coherence/lang/cloneable_spec.hpp

/*
* cloneable_spec.hpp
*
* Copyright 2001-2008 by Oracle. All rights reserved.
*
* Oracle is a registered trademarks of Oracle Corporation and/or its
* affiliates.
*
* This software is the confidential and proprietary information of Oracle
* Corporation. You shall not disclose such confidential and proprietary
* information and shall use it only in accordance with the terms of the
* license agreement you entered into with Oracle.
*
* This notice may not be removed or altered.
*/
#ifndef COH_CLONEABLE_SPEC_HPP
#define COH_CLONEABLE_SPEC_HPP

#include "coherence/lang/compatibility.hpp"

#include "coherence/lang/class_spec.hpp"
#include "coherence/lang/lang_spec.hpp"
#include "coherence/lang/TypedHandle.hpp"
#include "coherence/lang/TypedHolder.hpp"

COH_OPEN_NAMESPACE2(coherence,lang)

class Object;

/**
* Helper for defining a cloneable managed class.
*
* It addition to the features auto-generated by the class_spec<> helper template
* cloneable_spec<> auto-generates an implemenation of "Object::Handle clone() const"
* which delegates to the defined classes const copy constructor.
*
* A normal cloneable class defintion would be:
* @code
* class Foo
*   : public cloneable_spec<Foo,
*       extends<Bar>,
*       implements<SomeInterface, SomeOtherInterface> >
*   {
*   // add support for auto-generated static create methods
*   friend class factory<Foo>;
*
*   protected:
*       // Constructors are defined as protected, and access via
*       // auto-generated create methods, with matching signatures
*       Foo()
*           : super() ...
*           {
*           }
*
*       // Copy constructor
*       Foo(const Foo& that)
*           : super(that) ...
*           {
*           }
*
*   public:
*       // normal class definition....
*   };
* @endcode
*
* @see extends
* @see implements
*
* @author mf 2008.07.14
*/
template<class T, class E = extends<Object>, class I = implements<> >
class COH_EXPORT_SPEC cloneable_spec
    : public class_spec<T, E, I>
    {
    // ----- typedefs -------------------------------------------------------

    public:
        /**
        * Specification definition
        */
        typedef cloneable_spec this_spec;

        /**
        * Definition T's parent class
        */
        typedef cloneable_spec super;

    // ----- constructors ---------------------------------------------------

    protected:
        /**
        * Generate a set of proxy constuctors matching the signatures of the
        * parent class's constructors.
        *
        * NOTE: Compilation errors referencing this line likely indicate that
        *       class being defined by this spec makes calls a "super"
        *       constructor supplying a set of parameters for which there is
        *       no exact match on the parent class.
        */
        COH_DECLARE_PROXY_CONSTRUCTORS(cloneable_spec);

    public:
        /**
        * @inheritDoc
        */
        virtual TypedHandle<Object> clone() const
            {
            try
                {
                return create(dynamic_cast<const T&>(*this));
                }
            catch (...)
                {
                // The above cast should never fail, but in MSVC 2005 it did when
                // this clone implmentation was used for coherence::lang::String.
                // String has manually implemented clone() to get around the
                // issue, but this handler is left in place to catch other
                // occurances. String is a rather special type of class
                // definition as it uses protected inheirtance from Array<char>
                // this may have triggered the compiler issue.
                std::cerr << "Coherence: unexpected error casting from \""
                    << typeid(*this).name() << "\" to \"" << typeid(const T).name()
                    << "\" type equality == " << (typeid(const T) == typeid(*this))
                    << std::endl;
                throw;
                }
            }
    };
COH_DEFINE_PROXY_CONSTRUCTORS(COH_TEMPLATE_DECLARE3(T, E, I), \
        COH_TEMPLATE_DEFINE3(T, E, I), cloneable_spec, \
        class_spec COH_TEMPLATE_DEFINE3(T, E, I))

COH_CLOSE_NAMESPACE2

#endif // COH_CLONEABLE_SPEC_HPP

Copyright (c) 2000-2008 Oracle. All rights reserved.