Robotics Systems Commons

h1. Patterns

The @rsc::patterns@ namespace currently includes the following pattern implementations:

* @Singleton@ in file source:trunk/rsc/src/rsc/patterns/Singleton.h

* @Factory@ in file source:trunk/rsc/src/rsc/patterns/Factory.h

** @SingletonFactory@

** @ObservableFactory@ in file source:trunk/rsc/src/rsc/patterns/ObservableFactory.h

*** @ObservableSingletonFactory@

* @ContainerProxy@ in file source:trunk/rsc/src/rsc/patterns/ContainerProxy.h

** @AssociativeProxy@ in file source:trunk/rsc/src/rsc/patterns/AssociativeProxy.h

h2. Singleton

The @Singleton@ class can be used to ensure that at most one object of a given class exists at any time. It also encapsulates the creation and destruction of that object. Example:

<pre>

template<typename Key, typename Interface>

class SingletonFactory: public Singleton<SingletonFactory<Key, Interface> > ,

                        public Factory<Key, Interface> {

  friend class Singleton<SingletonFactory<Key, Interface> > ;

private:

  SingletonFactory();

};

</pre>

and

<pre>

SingletonFactory& factory = SingletonFactory::getInstance();

</pre>

h2. Factory

The @*Factory@ family of classes implements different variations of the "factory pattern":http://en.wikipedia.org/wiki/Factory_pattern. In all cases, keys of some type are used to identify implementations of a common interface that is specified as a template argument of the factory class. Example:

<pre>

typedef rsc::patterns::SingletonFactory<std::string, my_interface> my_factory;

</pre>

h2. ContainerProxy

The @ContainerProxy@ classes can be considered variants of the proxy pattern. The can be used to expose a modified interface to a container. For example, elements can be transformed on-the-fly when they are accessed.