AOO410/main/cosv/inc/cosv/tpl/processor.hxx

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 * 
 * 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
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#ifndef CSV_TPL_PROCESSOR_HXX
#define CSV_TPL_PROCESSOR_HXX

// USED SERVICES




namespace csv
{


/** Implements an acyclic visitor pattern. This is the abstract
    base for the classes doing the work (the "visitors").
*/
class ProcessorIfc
{
  public:
    virtual             ~ProcessorIfc() {}
};



/** Implements an acyclic visitor pattern. This is the abstract
    base for the classes to be processed (the "visitables").
*/
class ConstProcessorClient
{
  public:
    virtual             ~ConstProcessorClient() {}

    void                Accept(
                            ProcessorIfc &  io_processor ) const
                            { do_Accept(io_processor); }
  private:
    virtual void        do_Accept(
                            ProcessorIfc &  io_processor ) const = 0;
};

/** Implements an acyclic visitor pattern. This is the abstract
    base for the classes to be processed (the "visitables").
*/
class ProcessorClient
{
  public:
    virtual             ~ProcessorClient() {}

    void                Accept(
                            ProcessorIfc &  io_processor )
                            { do_Accept(io_processor); }
  private:
    virtual void        do_Accept(
                            ProcessorIfc &  io_processor ) = 0;
};





/** Typed base for "visitor" classes, leaving the visited
    object const.

    @see ProcessorIfc
    @see Processor<>
*/
template <typename X, typename R = void>
class ConstProcessor
{
  public:
    virtual             ~ConstProcessor() {}

    R                   Process(
                            const X &           i_object )
                        { return do_Process(i_object ); }
 private:
    virtual R           do_Process(
                            const X &           i_object ) = 0;
};


/** Typed base for "visitor" classes which may change the visited
    object.

    @see ProcessorIfc
    @see ConstProcessor<>
*/
template <typename X, typename R = void>
class Processor
{
  public:
    virtual             ~Processor() {}

    R                   Process(
                            X &                 i_object )
                        { return do_Process(i_object ); }
 private:
    virtual R           do_Process(
                            X &                 i_object ) = 0;
};


template <class C>
inline void
CheckedCall( ProcessorIfc &  io_processor,
             const C &       i_client )
{
    ConstProcessor<C> *
        pProcessor = dynamic_cast< csv::ConstProcessor<C> * >
                        (&io_processor);
    if (pProcessor != 0)
        pProcessor->Process(i_client);
}

template <class C>
inline void
CheckedCall( ProcessorIfc &  io_processor,
             C &             io_client )
{
    Processor<C> *
        pProcessor = dynamic_cast< csv::Processor<C> * >
                        (&io_processor);
    if (pProcessor != 0)
        pProcessor->Process(io_client);
}

template <class C>
inline void
AssertedCall( ProcessorIfc &  io_processor,
              const C &       i_client )
{
    ConstProcessor<C> *
        pProcessor = dynamic_cast< csv::ConstProcessor<C> * >
                        (&io_processor);
    csv_assert( pProcessor != 0
                && "csv::AssertedCall() failed. Processed object did not match processor." );
    pProcessor->Process(i_client);
}

template <class C>
inline void
AssertedCall( ProcessorIfc &  io_processor,
              C &             io_client )
{
    Processor<C> *
        pProcessor = dynamic_cast< csv::Processor<C> * >
                        (&io_processor);
    csv_assert( pProcessor != 0
                && "csv::AssertedCall() failed. Processed object did not match processor." );
    pProcessor->Process(io_client);
}




}   // namespace csv
#endif