ExtendedEventChannel.h

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 *
 * Copyright (c) 2008-2010 Michael Schulze <mschulze@ivs.cs.uni-magdeburg.de>
 * Copyright (c) 2010 Marcus Förster <marcusfoerster1@gmx.de>
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#ifndef __ExtendedEventChannel_h__
#define __ExtendedEventChannel_h__

#include "mw/common/Subject.h"

#include "boost/mpl/eval_if.hpp"
#include "boost/mpl/vector.hpp"
#include "mw/attributes/AttributeSet.h"
#include "mw/attributes/detail/RequirementChecker.h"
#include "config/type_traits/contains_type.h"

#include "assert/staticwarning.h"

IF_CONTAINS_TYPE_(attributeProvision);

namespace famouso {
    namespace mw {
        namespace api {

            template <typename EC, typename Requirement, bool compileError = true>
            class ExtendedEventChannel : public EC {
                public:
                    ExtendedEventChannel(const Subject& subject) : EC(subject) { }

                private:
                    // The event channel handler which is provided by the given
                    //  event channel
                    typedef typename EC::eventChannelHandler ECH;

                    // Find out if the event channel handler defined a provision
                    static const bool echHasProvision =
                            if_contains_type_attributeProvision<ECH>::value;

                    // Issue a warning if it did not
                    FAMOUSO_STATIC_ASSERT_WARNING(
                        echHasProvision,
                        no_provision_defined_by_event_channel_handler,
                        (EC)
                    );

                    // Dummy struct for wrapping an empty provision (in the case that
                    //  the handler did not define a provision)
                    struct EmptyProvisionProvider {
                            typedef attributes::AttributeSet<
                                     boost::mpl::vector<>
                                    > attributeProvision;

                            typedef EmptyProvisionProvider type;
                    };

                    // Attribute provision of the given event channel handler (or an
                    //  an empty provision if the handler did not define any)
                    typedef typename boost::mpl::eval_if_c<
                                      echHasProvision,
                                      ECH,
                                      EmptyProvisionProvider
                                     >::type::attributeProvision echProvision;

                    // The requirement of this event channel given by the attribute set above
                    typedef Requirement ecRequirement;

                    // The type which checks the provision of the ECH against the given
                    //  requirement (This one does the actual work)
                    typedef typename attributes::detail::RequirementChecker<
                                      echProvision,
                                      ecRequirement,
                                      compileError
                                     >::type checker;
            };

        } // namespace api
    } // namespace mw
} // namespace famouso

#endif /* __PublisherEventChannel_h__ */