libterralib-dev 4.0.0-5ubuntu1 / usr / include / terralib / kernel / TeCommunicator.h

/************************************************************************************
TerraLib - a library for developing GIS applications.
Copyright © 2001-2007 INPE and Tecgraf/PUC-Rio.

This code is part of the TerraLib library.
This library is free software; you can redistribute it and/or
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In no event shall INPE and Tecgraf / PUC-Rio be held liable to any party for direct,
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*************************************************************************************/
/*! \file TeCommunicator.h
    \brief This file contains  class to deal with inter-class communication.
	\author Emiliano F. Castejon <castejon@dpi.inpe.br>
*/

#ifndef TECOMMUNICATOR_H
  #define TECOMMUNICATOR_H
  
  #include "TeMutex.h"
  #include "TeAgnostic.h"

  #include <list>
  #include <algorithm>
  
  /**
   * @brief A macro for use when declaring class wrapper functions that will
   * be connected to a TeCommunicator instance.
   *
   * @param function_name The function name.
   * @param param_type The function pamrameter data type.
   * @param class_name The function's host class name.
   * @note The function body must be implemented.
   */
  #define TECOMMWRAPPER( function_name, param_type, class_name ) \
    protected : void function_name( const param_type& x ); \
    public : static void function_name( const param_type& x, void* objptr ) \
    { \
      class_name * casted_ptr = ( class_name * ) objptr; \
      casted_ptr->function_name( x ); \
    };
    
  /**
   * @class TeCommunicator
   * @brief This is the template class to deal with inter-class communication.
   * @note This is a thread-safe class.
   * @author Emiliano F. Castejon <castejon@dpi.inpe.br>
   * @ingroup Utils
   * @example TeCommunicator_test.cpp Shows how to use this class.
   */
  template< typename DataType >
  class TeCommunicator 
  {
    public :
    
      /**
       * @brief The objects wrapper function pointer.
       *
       * @param DataType The data type.
       * @param void A cast pointer to the active object instance.
       */        
      typedef void (*WrapperFuncPtrT)( const DataType&, void* );
            
      /**
       * @brief Default Constructor.
       *
       * @param host_obj_ptr A pointer to the active class instance.
       * @param wrapper_func_ptr A pointer to the class wrapper static
       * function.
       * @param enabled_flag The emission/reception enabling/disabling flag.
       */
      TeCommunicator( void* host_obj_ptr = 0,
        WrapperFuncPtrT wrapper_func_ptr = 0,
        bool enabled_flag = true );

      /**
       * @brief Default Destructor
       */
      ~TeCommunicator();
      
      /**
       * @brief Connects the current instance to a class wrapper function.
       *
       * @param host_obj_ptr A pointer to the active class instance.
       * @param wrapper_func_ptr A pointer to the class wrapper static
       * function.
       */      
      void setHostObj( void* host_obj_ptr = 0, 
        WrapperFuncPtrT wrapper_func_ptr = 0 );
      
      /**
       * @brief Connects the current instance to another active instance.
       *
       * @param external The external active instance reference.
       * @return true if OK, false on errors.
       */         
      bool connect( TeCommunicator< DataType>& external );
      
      /**
       * @brief Disconnects the current instance from all connected instances.
       */         
      void disconnect();
      
      /**
       * @brief Disconnects the current instance from another instance.
       *
       * @param external The external active instance reference.
       */        
      void disconnect( TeCommunicator< DataType>& external );
      
      /**
       * @brief Send data to all connected instances.
       *
       * @param data The data to be sent.
       */        
      void send( const DataType& data ) const;
      
      /**
       * @brief Enables/disables the data emission and rececption.
       *
       * @param enabled_flag The emission/reception enabling/disabling flag.
       */        
      void toggle( bool enabled_flag );      
      
      /**
       * @brief Check if this instance emission/reception is enabled.
       * @return true if enabled, false if disabled.
       */        
      bool isEnabled();          
      
    protected :
      
      /** @typedef TeCommunicator< DataType >* ComPtrT
       *  Communicator pointer type definition.
       */
      typedef TeCommunicator< DataType >* ComPtrT;
      
      /** @typedef std::list< ComPtrT > ContainerT
       *  Connected communicators pointers container type definition.
       */ 
      typedef std::list< ComPtrT > ContainerT;
      
      /** @typedef typename ContainerT::iterator ContItT
       *  Connected communicators pointers container iterator type definition.
       */       
      typedef typename ContainerT::iterator ContItT;      
      
      /**
       * @brief Used when another active instance requests to be connected to this
       * instance.
       *
       * @param my_pointer The pointer of the active instance.
       */       
      void ConnectMe( ComPtrT my_pointer );
      
      /**
       * @brief Used when another active instance requests to be disconnected from 
       * this instance.
       *
       * @param my_pointer The pointer of the active instance.
       */       
      void DisconnectMe( ComPtrT my_pointer );
      
      /**
       * @brief Used when another active instance sends data to this instance.
       *
       * @param data The sent data.
       */        
      inline void Receive( const DataType& data ) const; 
      
    private :
    
      /**
       * @brief A flag indication for enabled/disabled.
       */     
      bool emission_reception_enabled_;
    
      /**
       * @brief A pointer to the host object wrapper function.
       */      
      WrapperFuncPtrT wrapper_func_ptr_;
      
      /**
       * @brief A pointer to the host object active instance.
       */
      void* host_obj_ptr_;
      
      /**
       * @brief A list of pointers to the connected active instances.
       */
      mutable ContainerT connections_;
      
      /** @brief Thread lock instance. */
      mutable TeMutex lock_instance_;      
      
      /**
       * @brief Copy constructor not allowed.
       */
      TeCommunicator( const TeCommunicator< DataType >& ) {};
      
      /**
       * @brief Copy operation not allowed.
       */
      const TeCommunicator< DataType >& operator=( 
        const TeCommunicator< DataType >& ) {};
      
  };
  

  template< typename DataType >  
  TeCommunicator< DataType >::TeCommunicator( void* host_obj_ptr,
    WrapperFuncPtrT wrapper_func_ptr, bool enabled_flag )
  {
    wrapper_func_ptr_ = 0;
    host_obj_ptr_ = 0;
    emission_reception_enabled_ = enabled_flag;
    
    setHostObj( host_obj_ptr, wrapper_func_ptr );
  }
  
  
  template< typename DataType >  
  TeCommunicator< DataType >::~TeCommunicator()
  {
    disconnect();
  }
  
  
  template< typename DataType >  
  void TeCommunicator< DataType >::setHostObj( void* host_obj_ptr,
    WrapperFuncPtrT wrapper_func_ptr )
  {
    lock_instance_.lock();
    
//   TEAGN_TRUE_OR_THROW( (wrapper_func_ptr != 0), 
//      ( ( wrapper_func_ptr == 0 ) && ( host_obj_ptr == 0 ) ) || 
//      ( ( wrapper_func_ptr != 0 ) && ( host_obj_ptr != 0 ) ) ), 
//      "Invalid receiver_func_ptr/host_obj_ptr parameters" );
      
    wrapper_func_ptr_ = wrapper_func_ptr;
    host_obj_ptr_ = host_obj_ptr;
    
    lock_instance_.unLock();
  }
  
  
  template< typename DataType >
  bool TeCommunicator< DataType >::connect( 
    TeCommunicator< DataType>& external )
  {
    lock_instance_.lock();
    
//    if( ( wrapper_func_ptr_ == 0 ) || ( host_obj_ptr_ == 0 ) ) {
	  if( wrapper_func_ptr_ == 0 ) {
      lock_instance_.unLock();
      
      TEAGN_LOGERR( "Connecting a inactive communicator instance" );
      
      return false;
    }
    
    ContItT it = find( connections_.begin(), connections_.end(),
      &external );

    if( it == connections_.end() ) {
      connections_.push_back( &external );
      external.ConnectMe( this );
    }
    
    lock_instance_.unLock();
    
    return true;
  }
  

  template< typename DataType >
  void TeCommunicator< DataType >::disconnect()
  {
    lock_instance_.lock();
    
    ContItT it = connections_.begin();
    ContItT it_end = connections_.end();

    while( it != it_end ) {
      (*it)->DisconnectMe( this );
      
      ++it;
    }
    
    connections_.clear();
    
    lock_instance_.unLock();
  }
  
  
  template< typename DataType >
  void TeCommunicator< DataType >::disconnect( 
    TeCommunicator< DataType>& external )
  {
    lock_instance_.lock();
    
    ContItT it = find( connections_.begin(), connections_.end(),
      &external );
      
    if( it != connections_.end() ) {
      (*it)->DisconnectMe( this );
      connections_.erase( it );
    }
    
    lock_instance_.unLock();
  }

  
  template< typename DataType >
  void TeCommunicator< DataType >::ConnectMe( 
    ComPtrT my_pointer )
  {
    lock_instance_.lock();
    
    ContItT it = find( connections_.begin(), connections_.end(),
      my_pointer );
      
    if( it == connections_.end() ) {
      connections_.push_back( my_pointer );
    }
    
    lock_instance_.unLock();
  }

  
  template< typename DataType >
  void TeCommunicator< DataType >::DisconnectMe( 
    ComPtrT my_pointer )
  {
    lock_instance_.lock();
    
    ContItT it = find( connections_.begin(), connections_.end(),
      my_pointer );
      
    if( it != connections_.end() ) {
      connections_.erase( it );
    }
    
    lock_instance_.unLock();
  }
  
  
  template< typename DataType >
  void  TeCommunicator< DataType >::send( const DataType& data ) const
  {
    if( emission_reception_enabled_ )
    {
      lock_instance_.lock();
      
      ContItT it = connections_.begin();
      ContItT it_end = connections_.end();
      
      while( it != it_end ) {
        (*it)->Receive( data );
        
        ++it;  
      }
      
      lock_instance_.unLock();
    }
  }
  
  
  template< typename DataType >
  void  TeCommunicator< DataType >::toggle( bool enabled_flag )
  {
    emission_reception_enabled_ = enabled_flag;
  }
  
  
  template< typename DataType >
  bool TeCommunicator< DataType >::isEnabled()
  {
    return emission_reception_enabled_;
  }  

  
  template< typename DataType >
  inline void  TeCommunicator< DataType >::Receive( 
    const DataType& data ) const
  {
    if( emission_reception_enabled_ && ( wrapper_func_ptr_ != 0 ) ) 
    {
      lock_instance_.lock();
      
      wrapper_func_ptr_( data, host_obj_ptr_ );
      
      lock_instance_.unLock();
    }
  }
    
#endif