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

 package org.galagosearch.core.parse;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.util.HashMap;

 import org.galagosearch.core.index.IndexReader;

 import org.galagosearch.tupleflow.DataStream;

 import org.galagosearch.tupleflow.VByteInput;

 /**

  *

  * @author trevor

  */

 public class DocumentIndexReader {

     IndexReader reader;

     public DocumentIndexReader(String fileName) throws FileNotFoundException, IOException {

         reader = new IndexReader(fileName);

     }

     public DocumentIndexReader(IndexReader reader) {

         this.reader = reader;

     }

     public void close() throws IOException {

         reader.close();

     }

     public Iterator getIterator() throws IOException {

         return new Iterator(reader.getIterator());

     }

     public Document getDocument(String key) throws IOException {

         IndexReader.Iterator iterator = reader.getIterator(key);

         if (iterator == null) return null;

         return new Iterator(iterator).getDocument();

     }

     public class Iterator {

         IndexReader.Iterator iterator;

         Iterator(IndexReader.Iterator iterator) throws IOException {

             this.iterator = iterator;

         }

         public void skipTo(byte[] key) throws IOException {

             iterator.skipTo(key);

         }

         public String getKey() {

             return iterator.getKey();

         }

         public boolean isDone() {

             return iterator.isDone();

         }

         public Document getDocument() throws IOException {

             String key = iterator.getKey();

             DataStream stream = iterator.getValueStream();

             return decodeDocument(key, stream);

         }

         public boolean nextDocument() throws IOException {

             return iterator.nextKey();

         }

         Document decodeDocument(String key, DataStream stream) throws IOException {

             VByteInput input = new VByteInput(stream);

             Document document = new Document();

             // The first string is the document text, followed by

             // key/value metadata pairs.

             document.identifier = key;

             document.text = input.readString();

             document.metadata = new HashMap<String, String>();

             while (!stream.isDone()) {

                 String mapKey = input.readString();

                 String mapValue = input.readString();

                 document.metadata.put(mapKey, mapValue);

             }

             return document;

         }

     }

 }