context_factory.hpp

ncbi源码

/*
 * ===========================================================================
 * PRODUCTION $Log: context_factory.hpp,v $
 * PRODUCTION Revision 1000.0  2003/10/31 20:19:45  gouriano
 * PRODUCTION PRODUCTION: IMPORTED [ORIGINAL] Dev-tree R1.7
 * PRODUCTION
 * ===========================================================================
 */

#ifndef GUI_CORE___CONTEXT_FACTORY__HPP
#define GUI_CORE___CONTEXT_FACTORY__HPP

/*  $Id: context_factory.hpp,v 1000.0 2003/10/31 20:19:45 gouriano Exp $
 * ===========================================================================
 *
 *                            PUBLIC DOMAIN NOTICE
 *               National Center for Biotechnology Information
 *
 *  This software/database is a "United States Government Work" under the
 *  terms of the United States Copyright Act.  It was written as part of
 *  the author's official duties as a United States Government employee and
 *  thus cannot be copyrighted.  This software/database is freely available
 *  to the public for use. The National Library of Medicine and the U.S.
 *  Government have not placed any restriction on its use or reproduction.
 *
 *  Although all reasonable efforts have been taken to ensure the accuracy
 *  and reliability of the software and data, the NLM and the U.S.
 *  Government do not and cannot warrant the performance or results that
 *  may be obtained by using this software or data. The NLM and the U.S.
 *  Government disclaim all warranties, express or implied, including
 *  warranties of performance, merchantability or fitness for any particular
 *  purpose.
 *
 *  Please cite the author in any work or product based on this material.
 *
 * ===========================================================================
 *
 * Authors:  Mike DiCuccio
 *
 * File Description:
 *    CContextFactory -- provides standard mechanisms for creating and managing
 *                       named plugin contexts
 */

#include <gui/core/plugin_exception.hpp>
#include <gui/core/plugin_factory.hpp>


BEGIN_NCBI_SCOPE


//
// class CContextFactory defines a standard templated interface for maintenance
// of a context-aware plugin.
//
// This class stores a list of explicitly named and managed contexts.  The
// framework will marshall contexts per a user's requests and requirements.
// There is one specially named context - the "empty name" context (where name
// is the empty string).  This is the default context used by a given plugin,
// where a default context is supported (i.e., data loaders, algorithms -
// default context doesn't necessarily match a view's notion of context).
//
template <class PluginType>
class CContextFactory : public CPluginFactory<PluginType>
{
private:

    // we maintain a map of name to context
    typedef map<string, CRef<PluginType> > TContexts;
    TContexts m_Contexts;

protected:

    // modes of operation for context creation
    enum EContextCreateMode {
        eImplicitCreate,
        eNoImplicitCreate
    };

    // query to see if a given named context exists
    bool x_HasContext(const string& name) const
    {
        typename TContexts::const_iterator iter = m_Contexts.find(name);
        return (iter != m_Contexts.end());
    }

    // main context request interface
    PluginType& x_GetContext(const string& name,
                             const objects::CPluginArgSet& args,
                             EContextCreateMode mode = eImplicitCreate)
    {
        typename TContexts::iterator iter = m_Contexts.find(name);
        if (iter != m_Contexts.end()) {
            return *(iter->second);
        }

        if (mode == eNoImplicitCreate) {
            NCBI_THROW(CPluginException, eNotSupported,
                       "Attempted to access non-existent context");
        }

        CRef<PluginType> context(new PluginType());
        m_Contexts[name] = context;
        return *context;
    }


    // overloaded context creation function
    virtual void x_OnCreateContext(const string& name,
                                   const objects::CPluginArgSet& args,
                                   objects::CPluginReply& reply)
    {
        if (x_HasContext(name)) {
            reply.SetStatus(objects::eMessageStatus_ignored);
            return;
        }

        // we've requested a named context be created
        x_GetContext(name, args);
        reply.SetStatus(objects::eMessageStatus_success);
    }

    // overloaded context destruction function
    virtual void x_OnDestroyContext(const string& name,
                                    objects::CPluginReply& reply)
    {
        if ( !x_HasContext(name) ) {
            reply.SetStatus(objects::eMessageStatus_ignored);
            return;
        }

        m_Contexts.erase(m_Contexts.find(name));
        reply.SetStatus(objects::eMessageStatus_success);
    }
};



END_NCBI_SCOPE

/*
 * ===========================================================================
 * $Log: context_factory.hpp,v $
 * Revision 1000.0  2003/10/31 20:19:45  gouriano
 * PRODUCTION: IMPORTED [ORIGINAL] Dev-tree R1.7
 *
 * Revision 1.7  2003/08/22 15:54:48  dicuccio
 * General clean-up:  Removed unneeded export specifiers from templates; removed
 * 'USING_SCOPE(objects)'
 *
 * Revision 1.6  2003/07/14 10:56:57  shomrat
 * Plugin messageing system related changes
 *
 * Revision 1.5  2003/06/25 16:59:41  dicuccio
 * Changed CPluginHandle into a pointer-to-implementation (the previous
 * implementation is now the pointer held).  Lots of #include file clean-ups.
 *
 * Revision 1.4  2003/06/20 14:44:36  dicuccio
 * Revamped handling of plugin registration.  All plugin factories now derive
 * from CPluginFactoryBase; CPluginFactory is a template.  There is a new
 * requirement for derived plugin handlers of all types (each must implement a
 * static function of the form 'static void GetInfo(CPluginInfo&)')
 *
 * Revision 1.3  2003/02/24 13:00:17  dicuccio
 * Renamed classes in plugin spec:
 *     CArgSeg --> CPluginArgSet
 *     CArgument --> CPluginArg
 *     CPluginArgs --> CPluginCommand
 *     CPluginCommands --> CPluginCommandSet
 *
 * Revision 1.2  2003/02/21 16:44:13  dicuccio
 * Added Win32 export specifiers for new plugin library.  Fixed compilation
 * issues for Win32.
 *
 * Revision 1.1  2003/02/20 19:44:06  dicuccio
 * Created new plugin architecture, mediated via an ASN.1 spec.  Moved GBENCH
 * framework over to use new plugin architecture.
 *
 * ===========================================================================
 */

#endif  // GUI_CORE___CONTEXT_FACTORY__HPP