/**
* Given a unique key such as a URL, locate the document
* and return its term frequency vector.
*
* return null if the key is not found.
*
* When a document is located its docnum is used to retrieve the
* term frequency vector
*
* @param url
* @return
* @throws IOException
*/
public TermFreqVector getTermVectors(String url) throws IOException
{
//Locate the matching document
LuceneIndex li = LuceneIndexHolder.getLuceneIndex();
int docnum = li.locateIndexedUrlDocNumber(url);
//Document not found
if (docnum == -1)
{
return null;
}
//Document found
IndexReader reader = li.getReader();
//Log.log("Index has " + reader.numDocs() + " documents.");
TermFreqVector tfv = reader.getTermFreqVector(docnum,"content");
return tfv;
}