nPersistServer Class Reference
[Nebula Kernel]

#include <npersistserver.h>

Inheritance diagram for nPersistServer:

List of all members.

Detailed Description

Interface to the file system for serializing objects.

Nebula Persistent Object File Format

The actual format of serialized objects is not specified. Instead script server objects are used to translate nCmd objects emitted by objects into actual script statements that will be saved to files. However, since the file server needs to know which script server to use for reading serialized object files, there has to be some meta information in the file itself which names the class of the script server which understands it.

Within the first 128 Bytes of a serialized object file the following string must be embedded:

    $parser:classname$

Where 'classname' is the script server's class which has to be used to read that file.

Folded and unfolded objects

Note:: UNFOLDED OBJECTS ARE NO LONGER SUPPORTED FOR WRITING, AND READING IS ONLY SUPPORTED FOR "FLAT" FILE HIERARCHIES (i.e. a "nKernelServer::Load("bla.n") is allowed if bla.n is a directory, and contains a _main file).

Serialized objects can be saved in 2 ways, folded and unfolded. Folded means, the object itself and all of it's children will be saved into a single file. Unfolded means that for each object, a directory will be create in the host filesystem, so that a saved object hierarchy will result in a corresponding directory hierarchy.

Code

The following code demonstrates how to specify nluaserver for persist server:

    nPersistServer* persisitServer;

    persisitServer = nKernelServer::Instance()->GetPersistServer();
    persisitServer->SetSaverClass("nluaserver");

Definition at line 71 of file npersistserver.h.


Public Types
enum	nSaveMode { SAVEMODE_FOLD, SAVEMODE_CLONE }
	Save modes. More...
Public Member Functions
	nPersistServer ()
	constructor
virtual	~nPersistServer ()
	destructor
void	SetSaveMode (nSaveMode)
	set the save mode
nSaveMode	GetSaveMode ()
	get the save mode
void	SetSaveLevel (int)
	set the save level
int	GetSaveLevel ()
	get the save level
bool	SetSaverClass (const nString &saverClass)
	set the script server class which should be used for saving
nString	GetSaverClass ()
	get the script server class which is currently used for saving
bool	BeginObject (nObject obj, const char name, bool isObjNamed)
	begin a persistent object
bool	BeginObjectWithCmd (nRoot obj, nCmd cmd, const char *name)
	begin a persistent object with constructor command
nCmd *	GetCmd (nObject *obj, nFourCC id)
	create a nCmd object
bool	PutCmd (nCmd *cmd)
	put a cmd into persistency stream
bool	PutCmd (int level, nCmd *cmd)
	put a cmd into persistency stream if savelevel permits
bool	EndObject (bool isObjNamed)
	finish a persistent object
nObject *	GetClone ()
	return cloned object
nObject *	LoadObject (const char fileName, const char objName)
	load a object from persistency stream

Member Enumeration Documentation

enum nPersistServer::nSaveMode

Save modes.

Enumerator:

SAVEMODE_FOLD
SAVEMODE_CLONE	default mode

Definition at line 75 of file npersistserver.h.

Constructor & Destructor Documentation

nPersistServer::nPersistServer

(

)

constructor

Definition at line 14 of file npersistserver_main.cc.

nPersistServer::~nPersistServer ( ) [virtual]

destructor

Definition at line 28 of file npersistserver_main.cc.

Member Function Documentation

void nPersistServer::SetSaveMode

(

nSaveMode

)

set the save mode

nPersistServer::nSaveMode nPersistServer::GetSaveMode

(

)

get the save mode

05-Nov-98 floh created

Definition at line 301 of file npersistserver_main.cc.

void nPersistServer::SetSaveLevel

(

int

)

set the save level

Definition at line 37 of file npersistserver_main.cc.

int nPersistServer::GetSaveLevel

(

)

get the save level

Definition at line 46 of file npersistserver_main.cc.

bool nPersistServer::SetSaverClass

(

const nString &

saverClass

)

set the script server class which should be used for saving

Set class of script server which should be used to save objects. Creates a local script server object if not exists.

Parameters:

saverClass

name of a nScriptServer derived class

Returns:: currently always true, breaks if object could not be created

Definition at line 60 of file npersistserver_main.cc.

nString nPersistServer::GetSaverClass

(

)

get the script server class which is currently used for saving

Get name of class which is currently used to save objects.

Definition at line 93 of file npersistserver_main.cc.

bool nPersistServer::BeginObject	(	nObject *	obj,
		const char *	name,
		bool	isObjNamed
	)

begin a persistent object

04-Nov-98 floh created
05-Nov-98 floh autonome Objects gekillt
18-Dec-98 floh + SAVEMODE_CLONE
09-Nov-04 enlight + nObject support

Definition at line 141 of file npersistserver_main.cc.

bool nPersistServer::BeginObjectWithCmd	(	nRoot *	obj,
		nCmd *	cmd,
		const char *	name
	)

begin a persistent object with constructor command

Start writing object, with constructor cmd instead of a generic "new [class] [name]". If cmd pointer is NULL, no constructor statement will be written, just the select statement.

29-Feb-00 floh created

Definition at line 166 of file npersistserver_main.cc.

nCmd * nPersistServer::GetCmd	(	nObject *	obj,
		nFourCC	id
	)

create a nCmd object

04-Nov-98 floh created
19-Dec-98 floh neues Arg, id + jetzt doch etwas komplexer, sucht das Command selbst raus, indem es die Klassen des Objekts durchsucht
08-Aug-99 floh + benutzt nicht mehr nCmdProto::GetCmd(), sondern nCmdProto::NewCmd()

Definition at line 220 of file npersistserver_main.cc.

bool nPersistServer::PutCmd

(

nCmd *

cmd

)

put a cmd into persistency stream

This is the same as a PutCmd(0,cmd).

04-Nov-98 floh created
08-Aug-99 floh nCmd wird nicht mehr per delete(), sondern per Cmd-Proto freigegeben
20-Jan-00 floh rewritten to ref_ss

Definition at line 281 of file npersistserver_main.cc.

bool nPersistServer::PutCmd	(	int	level,
		nCmd *	cmd
	)

put a cmd into persistency stream if savelevel permits

Ignore if level is less or equal the internal save level defined by 'SetSaveLevel'.

16-Jun-00 floh created

Definition at line 250 of file npersistserver_main.cc.

bool nPersistServer::EndObject

(

bool

isObjNamed

)

finish a persistent object

04-Nov-98 floh created
05-Nov-98 floh autonome Objects gekillt
18-Dec-98 floh + SAVEMODE_CLONE
09-Nov-04 enlight + nObject support

Definition at line 194 of file npersistserver_main.cc.

nObject * nPersistServer::GetClone

(

)

return cloned object

Get the pointer to the cloned object.

18-Dec-98 floh created
08-Nov-04 enlight now returns nObject* instead of nRoot*

Definition at line 260 of file npersistserver_beginend.cc.

nObject * nPersistServer::LoadObject	(	const char *	fileName,
		const char *	objName
	)

load a object from persistency stream

Definition at line 160 of file npersistserver_load.cc.

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

Documentation

Links

nPersistServer Class Reference [Nebula Kernel]