Class Poco::Activity

File Information

Library: Foundation
Package: Threading
Header: Poco/Activity.h

Description

This template class helps to implement active objects. An active object uses threads to decouple method execution from method invocation, or to perform tasks autonomously, without intervention of a caller.

An activity is a (typically longer running) method that executes within its own task. Activities can be started automatically (upon object construction) or manually at a later time. Activities can also be stopped at any time. However, to make stopping an activity work, the method implementing the activity has to check periodically whether it has been requested to stop, and if so, return. Activities are stopped before the object they belong to is destroyed. Methods implementing activities cannot have arguments or return values.

Activity objects are used as follows:

class ActiveObject
{
public:
    ActiveObject(): 
        _activity(this, &ActiveObject::runActivity)
    {
        ...
    }

    ...

protected:
    void runActivity()
    {
        while (!_activity.isStopped())
        {
            ...
        }
    }

private:
    Activity<ActiveObject> _activity;
};