part.h

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/*******************************************************************************
 * wallaroo - A library for configurable creation and wiring of C++ classes.
 * Copyright (C) 2012 Daniele Pallastrelli
 *
 * This file is part of wallaroo.
 * For more information, see http://wallaroolib.sourceforge.net/
 *
 * Boost Software License - Version 1.0 - August 17th, 2003
 *
 * Permission is hereby granted, free of charge, to any person or organization
 * obtaining a copy of the software and accompanying documentation covered by
 * this license (the "Software") to use, reproduce, display, distribute,
 * execute, and transmit the Software, and to prepare derivative works of the
 * Software, and to permit third-parties to whom the Software is furnished to
 * do so, all subject to the following:
 *
 * The copyright notices in the Software and this entire statement, including
 * the above license grant, this restriction and the following disclaimer,
 * must be included in all copies of the Software, in whole or in part, and
 * all derivative works of the Software, unless such copies or derivative
 * works are solely in the form of machine-executable object code generated by
 * a source language processor.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
 * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
 * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ******************************************************************************/

#ifndef WALLAROO_PART_H_
#define WALLAROO_PART_H_

#include <string>
#include <sstream>
#include "exceptions.h"
#include "cxx0x.h"
#include "dependency.h"
#include "deserializable_value.h"

namespace wallaroo
{

// forward declaration:
class Plugin;

class RegToken
{
public:
    Part* GetPart() const { return part; }
private:
    friend class Part;
    RegToken( Part* d ) : part( d ) {}
    Part* part;
};

class Part
{
public:
    // we need to make Part virtual, to use dynamic_cast
    virtual ~Part() {}

    void Wire( const std::string& dependency, const cxx0x::shared_ptr< Part >& part )
    {
        Dependencies::iterator i = dependencies.find( dependency );
        if ( i == dependencies.end() ) throw ElementNotFound( dependency );
        ( i -> second ) -> Link( part );
    }

    // NOTE: we pass value as const reference to allow the effective specialization of string
    template < typename T >
    void SetAttribute( const std::string& attribute, const T& value )
    {
        std::ostringstream stream;
        if ( !( stream << std::boolalpha << value ) ) throw WrongType();
        SetStringAttribute( attribute, stream.str() );
    }

    bool MultiplicitiesOk() const
    {
        for ( 
            Dependencies::const_iterator i = dependencies.begin();
            i != dependencies.end();
            ++i
        )
            if ( ! i -> second -> WiringOk() )
                return false;
        return true;
    }

    virtual void Init() {};

protected:
    RegToken RegistrationToken()
    { 
        return RegToken( this );
    }
private:
    // this method should only be invoked by Class
    // to add the reference counter for the shared library.
    template < class T1, class T2 > friend class Class;
    void Source( const cxx0x::shared_ptr< Plugin >& p )
    {
        plugin = p;
    }

    // this method should only be invoked by the dependencies of this part
    // to register itself into the dependencies table.
    template < typename T, typename P, template < typename X > class Ownership >
    friend class Collaborator;
    void Register( const std::string& id, Dependency* c )
    {
        dependencies[ id ] = c;
    }

    // this method should only be invoked by the attributes of this part
    // to register itself into the attributes table.
    template < class T > friend class Attribute;
    void Register( const std::string& id, DeserializableValue* attribute )
    {
        attributes[ id ] = attribute;
    }

    // set attribute to a value represented as string.
    // throws ElementNotFound if the attribute doesn't exist.
    // throws WrongType if @c value is not a valid representation for the type of the attribute
    void SetStringAttribute( const std::string& attribute, const std::string& value )
    {
        Attributes::iterator i = attributes.find( attribute );
        if ( i == attributes.end() ) throw ElementNotFound( attribute );
        ( i -> second ) -> Value( value );
    }

    typedef cxx0x::unordered_map< std::string, Dependency* > Dependencies;
    Dependencies dependencies;

    typedef cxx0x::unordered_map< std::string, DeserializableValue* > Attributes;
    Attributes attributes;

    cxx0x::shared_ptr< Plugin > plugin; // optional shared ptr to plugin, to release the shared library when is no more used
};


template <>
inline void Part::SetAttribute( const std::string& attribute, const std::string& value )
{
    // Optimization: with strings we don't need conversion
    SetStringAttribute( attribute, value );
}

} // namespace

#endif