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This page last changed on Jan 21, 2009 by fpy.
This page show a typical implementation of a reactor that connects TREX to an external system. To illustrate this I have taken the VCSAdapter class that provide a connection to AUV Linux system using socket connection. The code here can be found under TREX/ctd2007
Reactor expected interface
#ifndef H_VCSAdapter
#define H_VCSAdapter
# include "Adapter.hh"
namespace TREX {
/** @brief Linux Interface to VCS and StatePublisher
*
* This class implenments a TREX reactor that provides a connection
* to VcsServer and StatePublisher.
*
* @author Frederic Py <fpy@mbari.org>
*/
class VCSAdapter: public Adapter {
public:
/** @brief Constructor
*
* This consdtructor is usually called by the factory that manages
* configuration parsing
*
* @param agentName Name of the agent that will execute this reactor.
* @param confgData CXonfiguration data for this reactor
*/
VCSAdapter(LabelStr const &agentName, TiXmlElement const &configData);
/** @brief Destructor
*/
~VCSAdapter();
/** @brief handle agent initialization signal.
*
* This callback is called to indicate to reactors that the agent wait for
* them to initialize.
* In this case this is where TREX is initailizing the connections to
* VCS and wait for feedback from the VCS to be ready to start the misssion.
*
* @param initialTick value of the initial tick (usually 0)
* @param serversByTimeline mapping from timeline name to the connection to its owner
* @param observer reference to the place where observation of thi reactor should be sent to
*/
void handleInit(TICK initialTick, std::map<double, ServerId> const &serversByTimeline,
ObserverId const &observer);
/** @brief Obsservation production
*
* For uch a reactor this method is called while the agent ex-pect the reactort to produce its new
* observations. In this case this is whaen the reactor collect all the informations sent from VCS and convert it in
* @c Observations
*
* @retval true if no specific problem
* @retval false in case of a critical issue
*/
bool synchronize();
/** @brief Signal sent by the agent to indicate that a new tick has been started
*/
void handleTickStart();
/** @brief Notification of a new observation coming from an external agent
*
* @note This hould never happen with this reactor as it does not obsserve anything in the agent
*/
void notify(Observation const &obs);
/** @brief Notification of a goal request
*
* This method indicate a new objective received fromn anopther reactor. In the case of this reactor
* this goal is generally reflecting the execution of a new behavior.
*
* @param goal The objective as requested by the reactor
*/
void handleRequest(GoalId const &goal);
/** @brief Notification of a goal recall
*
* This method indicate to the reactor that a previously requested objective
* is not part of the plan anymore and should -- if possible -- canceled.
*
* @param goal The objective as requested by the reactor
*/
void handleRecall(GoalId const &goal);
private:
/* Internal things specific to this reactor
*/
};
}
#endif
Declare a new reactor type to the factory
At the beginning of VCSAdapter.cc one can see
namespace TREX {
namespace {
DeclareReactor<VCSAdapter> decl("VCSAdapter");
}
}
This static variable generate a new factory producer that will call the VCSAdapter constructor when it will identify a "VCSAdapter" configuration in the XZML file. For example the following xml file will trigger this :
<Config>
<TeleoReactor name="vcs" component="VCSAdapter"/>
<TeleoReactor name="exec" component="DeliberativeReactor"
lookAhead="5" latency="1" solverConfig="exec.solver.cfg"/>
<TeleoReactor name="skipper" component="DeliberativeReactor"
lookAhead="36000" latency="60" solverConfig="skipper.solver.cfg" />
</Config>
What is passed as argument to the constructor is the name of the agent (not showed here) and a C++ representation of the XML field that triggered the creation. In this case:
<TeleoReactor name="vcs" component="VCSAdapter"/>
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