seiscomp-training/include/seiscomp/core/message.h

/***************************************************************************
 * Copyright (C) gempa GmbH                                                *
 * All rights reserved.                                                    *
 * Contact: gempa GmbH (seiscomp-dev@gempa.de)                             *
 *                                                                         *
 * GNU Affero General Public License Usage                                 *
 * This file may be used under the terms of the GNU Affero                 *
 * Public License version 3.0 as published by the Free Software Foundation *
 * and appearing in the file LICENSE included in the packaging of this     *
 * file. Please review the following information to ensure the GNU Affero  *
 * Public License version 3.0 requirements will be met:                    *
 * https://www.gnu.org/licenses/agpl-3.0.html.                             *
 *                                                                         *
 * Other Usage                                                             *
 * Alternatively, this file may be used in accordance with the terms and   *
 * conditions contained in a signed written agreement between you and      *
 * gempa GmbH.                                                             *
 ***************************************************************************/


#ifndef SEISCOMP_CORE_MESSAGE_H
#define SEISCOMP_CORE_MESSAGE_H

#include <seiscomp/core/baseobject.h>


namespace Seiscomp {
namespace Core {
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// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
DEFINE_SMARTPOINTER(Message);

/**
 * The MessageIterator is an iterator that iterates over the objects
 * attached to a message. Not all message types support attachments
 * what resulted in a generic iterator concept. Each derived message
 * type that wants to implement its iteration has to provide an
 * implementation class derived from MessageType::Impl
 * The iterator protocol looks like this:
 * \code
 * for ( Iterator it = msg->iter(); *it != nullptr; ++it ) {
 *   BaseObject* o = *it;
 *   // do something with o
 * }
 * \endcode
 *
 */
class SC_SYSTEM_CORE_API MessageIterator {
	public:
		//! Implementation class for a message iterator
		class Impl {
			public:
				virtual ~Impl() {}

				//! Clones the iterator implementation
				virtual Impl* clone() const = 0;

				//! Returns the current element
				virtual Seiscomp::Core::BaseObject* get() const = 0;

				//! Go to the next element
				virtual void next() = 0;
		};


	public:
		MessageIterator();
		MessageIterator(const MessageIterator& iter);
		~MessageIterator();

	protected:
		MessageIterator(Impl*);

	public:
		Seiscomp::Core::BaseObject* get() const;

		MessageIterator& operator=(const MessageIterator& it);
		Seiscomp::Core::BaseObject* operator*() const;

		MessageIterator& operator++();
		MessageIterator& operator++(int);

	private:
		Impl* _impl;

	friend class Message;
};


class SC_SYSTEM_CORE_API Message : public BaseObject {
	DECLARE_SC_CLASS(Message);
	DECLARE_SERIALIZATION;

	// ----------------------------------------------------------------------
	//  Xstruction
	// ----------------------------------------------------------------------
	protected:
		//! Constructor
		Message();

	public:
		//! Destructor
		~Message();


	// ----------------------------------------------------------------------
	//  Public Interface
	// ----------------------------------------------------------------------
	public:
		/**
		 * Returns an iterator to iterate through the attachments.
		 * To filter a particular object type, a class typeinfo can
		 * be used to do that.
		 * E.g., to filter only object of type A (and derived), use
		 * A::TypeInfo() as input parameter.
		 * \code
		 * MessageIterator it = msg->iter(A::TypeInfo());
		 * while ( it.next() ) {
		 *   A* a = static_cast<A*>(*it);
		 * }
		 * \endcode
		 * @param typeInfo The object type filter
		 * @return The iterator
		 */
		MessageIterator iter() const;

		/**
		 * @return Returns the number of objects attached to a message
		 */
		virtual int size() const;

		/**
		 * Checks whether a message is empty or not.
		 * @retval true The message is empty
		 * @retval false The message is not empty
		 */
		virtual bool empty() const = 0;

		/**
		 * Erases the content of the message.
		 */
		virtual void clear() {}


	protected:
		/**
		 * Returns an iterator implementation for a particular message.
		 * This method has to be implemented in derived classes to provide
		 * generic iteration.
		 * @return The implementation.
		 */
		virtual MessageIterator::Impl* iterImpl() const;
};
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// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
}
}
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// >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#endif