Re: [boost] Is there any interest in a library which solves C++ class reflection feature just like Java does?

Subject: Re: [boost] Is there any interest in a library which solves C++ class reflection feature just like Java does?
From: jinhua luo (ljh.home.king_at_[hidden])
Date: 2011-12-06 22:59:20

Hi,

I'm preparing to publish this reflection project, e.g. figure out where to
host it, which may take some time. Meanwhile, I'm busy working on a SQL
mapping (similar to MyBatis) project which is based on this reflection
project.

Regards,
JinHua

2011/12/7 Hartmut Kaiser <hartmut.kaiser_at_[hidden]>

> > In brief, I'd designed and implemented somehow C++ class reflection based
> > on boost libraries.
> > It has some unique advantages:
> > a) it doesn't require code generator
> > b) platform independent and compiler independent (I tested it on Windows
> > and Linux, with vs2008 and gcc respectively)
> > c) it's non-intrusive for the class definition, instead, you just need to
> > declare and describe your class via some straightforward macros anywhere
> > (header file or source file, and may be within any namespace), which also
> > means you can wrap an external third-party library (which you have no way
> > to touch the source codes) and reflects it classes.
> > d) Cross shared library boundary, you can dynamic load the shared library
> > and reflect the classes within it, without need to export any symbol
> > manunally in C wrapper function way
> > e) the API looks like Java reflection API
>
> I'm interested, could we see the sources, please?
>
> Regards Hartmut
> ---------------
> http://boost-spirit.com
> http://stellar.cct.lsu.edu
>
>
> >
> > Below is some codes snippet to have an overview of this library:
> > -----libTest.cpp---start---
> > #include <iostream>
> > #include <string>
> >
> > #include <boost/reflection/reflection.hpp>
> >
> > namespace test {
> >
> > class AccountItf {
> > public:
> >     virtual std::string getId() const = 0;
> >     virtual void setId(std::string id) = 0; };
> >
> > #define ACCOUNT_INTERFACE_REFL_DECLARE \
> >     BOOST_REFL_INTERFACE(test::AccountItf) \
> >     BOOST_REFL_CONST_METHOD(getId, std::string()) \
> >     BOOST_REFL_METHOD(setId, void(std::string))
> >
> > class Account : public AccountItf {
> >     std::string id;
> > public:
> >     Account() : age(0) {}
> >     Account(std::string id, unsigned int age) : id(id), age(age) {}
> >     static void echo(Account* acct, std::string banner) {
> >         std::cout << banner + ": " << acct->getId() << std::endl;
> >     }
> >     std::string getId() const {
> >         return id;
> >     }
> >     void setId(std::string id) {
> >         this->id = id;
> >     }
> > public:
> >     unsigned int age;
> > };
> >
> > //Account declaration for used by reflection //this declaration can be
> > placed anywhere, even the header file BOOST_REFL_CLASS (
> >     (test)(Account),
> >     //constructors
> >     BOOST_REFL_CONSTRUCTOR()
> >     BOOST_REFL_CONSTRUCTOR(std::string id, unsigned int age)
> >     //static methods
> >     BOOST_REFL_STATIC_METHOD(echo, void (Account* acct, std::string
> > banner))
> >     //properties
> >     BOOST_REFL_PROPERTY(age, unsigned int)
> >     //derived Inteface
> >     ACCOUNT_INTERFACE_REFL_DECLARE
> > )
> > }
> >
> > -----libTest.cpp----end--
> > Compile the libTest.cpp into the libTest.dll or libTest.so.
> >
> > -----main.cpp----start--
> > #include <iostream>
> > #include <string>
> > using namespace std;
> >
> > #include <boost/reflection/reflection.hpp> using namespace
> > boost::reflection;
> >
> > #if defined(BOOST_WINDOWS)
> > #include <Windows.h>
> > #else
> > #include <dlfcn.h>
> > #endif
> >
> > int main(int argc, char* argv[])
> > {
> > #if defined(BOOST_WINDOWS)
> >     LoadLibraryA (argv[1]);
> > #else
> >     dlopen(argv[1], RTLD_NOW);
> > #endif
> >     Class t = Class::forName("test.Account");
> >
> >     boost::any obj = t.newInstance(std::string("Account-id-100"),
> > (unsigned int)26);
> >
> >     t.invokeStatic("echo", obj, std::string("TEST"));
> >
> >     TypeInfoArray tArray;
> >     tArray.push_back(BOOST_REFL_TYPEID(std::string));
> >     Method m1 = t.getMethod("setId", tArray);
> >     m1.invoke(obj, std::string("Account-id-200"));
> >
> >     Method m2 = t.getMethod("getId");
> >     boost::any ret = m2.invoke(obj);
> >     std::cout << "Account getId(): " << boost::any_cast<std::string>(ret)
> > << std::endl;
> >
> >     Property prop = t.getProperty("age");
> >     prop.set(obj, (unsigned int)30);
> >     std::cout << "Account age: " << boost::any_cast<unsigned
> > int>(prop.get(obj)) << std::endl;
> >
> >     return 0;
> > }
> > -----main.cpp---end---
> >
> > Compile the main.cpp into the executable and execute it:
> > ./main libTest.dll
> >
> > it will output:
> > TEST: Account-id-100
> > Account getId(): Account-id-200
> > Account age: 30
> >
> >
> > This library is very useful for framework-level design which needs C++
> > reflection, e.g. recently I'm working on somehow SQL mapping library for
> > C++, just like MyBatis, and reflection makes possible to invoke the
> > getter/setter of the object instances of classes specified in the XML
> > file.
> >
> > Regards,
> > JinHua
> >
> > _______________________________________________
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