// BSD License (http://www.galagosearch.org/license)

 package org.galagosearch.core.retrieval.structured;

 import java.io.IOException;

 import java.util.ArrayList;

 import org.galagosearch.tupleflow.Parameters;

 import org.galagosearch.tupleflow.Utility;

 /**

  *

  * @author trevor

  */

 public class OrderedWindowIterator extends ExtentConjunctionIterator {

     int width;

     /** Creates a new instance of UnorderedWindowIterator */

     public OrderedWindowIterator(Parameters parameters, ExtentIterator[] iterators) throws IOException {

         super(iterators);

         this.width = (int) parameters.getAsDefault("width", -1);

         findDocument();

     }

     public void loadExtents() {

         ExtentArrayIterator[] iterators;

         iterators = new ExtentArrayIterator[extentIterators.length];

         for (int i = 0; i < extentIterators.length; i++) {

             iterators[i] = new ExtentArrayIterator(

                     extentIterators[i].extents());

         }

         boolean notDone = true;

         while (notDone) {

             // find the start of the first word

             boolean invalid = false;

             int begin = iterators[0].current().begin;

             // loop over all the rest of the words

             for (int i = 1; i < iterators.length; i++) {

                 int end = iterators[i - 1].current().end;

                 // try to move this iterator so that it's past the end of the previous word

                 while (end > iterators[i].current().begin) {

                     notDone = iterators[i].next();

                     // if there are no more occurrences of this word,

                     // no more ordered windows are possible

                     if (!notDone) {

                         return;

                     }

                 }

                 if (iterators[i].current().begin - end >= width) {

                     invalid = true;

                     break;

                 }

             }

             int end = iterators[iterators.length - 1].current().end;

             // if it's a match, record it

             if (!invalid) {

                 extents.add(document, begin, end);

             }

             notDone = iterators[0].next();

         }

     }

 }