package hu.origo.lucenetools.iac;
import java.io.IOException;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.IndexSearcher;
import java.util.Hashtable;
/**
 * @author Copied from demo.jsp page
 *
 * Keep a cache of open IndexReader's, so that an index does not
 * have to opened for each query.  The cache re-opens an index when
 * it has changed so that additions and deletions are visible ASAP.
 */
public class IndexReaderCache {

	

   static Hashtable indexCache = new Hashtable();  // name->CachedIndex

   class CachedIndex {                            // a cache entry
     IndexReader reader;                                  // an open reader
     long modified;                               // reader's mod. date

     CachedIndex(String name) throws IOException {
       modified = IndexReader.lastModified(name);  // get mod. date
       reader = IndexReader.open(name);           // open reader
     }
   }

   public IndexReaderCache() {
   }

   public IndexReader getReader(String name) throws IOException {
     CachedIndex index =                                  // look in cache
       (CachedIndex)indexCache.get(name);

       if (index != null &&                       // check up-to-date
          (index.modified == IndexReader.lastModified(name)))
        return index.reader;                      // cache hit
       else {
       	System.out.println("create new");
        index = new CachedIndex(name);            // cache miss
       }


     indexCache.put(name, index);                 // add to cache
     return index.reader;
   }

}