GraphFlow

A light library of multi-thread workflow

This library contains several abstract concepts: Graph, Module, Link and Message. Graph: A graph is a container that contains modules and links. Module: A module is an executable that shoule be implemented by user. Link: A link is a connector between modules. Message: Information that flows via link from one module to another.

example:

If we want to implement expression a + b = ? We may do it like this below: Create three modules, one module named "a" with default value 10, another module named "b" with default value 20, and the last module named "add" that prints out result of a+b.

1, Define message type IntMessage:

class IntMessage: public Message {
public:
  IntMessage(int value): mValue(value) {}
  virtual ~IntMessage() {}

  int getValue() {
    return mValue;
  }

private:
  int mValue;
};

2, Define Module Add, a and b:

class AddModule: public Module { public: AddModule(): Module(std::string("add")) {} ~AddModule() {}

  // user implemented
  virtual void PROCESS() {
    int a = getInputMessage("a")->getValue();
    int b = getInputMessage("b")->getValue();
    
    LOG("a + b = %d", a + b);
    std::cout << "a + b = " << a + b << std::endl;
  }

private:
};

class ModuleA: public Module {
public:
  ModuleA(): Module("a") {}
  ~ModuleA() {}

  // user implemented
  virtual void PROCESS() {
    spMessage message(new IntMessage(10));
    putOutputMessage(message);
  }
};

class ModuleB: public Module {
public:
  ModuleB(): Module("b") {}
  ~ModuleB() {}

  // user implemented
  virtual void PROCESS() {
    spMessage message(new IntMessage(20));
    putOutputMessage(message);
  }
};

3, start to build graph, run & stop

int main() { Graph *g = Graph::getInstance(); // get default graph instance

// create module a, b & add
Module *a = new ModuleA();
Module *b = new ModuleB();
Module *add = new AddModule();

// Add modules into graph
g->ADD_MODULE(a);
g->ADD_MODULE(b);
g->ADD_MODULE(add);

// Link modules
a->TO(add)->setLimit(1);
b->TO(add)->setLimit(1);

// run
if (g->RUN() < 0) {
   std::cout << "RUN failed!" << std::endl;
   return 0;
}

// stop
g->STOP();
return 0;

}

4, Finally, we build graph like this:

5, You can use this framework properly anywhere you want, and please contact me via liyepan@126.com if any question.