DOMable.h File Reference

#include <nidas/util/InvalidParameterException.h>
#include "DOMObjectFactory.h"
#include "XDOM.h"
#include "XMLStringConverter.h"
#include <xercesc/util/XMLUniDefs.hpp>
#include <xercesc/util/XMLString.hpp>
#include <xercesc/dom/DOMDocument.hpp>
#include <xercesc/dom/DOMNode.hpp>
#include <xercesc/dom/DOMElement.hpp>
#include <xercesc/dom/DOMException.hpp>
#include <xercesc/dom/DOMNamedNodeMap.hpp>

Go to the source code of this file.

Classes
class	nidas::core::DOMable
	Interface of an object that can be instantiated from a DOM element, via the fromDOMElement method, or that can be serialized into a DOM, via the toDOMParent/toDOMElement method. More...

Namespaces
namespace	nidas
	Root namespace for the NCAR In-Situ Data Acquisition Software.
namespace	nidas::core
	The essential core classes of nidas.

Macros
#define	NIDAS_CREATOR_FUNCTION(CLASSNAME)
	Define a "creator" function, an extern "C" function that invokes a public no-arg constructor for a class.
#define	NIDAS_CREATOR_FUNCTION_NS(NS, CLASSNAME)
	Same as NIDAS_CREATOR_FUNCTION(CLASSNAME), but with a namespace argument, indicating a namespace under nidas::dynld.

Macro Definition Documentation

NIDAS_CREATOR_FUNCTION

#define NIDAS_CREATOR_FUNCTION

(

CLASSNAME

)

Value:

extern "C" {\
    nidas::core::DOMable* create_nidas_dynld_##CLASSNAME()\
    {\
    return new nidas::dynld::CLASSNAME();\
    }\
}

Define a "creator" function, an extern "C" function that invokes a public no-arg constructor for a class.

Parameters

CLASSNAME

Name of class, without quotes.

The idea here is to define a function that we can lookup by name with DynamicLoader::lookup(string). Since we don't want to know how C++ mangles namespace names, this C function must not be in a namespace. The class is in a namespace though, so we do our own crude name mangling in order to keep creator functions for separate namespaces distinct, by substituting underscores for "::".

Example: nidas::dynld::MyClass is derived from nidas::core::DOMable so that a pointer to DOMable can be returned by DOMObjectFactory::createObject("MyClass"):

namespace nidas { namespace dynld { class MyClass : public nidas::core::DOMable { public: MyClass() { ... } // no-arg ctor }; }}

Define an extern "C" creator function:

NIDAS_CREATOR_FUNCTION(MyClass)

This defines a C function called create_nidas_dynld_MyClass() which invokes the nidas::dynld::MyClass() no arg constructor.

To create a pointer to a new instance of nidas::dynld::MyClass from a name in a string, do:

DOMable* newobj = DOMObjectFactory::createObject("MyClass");

Then one can cast it to a pointer to MyClass:

nidas::dynld::MyClass* classobj = dynamic_cast<nidas::dynld::MyClass*>(newobj);

DOMObjectFactory::createObject does the name mangling by prepending "create_nidas_dynld_" to the string argument, converting all "::" to '_' in the class name string and then does a lookup:

nidas::core::DOMable* (*ctor)() = DynamicLoader::lookup("create_nidas_dynld_MyClass");

Then it executes the creator function to get a pointer to the object:

nidas::core::DOMable* obj = ctor();

NIDAS_CREATOR_FUNCTION_NS

#define NIDAS_CREATOR_FUNCTION_NS	(		NS,
			CLASSNAME )

Value:

extern "C" {\
    nidas::core::DOMable* create_nidas_dynld_##NS##_##CLASSNAME()\
    {\
    return new nidas::dynld::NS::CLASSNAME();\
    }\
}

Same as NIDAS_CREATOR_FUNCTION(CLASSNAME), but with a namespace argument, indicating a namespace under nidas::dynld.

Parameters

NS	namespace of class.
CLASSNAME	Name of class.