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

 package org.galagosearch.core.retrieval;

 import java.io.IOException;

 import org.galagosearch.core.retrieval.query.Node;

 import org.galagosearch.core.retrieval.structured.StructuredRetrieval;

 /**

  * <p>This is a base class for all kinds of retrieval classes.  Historically this was

  * used to support binned indexes in addition to structured indexes.</p>

  *

  * @author trevor

  */

 public abstract class Retrieval {

     public abstract String getDocumentName(int document) throws IOException;

     /**

      * Transforms the query into a more complete representation that can

      * be directly executed.

      */

     public abstract Node transformQuery(Node query) throws Exception;

     public abstract ScoredDocument[] runQuery(Node query, int requested) throws Exception;

     public abstract void close() throws IOException;

     static public Retrieval instance(String indexPath) throws IOException {

         return new StructuredRetrieval(indexPath);

     }

 }