C++ (Cpp) MSet::get_max_attained Examples

Example #1

File: XapianEngine.cpp Project: BackupTheBerlios/pinot-svn

bool XapianEngine::queryDatabase(Xapian::Query &query)
{
	bool bStatus = false;

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, true);
	if (pDatabase == NULL)
	{
		return false;
	}

	// Get the latest revision...
	pDatabase->reopen();
	Xapian::Database *pIndex = pDatabase->readLock();
	if (pIndex != NULL)
	{
		try
		{
			// Start an enquire session on the database
			Xapian::Enquire enquire(*pIndex);

			// Give the query object to the enquire session
			enquire.set_query(query);

			// Get the top results of the query
			Xapian::MSet matches = enquire.get_mset(0, m_maxResultsCount);
			if (matches.empty() == false)
			{
				multimap<Xapian::weight, string> queryTerms;
				vector<string> seedTerms;
				Xapian::weight maxWeight = matches.get_max_attained();

				// Sort query terms by weight
				for (Xapian::TermIterator termIter = query.get_terms_begin();
					termIter != query.get_terms_end(); ++termIter)
				{
					string termName(*termIter);
					Xapian::weight termWeight = maxWeight - matches.get_termweight(termName);

					queryTerms.insert(pair<Xapian::weight, string>(termWeight, termName));
#ifdef DEBUG
					cout << "XapianEngine::queryDatabase: term " << termName
						<< " has weight " << matches.get_termweight(termName) << "/" << maxWeight << endl;
#endif
				}

				for (multimap<Xapian::weight, string>::iterator weightIter = queryTerms.begin();
					weightIter != queryTerms.end(); ++weightIter)
				{
					seedTerms.push_back(weightIter->second);
				}

				// Get the results
#ifdef DEBUG
				cout << "XapianEngine::queryDatabase: " << matches.get_matches_estimated() << "/" << m_maxResultsCount << " results found" << endl;
#endif
				for (Xapian::MSetIterator mIter = matches.begin(); mIter != matches.end(); ++mIter)
				{
					Xapian::docid docId = *mIter;
					Xapian::Document doc(mIter.get_document());
					string record = doc.get_data();

					// Get the title
					string title = StringManip::extractField(record, "caption=", "\n");
#ifdef DEBUG
					cout << "XapianEngine::queryDatabase: found omindex title " << title << endl;
#endif
					// Get the URL
					string url = StringManip::extractField(record, "url=", "\n");
					if (url.empty() == true)
					{
						// Hmmm this shouldn't be empty...
						// Use this instead, even though the document isn't cached in the index
						url = XapianDatabase::buildUrl(m_databaseName, *mIter);
					}
					else
					{
#ifdef DEBUG
						cout << "XapianEngine::queryDatabase: found omindex URL " << url << endl;
#endif
						url = Url::canonicalizeUrl(url);
					}

					// Get the type
					string type = StringManip::extractField(record, "type=", "\n");
					// ...and the language, if available
					string language = StringManip::extractField(record, "language=", "\n");

					// Finally, get a summary
					string summary = StringManip::extractField(record, "sample=", "\n");
					if (summary.empty() == true)
					{
						AbstractGenerator abstractGen(pIndex, 50);

						// Generate an abstract based on the query's terms
						summary = abstractGen.generateAbstract(seedTerms, docId);
					}

					// Add this result
					Result thisResult(url, title, summary, language, (float)mIter.get_percent());
					m_resultsList.push_back(thisResult);
				}
			}

			m_expandTerms.clear();

			// Expand the query ?
			if (m_relevantDocuments.empty() == false)
			{
				Xapian::RSet relevantDocs;
				unsigned int count = 0;

				for (set<unsigned int>::const_iterator docIter = m_relevantDocuments.begin();
					docIter != m_relevantDocuments.end(); ++docIter)
				{
					relevantDocs.add_document(*docIter);
				}

				// Get 10 non-prefixed terms
				Xapian::ESet expandTerms = enquire.get_eset(20, relevantDocs);
				for (Xapian::ESetIterator termIter = expandTerms.begin();
					(termIter != expandTerms.end()) && (count < 10); ++termIter)
				{
					if (isupper((int)((*termIter)[0])) == 0)
					{
						m_expandTerms.insert(*termIter);
						++count;
					}
				}
			}

			bStatus = true;
		}
		catch (const Xapian::Error &error)
		{
			cerr << "XapianEngine::queryDatabase: " << error.get_type() << ": " << error.get_msg() << endl;
		}
	}
	pDatabase->unlock();

	return bStatus;
}