Jump to content
  • Advertisement
Sign in to follow this  
JoshuaWaring

Static Classes in c++

This topic is 1592 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I've been passing an GUIDManager around in my project to where ever it's been needed, this was causing some problems. I was wondering if making the whole class static would cause any issues? Before I start correcting all reference to this class, I want to make sure that I won't come into some issue in the future.

namespace Pro{
	typedef unsigned int GUID; 
		class GUIDLookup{   
			static unsigned int allocatedBitCount;
			static std::unordered_map<std::string, GUID> nameMapping;
			static std::stack<unsigned int> releasedGUIDs;
			static GUID newGUID();
		public: 
			 
			static GUID newGUID(const std::string& name);
			static void releaseGUID(const std::string& name);
			static void releaseGUID(GUID);
			static GUID getGUIDFromName(const std::string& name);
			static std::string getName(GUID _id);
		}; 
}

 

Edited by Joshhua5

Share this post


Link to post
Share on other sites
Advertisement
What is your real problem you are trying to solve? You don't want to pass an object around?

There are reasons to mark a function as static, usually when you have a reason not to need the this pointer.

There are times it is a solution to problems, but with the very brief description, I don't think that is the answer. I think the deeper problem is the "manager" class not having a single responsibility. Most "manager" classes are a symptom of a design flaw.

In this case your "manager" looks like a name/id lookup. Is there more to the class?

Share this post


Link to post
Share on other sites

I was cleaning up my code and thought one way would be to stop passing around the GUIDManager.

  

You're right the it is a name/id lookup.

 

I've also decided to change the name to GUIDLookup

Edited by Joshhua5

Share this post


Link to post
Share on other sites
Looking over your other posts on trying to get Lua objects to work with game objects, I'm guessing this "manager" class actually belongs as a part of a larger class. It probably belongs as part of a resource cache system. A resource cache can load and unload objects if needed, find the objects if they exist, and potentially (depending on how you want to do it) load up a proxy while you wait for the resources to load. One facet of a resource cache is to translate names into object pointers.

When you try to name a class, the name "manager" is usually a clear marker that you aren't sure about the classes responsibilities. Sometimes the class is really a subset of another class responsibility, sometimes it is a collection of too many responsibilities.

Of course, if this bit of code has nothing to do with those earlier discussions then it could be part of a totally different system, but the concern of a generic "manager" rather than a specific purpose still remains.

Share this post


Link to post
Share on other sites

Well as of right now, Lua will refer to an object via it's name, but before Lua performs a required task, it'll get the ID of the name and use when it operates on the C++ code.

 

The only problem is that the functions that Lua calls at times require the GUIDLookup. All functions that Lua calls must be static, which means I either have to pass the GUIDLookup via Lua's stack or have the GUIDLookup static.

Edited by Joshhua5

Share this post


Link to post
Share on other sites
There is no such thing as a "static class". You can make member functions static but these will only be able to access static member variables. To make the "whole" class accessible from anywhere in the program use the singleton pattern http://en.wikipedia.org/wiki/Singleton_pattern : You add one static method only to return the instance.

Use this sparingly! Too many of these is a sign of a bad class structure really ( as is the use of the word "manager" in class-names ;) though there are always exceptions if you have a valid reason!

Share this post


Link to post
Share on other sites

I'm trying to work on my class structure and naming, what's why I keep refactoring my project :P

 

What would you call my example up above? because it doesn't fit into a Singleton.

Share this post


Link to post
Share on other sites
I've heard the term Monostate used for similar things.

Personally I don't like singleton or monostate implementations much. If you have some code that needs GUID mapping lookup, just build a lightweight mapping wrapper that you can use as a component (i.e. member variable) of any object that needs that lookup mapping.


For your Lua code, I'd suggest setting up the mapping in your Lua context wrapper (assuming you did it right and you have one!) and then just use a thunk (standalone function that can find your Lua data, including the GUID mappings, and do whatever). Edited by ApochPiQ

Share this post


Link to post
Share on other sites

I'm trying to work on my class structure and naming, what's why I keep refactoring my project :P
 
What would you call my example up above? because it doesn't fit into a Singleton.


I see no reason why this class would not work as a singleton. In fact, having the word manager in the name almost indicates it is a singleton, which is why it makes people sense there's some problem as you should have as little as possible of these.

Share this post


Link to post
Share on other sites

It was just according to the Singleton pattern there's a static function that returns a instance of the class, which is then called upon.

Instead of mine which is calling static functions of the class.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!