edu.umd.cloud9.collection
Interface DocnoMapping

All Known Implementing Classes:

Aquaint2DocnoMapping, ClueWarcDocnoMapping, Gov2DocnoMapping, MedlineDocnoMapping, TextDocnoMapping, TrecDocnoMapping, WikipediaDocnoMapping, Wt10gDocnoMapping

public interface DocnoMapping

Interface for an object that maintains a bidirectional mapping between docids and docnos. A docid is a globally-unique String identifier for a document in the collection. For many types of information retrieval algorithms, documents in the collection must be sequentially numbered; thus, each document in the collection must be assigned a unique integer identifier, which is its docno. Typically, the docid/docno mappings are stored in a mappings file, which is loaded into memory by concrete objects implementing this interface.

Unless there are compelling reasons otherwise, it is preferable to start numbering docnos from one instead of zero. This is because zero cannot be represented in many common compression schemes that are used in information retrieval (e.g., Golomb codes).

Author:

Jimmy Lin

Method Summary

String	getDocid(int docno) Returns the docid for a particular docno.
int	getDocno(String docid) Returns the docno for a particular docid.
void	loadMapping(Path path, FileSystem fs) Loads a mapping file containing the docid/docno mappings.

Method Detail

getDocno

int getDocno(String docid)

Returns the docno for a particular docid.

Parameters:

docid - the docid

Returns:

the docno for the docid

getDocid

String getDocid(int docno)

Returns the docid for a particular docno.

Parameters:

docno - the docno

Returns:

the docid for the docno

loadMapping

void loadMapping(Path path,
                 FileSystem fs)
                 throws IOException

Loads a mapping file containing the docid/docno mappings.

Parameters:

path - path to the mappings file

fs - reference to the FileSystem

Throws:

IOException