poco/MongoDB/include/Poco/MongoDB/OpMsgCursor.h

//
// OpMsgCursor.h
//
// Library: MongoDB
// Package: MongoDB
// Module:  OpMsgCursor
//
// Definition of the OpMsgCursor class.
//
// Copyright (c) 2012, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef MongoDB_OpMsgCursor_INCLUDED
#define MongoDB_OpMsgCursor_INCLUDED


#include "Poco/MongoDB/MongoDB.h"
#include "Poco/MongoDB/Connection.h"
#include "Poco/MongoDB/OpMsgMessage.h"

namespace Poco {
namespace MongoDB {


class MongoDB_API OpMsgCursor: public Document
	/// OpMsgCursor is an helper class for querying multiple documents using OpMsgMessage.
{
public:
	OpMsgCursor(const std::string& dbname, const std::string& collectionName);
		/// Creates a OpMsgCursor for the given database and collection.

	virtual ~OpMsgCursor();
		/// Destroys the OpMsgCursor.

	void setEmptyFirstBatch(bool empty);
		/// Empty first batch is used to get error response faster with little server processing

	bool emptyFirstBatch() const;

	void setBatchSize(Int32 batchSize);
		/// Set non-default batch size

	Int32 batchSize() const;
		/// Current batch size (zero or negative number indicates default batch size)

	Int64 cursorID() const;

	OpMsgMessage& next(Connection& connection);
		/// Tries to get the next documents. As long as response message has a
		/// cursor ID next can be called to retrieve the next bunch of documents.
		///
		/// The cursor must be killed (see kill()) when not all documents are needed.

	OpMsgMessage& query();
		/// Returns the associated query.

	void kill(Connection& connection);
		/// Kills the cursor and reset it so that it can be reused.

private:
	OpMsgMessage    _query;
	OpMsgMessage 	_response;

	bool			_emptyFirstBatch { false };
	Int32			_batchSize { -1 };
		/// Batch size used in the cursor. Zero or negative value means that default shall be used.

	Int64			_cursorID { 0 };
};


//
// inlines
//
inline OpMsgMessage& OpMsgCursor::query()
{
	return _query;
}

inline Int64 OpMsgCursor::cursorID() const
{
	return _cursorID;
}


} } // namespace Poco::MongoDB


#endif // MongoDB_OpMsgCursor_INCLUDED