diff options
Diffstat (limited to 'cpp/src/qpid')
| -rw-r--r-- | cpp/src/qpid/framing/Visitor.h | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/cpp/src/qpid/framing/Visitor.h b/cpp/src/qpid/framing/Visitor.h new file mode 100644 index 0000000000..fd55c48c60 --- /dev/null +++ b/cpp/src/qpid/framing/Visitor.h @@ -0,0 +1,71 @@ +#ifndef QPID_FRAMING_VISITOR_H +#define QPID_FRAMING_VISITOR_H + +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + * + */ + +#include "Handler.h" + +#include <boost/mpl/vector.hpp> +#include <boost/mpl/inherit.hpp> +#include <boost/mpl/inherit_linearly.hpp> +#include <boost/type_traits/add_reference.hpp> + +namespace qpid { +namespace framing { + +// FIXME aconway 2007-07-30: Drop linking from handlers, use +// vector<shared_ptr<Handler<T> > for chains. + +/** @file Visitor pattern for Handlers. */ + +/** + * Interface for a handler visitor, inherits Handler<T> for each T in Types + *@param Types A boost::mpl type sequence, e.g. boost::mpl::vector. + */ +template <class Types> +struct HandlerVisitor : public boost::mpl::inherit_linearly< + Types, boost::mpl::inherit<boost::mpl::_1, Handler<boost::mpl::_2> > + >::type +{}; + +/** Base class for hierarchy of objects visitable by Visitor */ +template <class Visitor> +struct AbstractVisitable { + virtual ~AbstractVisitable() {} + typedef Visitor VisitorType; + virtual void accept(Visitor& v) = 0; +}; + +/** Base class for concrete visitable types, implements accept. + * @param T parameter type for appropriate Handler, may be a reference. + * @param Base base class to inherit from. + */ +template <class T, class Base> +struct ConcreteVisitable : public Base { + typedef typename boost::add_reference<T>::type TRef; + void accept(typename Base::VisitorType& v) { + static_cast<Handler<T>& >(v).handle(static_cast<TRef>(*this)); + } +}; + +}} // namespace qpid::framing + +#endif /*!QPID_FRAMING_VISITOR_H*/ |
