vsl_binary_loader< BaseClass > Class Template Reference

Class to load objects by baseclass pointer. More...

#include <vsl_binary_loader.h>

Inheritance diagram for vsl_binary_loader< BaseClass >:

Public Member Functions
	vsl_binary_loader ()=default
	Constructor. More...
	~vsl_binary_loader () override
	Destructor. More...
void	make_empty ()
	Remove all example objects. More...
void	add (const BaseClass &b)
	Add example object to list of those that can be loaded. More...
const std::vector< BaseClass * > &	object ()
	Return current list of class objects which can be loaded. More...
void	load_object (vsl_b_istream &is, BaseClass *&b)
	Loads object and sets base class pointer. More...
std::string	is_a () const

Static Public Member Functions
static vsl_binary_loader< BaseClass > &	instance ()
	Returns the instance variable for the singleton. More...

Protected Member Functions
void	register_this ()
	Register this, so it can be deleted by vsl_delete_all_loaders();. More...

Private Attributes
std::vector< BaseClass * >	object_
	List of concrete classes that this loader can deal with. More...

Static Private Attributes
static vsl_binary_loader< BaseClass > *	instance_ = nullptr
	the singleton object. More...

Detailed Description

template<class BaseClass>
class vsl_binary_loader< BaseClass >

Class to load objects by baseclass pointer.

An example of a singleton design pattern for loading a DerivedClass from a stream into a BaseClass*. All we are given is a BaseClass* into which the object has to be loaded but we can only tell what sort of object it is from the is_a() information stored in the stream. To handle this we define a loader which has a list of BaseClass pointers, and the ChainOfResponsibility (Design Pattern) approach is used to load the object i.e. each ptr->is_a() is matched against the string on the stream until we find a match or run out of pointers. If a pointer is found which matches the string on the stream, we clone it, use the clone to load the object from the stream, then return a pointer to the clone.

We use a singleton so that there is only one list of concrete derived classes which can be added to for loading purposes. If you derive a new class you just have to append it to the list of classes of the singleton, viz: vsl_binary_loader::instance().append(my_object) The BaseClass MUST implement is_a(),is_class(),clone(),b_write() and b_read() virtual functions.

vsl_binary_loader.h also provides the function templates for loading and saving by base class pointer

All loader singletons can be deleted using vsl_delete_all_loaders()

Definition at line 49 of file vsl_binary_loader.h.

Constructor & Destructor Documentation

vsl_binary_loader()

template<class BaseClass>

vsl_binary_loader< BaseClass >::vsl_binary_loader ( )

default

Constructor.

~vsl_binary_loader()

template<class BaseClass >

vsl_binary_loader< BaseClass >::~vsl_binary_loader ( )

override

Destructor.

Definition at line 36 of file vsl_binary_loader.hxx.

Member Function Documentation

add()

template<class BaseClass>

void vsl_binary_loader< BaseClass >::add ( const BaseClass &  b )

inline

Add example object to list of those that can be loaded.

Definition at line 71 of file vsl_binary_loader.h.

instance()

template<class BaseClass >

vsl_binary_loader< BaseClass > & vsl_binary_loader< BaseClass >::instance ( )

static

Returns the instance variable for the singleton.

Definition at line 15 of file vsl_binary_loader.hxx.

is_a()

template<class BaseClass>

std::string vsl_binary_loader< BaseClass >::is_a

(

)

const

load_object()

template<class BaseClass >

void vsl_binary_loader< BaseClass >::load_object	(	vsl_b_istream &	is,
		BaseClass *&	b
	)

Loads object and sets base class pointer.

Determines which derived class object on is belongs to, loads it and sets b to be a pointer to it. (Class must be one given to Loader by the add method). If is indicates a NULL pointer, b will be set to NULL. If b not initially NULL, *b will be deleted.

Definition at line 44 of file vsl_binary_loader.hxx.

make_empty()

template<class BaseClass >

void vsl_binary_loader< BaseClass >::make_empty

(

)

Remove all example objects.

Definition at line 28 of file vsl_binary_loader.hxx.

object()

template<class BaseClass>

const std::vector<BaseClass*>& vsl_binary_loader< BaseClass >::object ( )

inline

Return current list of class objects which can be loaded.

Definition at line 74 of file vsl_binary_loader.h.

register_this()

void vsl_binary_loader_base::register_this ( )

protectedinherited

Register this, so it can be deleted by vsl_delete_all_loaders();.

Definition at line 37 of file vsl_binary_loader_base.cxx.

Member Data Documentation

instance_

template<class BaseClass>

vsl_binary_loader< BaseClass > * vsl_binary_loader< BaseClass >::instance_ = nullptr

staticprivate

the singleton object.

Definition at line 52 of file vsl_binary_loader.h.

object_

template<class BaseClass>

std::vector<BaseClass*> vsl_binary_loader< BaseClass >::object_

private

List of concrete classes that this loader can deal with.

Definition at line 55 of file vsl_binary_loader.h.

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The documentation for this class was generated from the following files:

• core/vsl/vsl_binary_loader.h
• core/vsl/vsl_binary_loader.hxx