dragon.onlinedb

Interface CollectionReader

All Known Subinterfaces:

ArticleQuery

All Known Implementing Classes:

AbstractQuery, AbstractSearchEngine, AbstractTopicReader, AmazonCatalogQuery, AmazonReviewQuery, ArrayCollectionReader, BasicCollectionReader, CiteULikeTagQuery, EarlyTrecTopicReader, Genomics2004TopicReader, Genomics2005TopicReader, GoogleEngine, PubMedQuery, SimpleCollectionReader, TrecCollectionReader, TrecFileReader

public interface CollectionReader

Interface of Collection Reader which read out articles from a collection one by one

Copyright: Copyright (c) 2005

Company: IST, Drexel University

Version:

1.0

Author:

Davis Zhou

Method Summary

Modifier and Type	Method and Description
void	close() Closes the collection reader and releases all occupied resources.
Article	getArticleByKey(String key) Reads out the article according to its key
ArticleParser	getArticleParser() Gets the article parser of the collection reader
Article	getNextArticle() Collection readers only support forward-only read mode.
void	restart() The collection reader supports forward-only read mode.
void	setArticleParser(ArticleParser parser) Sets the article parse for the collection reader
int	size() The size of the collection.
boolean	supportArticleKeyRetrieval() if the query supports this retrieval mode, one can get articles by calling getArticleByKey method.

Method Detail

getArticleParser

ArticleParser getArticleParser()

Gets the article parser of the collection reader

Returns:

the article parser

setArticleParser

void setArticleParser(ArticleParser parser)

Sets the article parse for the collection reader

Parameters:

parser - the article parser

getNextArticle

Article getNextArticle()

Collection readers only support forward-only read mode. When one call this method after calling restart method or creating the collection reader, it actually return the first article of the collection.

Returns:

the next article

getArticleByKey

Article getArticleByKey(String key)

Reads out the article according to its key

Parameters:

key - the unique entry number of the article

Returns:

an article if exists

supportArticleKeyRetrieval

boolean supportArticleKeyRetrieval()

if the query supports this retrieval mode, one can get articles by calling getArticleByKey method.

Returns:

true if the query support the article retrieval by key.

close

void close()

Closes the collection reader and releases all occupied resources.

restart

void restart()

The collection reader supports forward-only read mode. If one wants to scan the collection for the second time, it is required to call this method. Otherwise when one getNextArticle method, it always return null.

size

int size()

The size of the collection. If the returned size is -1, it means the exact size is unknown.

Returns:

the size of the collection.