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changed Singleton to public-constructor variety

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This commit is contained in:
James Turk 2005-03-15 18:51:00 +00:00
parent ca927a0672
commit 0ef66e5017
1 changed files with 29 additions and 35 deletions
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62
include/util/Singleton.hpp
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@ -5,12 +5,11 @@
// James Turk (jpt2433@rit.edu)
//
// Version:
// $Id: Singleton.hpp,v 1.6 2005/03/04 13:06:49 cozman Exp $
// $Id: Singleton.hpp,v 1.7 2005/03/15 18:51:00 cozman Exp $
#ifndef PHOTON_UTIL_SINGLETON_HPP
#define PHOTON_UTIL_SINGLETON_HPP
#include <memory>
#include <boost/utility.hpp>
#include "exceptions.hpp"
@ -28,33 +27,23 @@ namespace util
// (code)
// YourClass : public Singleton<Class>
// {
// // class specific data
//
// // Singleton-required code
// private:
// // Singleton-required code
// YourClass();
// ~YourClass();
//
// friend class util::Singleton<YourClass>;
// friend class std::auto_ptr<YourClass>;
// // class definition
// };
// (end)
//
// Using The Singleton:
// (code)
// YourClass::initialize(); //optional
// new YourClass;
// YourClass& yc(YourClass::getInstance());
//
// // use yc
//
// YourClass::destroy(); //optional
// YourClass::destroy();
// (end)
template<class T>
class Singleton : public boost::noncopyable
{
public:
// Function: initialize
// Initialize the instance of the singleton, can be done explicitly if
// order of construction matters. Will be done on first call to
@ -71,55 +60,60 @@ public:
static T& getInstance();
protected:
virtual ~Singleton()=0; // allow inheritance
Singleton();
virtual ~Singleton(); // allow inheritance
private:
static std::auto_ptr<T> instance_;
static T* instance_;
};
// template implementation
template<class T>
Singleton<T>::Singleton()
{
if(instance_ != 0)
{
throw PreconditionException("Attempt to double-initialize singleton.");
}
instance_ = static_cast<T*>(this); // cast self to type of T*
}
template<class T>
Singleton<T>::~Singleton()
{
}
template<class T>
void Singleton<T>::initialize()
{
if(instance_.get() != 0)
{
throw PreconditionException("Attempt to double-initialize singleton.");
}
instance_ = std::auto_ptr<T>(new T);
}
template<class T>
void Singleton<T>::destroy()
{
if(instance_.get() == 0)
if(instance_ == 0)
{
throw PreconditionException("Attempt to destroy null singleton.");
}
instance_.reset();
if(instance_)
{
delete instance_;
instance_ = 0;
}
}
template<class T>
T& Singleton<T>::getInstance()
{
if(instance_.get() == 0)
if(instance_ == 0)
{
initialize(); //initialize if nonexistant
throw PreconditionException("Attempt to access null singleton.");
}
return *instance_; //return dereferenced version
return *instance_; //return dereferenced instance
}
template<class T>
std::auto_ptr<T> Singleton<T>::instance_(0);
T* Singleton<T>::instance_(0);
}
}