/*

  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/PredicateSet.java,v 1.23 2006/11/13 22:38:17 elharo Exp $

  * $Revision: 1.23 $

  * $Date: 2006/11/13 22:38:17 $

  *

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

  *

  * 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: PredicateSet.java,v 1.23 2006/11/13 22:38:17 elharo Exp $

  */

 package org.jaxen.expr;

 import java.io.Serializable;

 import java.util.ArrayList;

 import java.util.Collections;

 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 swme 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 predicates;

     /**

      * Create a new empty predicate set.

      */

     public PredicateSet()

     {

         this.predicates = Collections.EMPTY_LIST;

     }

     /**

      * Add a predicate to the set.

      * 

      * @param predicate the predicate to be inserted

      */

     public void addPredicate(Predicate predicate)

     {

         if ( this.predicates == Collections.EMPTY_LIST )

         {

             this.predicates = new ArrayList();

         }

         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  predIter = this.predicates.iterator();

         Predicate eachPred = null;

         while ( predIter.hasNext() )

         {

             eachPred = (Predicate) 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  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.size() == 0) {

             return false;

         }

         Iterator 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 tempList = new ArrayList(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 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 filteredNodes = new ArrayList(nodes2FilterSize);

         // Set up a dummy context with a list to hold each node

         Context predContext = new Context(support);

         List tempList = new ArrayList(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;

     }

 }