ROOT » CORE » BASE » TPluginHandler

class TPluginHandler: public TObject


This class implements a plugin library manager. It keeps track of
a list of plugin handlers. A plugin handler knows which plugin
library to load to get a specific class that is used to extend the
functionality of a specific base class and how to create an object
of this class. For example, to extend the base class TFile to be
able to read RFIO files one needs to load the plugin library which defines the TRFIOFile class. This loading should
be triggered when a given URI contains a regular expression defined
by the handler.
Plugin handlers can be defined via macros in a list of plugin
directories. With $ROOTSYS/etc/plugins the default top plugin
directory specified in $ROOTSYS/etc/system.rootrc. Additional
directories can be specified by adding them to the end of the list.
Macros for identical plugin handlers in later directories will
override previous ones (the inverse of normal search path behavior).
The macros must have names like <BaseClass>/PX0_<PluginClass>.C,
TFile/P10_TRFIOFile.C, TSQLServer/P20_TMySQLServer.C, etc.
to allow easy sorting and grouping. If the BaseClass is in a
namespace the directory must have the name NameSpace@@BaseClass as
: is a reserved pathname character on some operating systems.
Macros not beginning with 'P' and ending with ".C" are ignored.
These macros typically look like:

void P10_TDCacheFile()
gPluginMgr->AddHandler("TFile", "^dcache", "TDCacheFile",
"DCache", "TDCacheFile(const char*,Option_t*)");

Plugin handlers can also be defined via resources in the .rootrc
file. Although now deprecated this method still works for backward
compatibility, e.g.:

Plugin.TFile:       ^rfio:   TRFIOFile    RFIO   "<constructor>"
Plugin.TSQLServer:  ^mysql:  TMySQLServer MySQL  "<constructor>"
+Plugin.TSQLServer: ^pgsql:  TPgSQLServer PgSQL  "<constructor>"
Plugin.TVirtualFitter: *     TFitter      Minuit "TFitter(Int_t)"

Where the + in front of Plugin.TSQLServer says that it extends the
existing definition of TSQLServer, useful when there is more than
one plugin that can extend the same base class. The "<constructor>"
should be the constructor or a static method that generates an
instance of the specified class. Global methods should start with
"::" in their name, like "::CreateFitter()".
Instead of being a shared library a plugin can also be a CINT
script, so instead of one can have Dialog.C.
The * is a placeholder in case there is no need for a URI to
differentiate between different plugins for the same base class.
For the default plugins see $ROOTSYS/etc/system.rootrc.

Plugin handlers can also be registered at run time, e.g.:

gPluginMgr->AddHandler("TSQLServer", "^sapdb:",
"TSapDBServer", "SapDB",
"TSapDBServer(const char*,const char*, const char*)");

A list of currently defined handlers can be printed using:

gPluginMgr->Print(); // use option="a" to see ctors

The use of the plugin library manager removes all textual references
to hard-coded class and library names and the resulting dependencies
in the base classes. The plugin manager is used to extend a.o.
TFile, TSQLServer, TGrid, etc. functionality.

Function Members (Methods)

voidTObject::AbstractMethod(const char* method) const
virtual voidTObject::AppendPad(Option_t* option = "")
virtual voidTObject::Browse(TBrowser* b)
Int_tCheckPlugin() const
static TClass*Class()
virtual const char*TObject::ClassName() const
virtual voidTObject::Clear(Option_t* = "")
virtual TObject*TObject::Clone(const char* newname = "") const
virtual Int_tTObject::Compare(const TObject* obj) const
virtual voidTObject::Copy(TObject& object) const
virtual voidTObject::Delete(Option_t* option = "")MENU
virtual Int_tTObject::DistancetoPrimitive(Int_t px, Int_t py)
virtual voidTObject::Draw(Option_t* option = "")
virtual voidTObject::DrawClass() constMENU
virtual TObject*TObject::DrawClone(Option_t* option = "") constMENU
virtual voidTObject::Dump() constMENU
virtual voidTObject::Error(const char* method, const char* msgfmt) const
Long_tExecPlugin<>(int nargs)
virtual voidTObject::Execute(const char* method, const char* params, Int_t* error = 0)
virtual voidTObject::Execute(TMethod* method, TObjArray* params, Int_t* error = 0)
virtual voidTObject::ExecuteEvent(Int_t event, Int_t px, Int_t py)
virtual voidTObject::Fatal(const char* method, const char* msgfmt) const
virtual TObject*TObject::FindObject(const char* name) const
virtual TObject*TObject::FindObject(const TObject* obj) const
const char*GetClass() const
virtual Option_t*TObject::GetDrawOption() const
static Long_tTObject::GetDtorOnly()
virtual const char*TObject::GetIconName() const
virtual const char*TObject::GetName() const
virtual char*TObject::GetObjectInfo(Int_t px, Int_t py) const
static Bool_tTObject::GetObjectStat()
virtual Option_t*TObject::GetOption() const
virtual const char*TObject::GetTitle() const
virtual UInt_tTObject::GetUniqueID() const
virtual Bool_tTObject::HandleTimer(TTimer* timer)
virtual ULong_tTObject::Hash() const
virtual voidTObject::Info(const char* method, const char* msgfmt) const
virtual Bool_tTObject::InheritsFrom(const char* classname) const
virtual Bool_tTObject::InheritsFrom(const TClass* cl) const
virtual voidTObject::Inspect() constMENU
voidTObject::InvertBit(UInt_t f)
virtual TClass*IsA() const
virtual Bool_tTObject::IsEqual(const TObject* obj) const
virtual Bool_tTObject::IsFolder() const
Bool_tTObject::IsOnHeap() const
virtual Bool_tTObject::IsSortable() const
Bool_tTObject::IsZombie() const
virtual voidTObject::ls(Option_t* option = "") const
voidTObject::MayNotUse(const char* method) const
virtual Bool_tTObject::Notify()
voidTObject::Obsolete(const char* method, const char* asOfVers, const char* removedFromVers) const
voidTObject::operator delete(void* ptr)
voidTObject::operator delete(void* ptr, void* vp)
voidTObject::operator delete[](void* ptr)
voidTObject::operator delete[](void* ptr, void* vp)
void*TObject::operator new(size_t sz)
void*TObject::operator new(size_t sz, void* vp)
void*TObject::operator new[](size_t sz)
void*TObject::operator new[](size_t sz, void* vp)
virtual voidTObject::Paint(Option_t* option = "")
virtual voidTObject::Pop()
virtual voidPrint(Option_t* opt = "") const
virtual Int_tTObject::Read(const char* name)
virtual voidTObject::RecursiveRemove(TObject* obj)
voidTObject::ResetBit(UInt_t f)
virtual voidTObject::SaveAs(const char* filename = "", Option_t* option = "") constMENU
virtual voidTObject::SavePrimitive(ostream& out, Option_t* option = "")
voidTObject::SetBit(UInt_t f)
voidTObject::SetBit(UInt_t f, Bool_t set)
virtual voidTObject::SetDrawOption(Option_t* option = "")MENU
static voidTObject::SetDtorOnly(void* obj)
static voidTObject::SetObjectStat(Bool_t stat)
virtual voidTObject::SetUniqueID(UInt_t uid)
virtual voidShowMembers(TMemberInspector& insp) const
virtual voidStreamer(TBuffer&)
voidStreamerNVirtual(TBuffer& ClassDef_StreamerNVirtual_b)
virtual voidTObject::SysError(const char* method, const char* msgfmt) const
Bool_tTObject::TestBit(UInt_t f) const
Int_tTObject::TestBits(UInt_t f) const
virtual voidTObject::UseCurrentStyle()
virtual voidTObject::Warning(const char* method, const char* msgfmt) const
virtual Int_tTObject::Write(const char* name = 0, Int_t option = 0, Int_t bufsize = 0)
virtual Int_tTObject::Write(const char* name = 0, Int_t option = 0, Int_t bufsize = 0) const
virtual voidTObject::DoError(int level, const char* location, const char* fmt, va_list va) const
Bool_tCanHandle(const char* base, const char* uri)
Bool_tCheckForExecPlugin(Int_t nargs)
const char*GetBase() const
const char*GetCtor() const
const char*GetOrigin() const
const char*GetPlugin() const
const char*GetRegexp() const
TPluginHandler&operator=(const TPluginHandler&)
TPluginHandler(const TPluginHandler&)
TPluginHandler(const char* base, const char* regexp, const char* className, const char* pluginName, const char* ctor, const char* origin)

Data Members

static TObject::(anonymous)TObject::kBitMask
static TObject::EStatusBitsTObject::kCanDelete
static TObject::EStatusBitsTObject::kCannotPick
static TObject::EStatusBitsTObject::kHasUUID
static TObject::EStatusBitsTObject::kInvalidObject
static TObject::(anonymous)TObject::kIsOnHeap
static TObject::EStatusBitsTObject::kIsReferenced
static TObject::EStatusBitsTObject::kMustCleanup
static TObject::EStatusBitsTObject::kNoContextMenu
static TObject::(anonymous)TObject::kNotDeleted
static TObject::EStatusBitsTObject::kObjInCanvas
static TObject::(anonymous)TObject::kOverwrite
static TObject::(anonymous)TObject::kSingleKey
static TObject::(anonymous)TObject::kWriteDelete
static TObject::(anonymous)TObject::kZombie
TStringfBasebase class which will be extended by plugin
TMethodCall*fCallEnv!ctor method call environment
Int_tfCanCall!if 1 fCallEnv is ok, -1 fCallEnv is not ok
TStringfClassclass to be loaded from plugin library
TStringfCtorctor used to instantiate object of fClass
Bool_tfIsGlobalplugin ctor is a global function
Bool_tfIsMacroplugin is a macro and not a library
TFunction*fMethod!ctor method or global function
TStringfOriginorigin of plugin handler definition
TStringfPluginplugin library which should contain fClass
TStringfRegexpregular expression which must be matched in URI

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

TPluginHandler(const char* base, const char* regexp, const char* className, const char* pluginName, const char* ctor, const char* origin)
 Create a plugin handler. Called by TPluginManager.
 Cleanup plugin handler object.
Bool_t CanHandle(const char* base, const char* uri)
 Check if regular expression appears in the URI, if so return kTRUE.
 If URI = 0 always return kTRUE.
void SetupCallEnv()
 Setup ctor or static method call environment.
Int_t CheckPlugin() const
 Check if the plugin library for this handler exits. Returns 0
 when it exists and -1 in case the plugin does not exist.
Int_t LoadPlugin()
 Load the plugin library for this handler. Returns 0 on successful loading
 and -1 in case the library does not exist or in case of error.
Bool_t CheckForExecPlugin(Int_t nargs)
 Check that we can properly run ExecPlugin.
void Print(Option_t* opt = "") const
 Print info about the plugin handler. If option is "a" print
 also the ctor's that will be used.
{ }
TPluginHandler(const char* base, const char* regexp, const char* className, const char* pluginName, const char* ctor, const char* origin)
TPluginHandler& operator=(const TPluginHandler& )
const char * GetBase() const
{ return fBase; }
const char * GetRegexp() const
{ return fRegexp; }
const char * GetPlugin() const
{ return fPlugin; }
const char * GetCtor() const
{ return fCtor; }
const char * GetOrigin() const
{ return fOrigin; }
const char * GetClass() const
{ return fClass; }