204 lines
4.4 KiB
C++
204 lines
4.4 KiB
C++
/*
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----
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This file is part of SECONDO.
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Copyright (C) 2014, University in Hagen, Faculty of Mathematics and
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Computer Science, Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published
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by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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Jan Kristof Nidzwetzki
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//paragraph [1] Title: [{\Large \bf \begin{center}] [\end{center}}]
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//paragraph [10] Footnote: [{\footnote{] [}}]
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//[TOC] [\tableofcontents]
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[TOC]
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0 Overview
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This file contains a connection pool for cassandra connections. If
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you request a connection the first time, the connection will be
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established. If you request a connection a second time, the
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already established connection will be returned.
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The pool holds one connection per initial cassandra server, keyspace
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and loadbalancing policy.
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1 Includes and defines
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*/
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#ifndef _CASSANDRA_CONNECTIONPOOL_H
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#define _CASSANDRA_CONNECTIONPOOL_H
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#include "CassandraAdapter.h"
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using namespace std;
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//namespace to avoid name conflicts
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namespace cassandra {
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// Prototype class
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class CassandraAdapter;
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/*
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2.1 Wrapper class for cassandraAdapter objects
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This class is used in the connection pool, to hold
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and identify connections
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*/
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class CassandraConnection {
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public:
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CassandraConnection(bool mySingleNode, string myHostname,
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string myKeyspace) :
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singleNodeLoadBalancing(mySingleNode),
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hostname(myHostname), keyspace(myKeyspace),
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adapter(NULL) {
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}
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/*
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2.1.1 Get the singleNodeLoadBalancing policy for this connection
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*/
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bool getSingleNodeLoadBalancing() const {
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return singleNodeLoadBalancing;
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}
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/*
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2.1.2 Get the hostnamne for this connection
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*/
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string getHostname() const {
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return hostname;
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}
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/*
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2.1.3 Get the keyspace for this connection
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*/
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string getKeyspace() const {
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return keyspace;
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}
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/*
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2.1.4 Associate a cassandra adapter with this object
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*/
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void setAdapter(CassandraAdapter* myAdapter) {
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adapter = myAdapter;
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}
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/*
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2.1.5 Return the associated cassandra adapter
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*/
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CassandraAdapter* getAdapter() {
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return adapter;
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}
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/*
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2.1.6 Close and destory this connection
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*/
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virtual ~CassandraConnection() {
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if(adapter != NULL) {
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cout << "[ConnectionPool] Destroy connetion to: "
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<< hostname << " / " << keyspace << " / "
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<< singleNodeLoadBalancing << endl;
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adapter -> disconnect();
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delete adapter;
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adapter = NULL;
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}
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}
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/*
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2.4.7 Operator ==
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*/
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inline bool operator== (const CassandraConnection &connection) {
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if((singleNodeLoadBalancing == connection.getSingleNodeLoadBalancing()) &&
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(hostname == connection.getHostname()) &&
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(keyspace == connection.getKeyspace())) {
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return true;
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}
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return false;
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}
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private:
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bool singleNodeLoadBalancing;
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string hostname;
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string keyspace;
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CassandraAdapter* adapter;
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};
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/*
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2.2 This is our cassandra connection pool. It holds open connections for
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reusage. It is implemented as a singleton. The method destory is called
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during the destruction of the CassandraAlgebra.
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*/
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class CassandraConnectionPool {
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public:
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static CassandraConnectionPool* Instance();
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/*
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2.2.1 Request a connection the given hostname, keyspace and
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with the specified singleNodeLoadBalancing
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*/
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CassandraAdapter* getConnection(string myHostname,
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string myKeyspace, bool mySingleNode);
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/*
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2.2.2 Destory the connection pool
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*/
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void destroy();
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/*
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2.2.3 Destructor
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*/
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virtual ~CassandraConnectionPool() {
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destroy();
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}
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private:
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// We are a singleton, public constructors are not available
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CassandraConnectionPool() {};
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CassandraConnectionPool(CassandraConnectionPool const&) {};
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// Our connections
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vector<CassandraConnection*> connections;
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// The singleton instance
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static CassandraConnectionPool* instance;
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};
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}
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#endif |