Blackboard

This thread safe data structure allows you to store data of all types in one data structure. It requires c++ 11. This repository is a fork of MitchCroft/Blackboard, but I removed the singleton feature and optimized it a bit, so that you can create multiple instances of the blackboard.

Usage:

#include "Blackboard.h"

int main(){
    Util::Blackboard b;
    b.write("key", 5);
    int value = b.read<int>("key");
    return 0;
}

It is also possible to store your own data types, but they need to have valid default and copy constructures defined, as well as the assignment operator.

#include "Blackboard.h"

class Test{
    int m_val;
public:
    Test(){
        m_val = 1;
    }
};

int main(){
    Util::Blackboard b;
    Test t1;
    b.write("key", t);
    Test t2 = b.read<Test>("key");
    return 0;
}

You can also define callbacks, whitch get called when a value gets added or changed on the blackboard. By passing false as the third argument, no listener gets called. There are three diffrent types of functions you can define as callbacks:

1. void foo(const std::string& key);
2. void foo(const T& val );
3. void foo(const std::string& key, const T& val);

    #include "Blackboard.h"
    
    int main(){
        Util::Blackboard b;
        b.subscribe<int>("key",
        [](const std::string& key, const int& val) {
		    std::cout << "Entry with the key " << key <<
		    " changed to " << val << '\n';
	    });
	    
        b.write("key", 5); //lamda function gets called
        b.write("key", 6, false); //no call to lamda function
        
        return 0;
    }

Thread safety:

All functions are thread safe for reading and writing data to the blackboard. If you don't need the thread safety, define BB_NO_THREAD before including the header file, to increase the performance.