @return all the nodes that match each of the predicates
     * @throws JaxenException
     */
    protected List evaluatePredicates(List contextNodeSet, ContextSupport support)
             throws JaxenException {
         // Easy way out (necessary)
         if (predicates.size() == 0) {
             return contextNodeSet;
         }
         Iterator<Predicate> predIter = predicates.iterator();
 
         // initial list to filter
         List nodes2Filter = contextNodeSet;
         // apply all predicates
         while(predIter.hasNext()) {
             nodes2Filter =
                 applyPredicate((Predicate)predIter.next(), nodes2Filter, support);
         }
         
         return nodes2Filter;
     }
    
     public List applyPredicate(Predicate predicate, List nodes2Filter, ContextSupport support)
             throws JaxenException {
         final int nodes2FilterSize = nodes2Filter.size();
         List<Object> filteredNodes = new ArrayList<Object>(nodes2FilterSize);
         // Set up a dummy context with a list to hold each node
         Context predContext = new Context(support);
         List<Object> tempList = new ArrayList<Object>(1);
         predContext.setNodeSet(tempList);
         // loop through the current nodes to filter and add to the
         // filtered nodes list if the predicate succeeds
         for (int i = 0; i < nodes2FilterSize; ++i) {
             Object contextNode = nodes2Filter.get(i);
             tempList.clear();
             tempList.add(contextNode);
             predContext.setNodeSet(tempList);
             // ????
             predContext.setPosition(i + 1);
             predContext.setSize(nodes2FilterSize);
             Object predResult = predicate.evaluate(predContext);
             if (predResult instanceof Number) {
                 // Here we assume nodes are in forward or reverse order
                 // as appropriate for axis
                 int proximity = ((Number) predResult).intValue();
                 if (proximity == (i + 1)) {
                     filteredNodes.add(contextNode);
                 }
             }
             else {
                 Boolean includes =
                     BooleanFunction.evaluate(predResult,
                                             predContext.getNavigator());
                 if (includes.booleanValue()) {
                     filteredNodes.add(contextNode);
                 }
             }
         }
         return filteredNodes;
     }
     
 }