cdmlib-services/src/main/java/eu/etaxonomy/cdm/api/service/search/DocIdBitSetPrinter.java

   1 /**
   2 * Copyright (C) 2013 EDIT
   3 * European Distributed Institute of Taxonomy
   4 * http://www.e-taxonomy.eu
   5 *
   6 * The contents of this file are subject to the Mozilla Public License Version 1.1
   7 * See LICENSE.TXT at the top of this package for the full license terms.
   8 */
   9 package eu.etaxonomy.cdm.api.service.search;
  10
  11 import java.io.IOException;
  12
  13 import org.apache.log4j.Logger;
  14 import org.apache.lucene.search.DocIdSet;
  15 import org.apache.lucene.search.DocIdSetIterator;
  16
  17 /**
  18  * Helper class, for printing out information on {@link DocIdSet}s
  19  *
  20  * @author a.kohlbecker
  21  * @date Sep 24, 2013
  22  *
  23  */
  24 public class DocIdBitSetPrinter {
  25
  26     public static final Logger logger = Logger.getLogger(DocIdBitSetPrinter.class);
  27
  28     public static String docsAsString(DocIdSet docset, int maxdocs){
  29
  30         StringBuilder sb = new StringBuilder();
  31         try {
  32             DocIdSetIterator it = docset.iterator();
  33             int i = 0;
  34             while(i < maxdocs){
  35                 int docId = it.nextDoc();
  36                 if(docId == DocIdSetIterator.NO_MORE_DOCS){
  37                     break;
  38                 }
  39                 sb.append(docId).append(" ");
  40             }
  41         } catch (IOException e) {
  42             logger.error("Error while reding doc ids from DocIdSet", e);
  43         }
  44
  45         return sb.toString();
  46     }
  47
  48 }