The Command design pattern is based on the idea, that all editing in an application is done by creating instances of command objects.

Command objects apply changes to the edited object and then are stored on a command stack. Furthermore, each command knows how to undo its changes to bring the edited object back to its previous state. As long as the application only uses command objects to change the state of the edited object, it is possible to undo a sequence of commands by traversing the command stack downwards and calling the "undo" method of each command in turn. It is also possible to redo a sequence of commands by traversing the command stack upwards and calling the "redo" method of each command.

Examples:

Create a new command
TQCommand *com = new TQCommand("TH1", hpx, "SetFillColor(Color_t)"

"SetFillColor(Color_t)");

TQCommand
The Command design pattern is based on the idea, that all editing in an application is done by creati...
Definition TQCommand.h:27
- 1st parameter - the name of class
- 2nd parameter - object
- 3rd parameter - the name of do/redo method
- 4th parameter - the name of undo method Since redo,undo methods are the same, undo name can be omitted, e.g.
  TQCommand *com = new TQCommand("TH1", hpx, "SetFillColor(Color_t)");
  
  For objects derived from TObject class name can be omitted, e.g.
  TQCommand *com = new TQCommand(hpx, "SetFillColor(Color_t)");
Setting undo, redo parameters.
Color_t old_color = hpx->GetFillColor();

Color_t new_color = 4; // blue color

com->SetRedoArgs(1, new_color);

com->SetUndoArgs(1, old_color);

Color_t
short Color_t
Definition RtypesCore.h:92

TQCommand::SetRedoArgs
virtual void SetRedoArgs(Int_t nargs,...)
Set redo parameters.
Definition TQCommand.cxx:508

TQCommand::SetUndoArgs
virtual void SetUndoArgs(Int_t nargs,...)
Set undo parameters.
Definition TQCommand.cxx:542

1st argument - the number of undo, redo parameters the other arguments - undo, redo values Since the number of undo,redo parameters is the same one can use
com->SetArgs(1, new_color, old_color);

TQCommand::SetArgs
virtual void SetArgs(Int_t nargs,...)
Set do/redo and undo parameters.
Definition TQCommand.cxx:465
Undo, redo method execution
com->Redo(); // execute redo method

com->Undo(); // execute undo method

TQCommand::Undo
virtual void Undo(Option_t *option="")
Un-execute all merged commands and the command.
Definition TQCommand.cxx:626

TQCommand::Redo
virtual void Redo(Option_t *option="")
Execute command and then merge commands.
Definition TQCommand.cxx:588
Merged commands It possible to group several commands together so an end user can undo and redo them with one command.
TQCommand *update = new TQCommand(gPad, "Modified()");

com->Add(update);

update
static void update(gsl_integration_workspace *workspace, double a1, double b1, double area1, double error1, double a2, double b2, double area2, double error2)
Definition RooAdaptiveGaussKronrodIntegrator1D.cxx:652

gPad
#define gPad
Definition TVirtualPad.h:288

TQCommand::Add
virtual void Add(TObject *obj, Option_t *opt)
Add command to the list of merged commands.
Definition TQCommand.cxx:360
Macro commands "Merging" allows to create macro commands, e.g.
TQCommand *macro = new TQCommand("my macro");

macro->Add(com1);

macro->Add(com2);

...

During Redo operation commands composing macro command are executed sequentially in direct order (first in first out). During Undo, they are executed in reverse order (last in first out).
Undo manager. TQUndoManager is recorder of undo and redo operations. This is command history list which can be traversed backwards and upwards performing undo and redo operations. To register command TQUndoManager::Add(TObject*) method is used.
TQUndoManager *history = new TQUndoManager();

history->Add(com);

TQCommand::TQUndoManager
friend class TQUndoManager
Definition TQCommand.h:29

TQUndoManager
Recorder of operations for undo and redo.
Definition TQCommand.h:103

TQUndoManager::Add
virtual void Add(TObject *obj, Option_t *opt)
Add command to the stack of commands.
Definition TQCommand.cxx:959

TQUndoManager::Add automatically invokes execution of command's Redo method.

Use TQUndoManager::Undo to undo commands in history list. Redo is Undo for undo action. Use TQUndoManager::Redo method for that

Definition at line 27 of file TQCommand.h.

Public Member Functions
	TQCommand (const char cl=0, void object=0, const char redo=0, const char undo=0)
	Constructor.

	TQCommand (const TQCommand &com)
	Copy constructor.

	TQCommand (TObject obj, const char redo=0, const char *undo=0)
	Constructor.

virtual	~TQCommand ()
	dtor.

virtual void	Add (TObject *obj)

virtual void	Add (TObject obj, Option_t opt)
	Add command to the list of merged commands.

virtual Bool_t	CanCompress (TQCommand *c) const
	By default, commands can be compressed if they are:

virtual Bool_t	CanMerge (TQCommand *c) const
	Two commands can be merged if they can be composed into a single command (Macro command).

virtual Bool_t	CanRedo () const
	Returns kTRUE if Redo action is possible, kFALSE if it's not.

virtual Bool_t	CanUndo () const
	Returns kTRUE if Undo action is possible, kFALSE if it's not.

virtual void	Compress (TQCommand *c)
	Compress command.

virtual void	Delete (Option_t *option="")
	If "opt" is not zero delete every merged command which option string is equal to "opt".

virtual const char *	GetName () const
	Returns the command name.

Int_t	GetNRargs () const
	Returns a number of redo arguments.

Int_t	GetNUargs () const
	Returns a number of undo arguments.

void *	GetObject () const
	Returns an object for which undo redo actions are applied.

TQConnection *	GetRedo () const

Long_t *	GetRedoArgs () const
	Returns a pointer to array of redo arguments.

const char *	GetRedoName () const
	Returns the name of redo command.

Int_t	GetStatus () const
	Returns a number of sequential undo or redo operations.

virtual const char *	GetTitle () const
	Returns command description.

TQConnection *	GetUndo () const

Long_t *	GetUndoArgs () const
	Returns a pointer to array of undo arguments.

const char *	GetUndoName () const
	Returns the name of undo command.

virtual Bool_t	IsEqual (const TObject *obj) const
	Equal comparison.

Bool_t	IsExecuting () const
	Returns kTRUE if command execution is in progress.

Bool_t	IsMacro () const
	Returns kTRUE if neither redo nor undo action specified.

Bool_t	IsRedoing () const
	Redo action is in progress.

virtual Bool_t	IsSetter () const
	Returns kTRUE is command if Redo is the same as Undo function and is the setter action.

Bool_t	IsUndoing () const
	Undo action is in progress.

virtual void	ls (Option_t *option="") const
	ls this command and merged commands

virtual Long64_t	Merge (TCollection , TFileMergeInfo )
	Merge a collection of TQCommand.

virtual void	Merge (TQCommand *c)
	Add command to the list of merged commands.

virtual void	Redo (Option_t *option="")
	Execute command and then merge commands.

virtual void	SetArgs (Int_t nargs,...)
	Set do/redo and undo parameters.

virtual void	SetName (const char *name)
	Sets name of the command.

virtual void	SetRedoArgs (Int_t nargs,...)
	Set redo parameters.

virtual void	SetTitle (const char *title)
	Sets description of the command.

virtual void	SetUndoArgs (Int_t nargs,...)
	Set undo parameters.

virtual void	Undo (Option_t *option="")
	Un-execute all merged commands and the command.

Public Member Functions inherited from TList
	TList ()

	TList (TObject *)

virtual	~TList ()
	Delete the list.

virtual void	AddAfter (const TObject after, TObject obj)
	Insert object after object after in the list.

virtual void	AddAfter (TObjLink after, TObject obj)
	Insert object after the specified ObjLink object.

virtual void	AddAt (TObject *obj, Int_t idx)
	Insert object at position idx in the list.

virtual void	AddBefore (const TObject before, TObject obj)
	Insert object before object before in the list.

virtual void	AddBefore (TObjLink before, TObject obj)
	Insert object before the specified ObjLink object.

virtual void	AddFirst (TObject *obj)
	Add object at the beginning of the list.

virtual void	AddFirst (TObject obj, Option_t opt)
	Add object at the beginning of the list and also store option.

virtual void	AddLast (TObject *obj)
	Add object at the end of the list.

virtual void	AddLast (TObject obj, Option_t opt)
	Add object at the end of the list and also store option.

virtual TObject *	After (const TObject *obj) const
	Returns the object after object obj.

virtual TObject *	At (Int_t idx) const
	Returns the object at position idx. Returns 0 if idx is out of range.

virtual TObject *	Before (const TObject *obj) const
	Returns the object before object obj.

virtual void	Clear (Option_t *option="")
	Remove all objects from the list.

virtual TObject *	FindObject (const char *name) const
	Find an object in this list using its name.

virtual TObject *	FindObject (const TObject *obj) const
	Find an object in this list using the object's IsEqual() member function.

virtual TObject *	First () const
	Return the first object in the list. Returns 0 when list is empty.

virtual TObjLink *	FirstLink () const

virtual TObject **	GetObjectRef (const TObject *obj) const
	Return address of pointer to obj.

Bool_t	IsAscending ()

virtual TObject *	Last () const
	Return the last object in the list. Returns 0 when list is empty.

virtual TObjLink *	LastLink () const

virtual TIterator *	MakeIterator (Bool_t dir=kIterForward) const
	Return a list iterator.

virtual void	RecursiveRemove (TObject *obj)
	Remove object from this collection and recursively remove the object from all other objects (and collections).

TObject *	Remove (const TObjLinkPtr_t &lnk)

virtual TObject *	Remove (TObject *obj)
	Remove object from the list.

virtual TObject *	Remove (TObjLink *lnk)
	Remove object link (and therefore the object it contains) from the list.

virtual void	RemoveLast ()
	Remove the last object of the list.

virtual void	Sort (Bool_t order=kSortAscending)
	Sort linked list.

Public Member Functions inherited from TSeqCollection
virtual	~TSeqCollection ()

virtual Int_t	GetLast () const
	Returns index of last object in collection.

virtual Int_t	IndexOf (const TObject *obj) const
	Return index of object in collection.

virtual Bool_t	IsSorted () const

Int_t	LastIndex () const

Long64_t	Merge (TCollection *list)
	Merge this collection with all collections coming in the input list.

virtual void	RemoveAfter (TObject *after)

virtual TObject *	RemoveAt (Int_t idx)

virtual void	RemoveBefore (TObject *before)

virtual void	RemoveFirst ()

void	UnSort ()

Public Member Functions inherited from TCollection
virtual	~TCollection ()
	TNamed destructor.

virtual void	AddAll (const TCollection *col)
	Add all objects from collection col to this collection.

void	AddVector (TObject *obj1,...)
	Add all arguments to the collection.

Bool_t	AssertClass (TClass *cl) const
	Make sure all objects in this collection inherit from class cl.

TIter	begin () const

void	Browse (TBrowser *b)
	Browse this collection (called by TBrowser).

Int_t	Capacity () const

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an collection using the Streamer facility.

Int_t	Compare (const TObject *obj) const
	Compare two TCollection objects.

Bool_t	Contains (const char *name) const

Bool_t	Contains (const TObject *obj) const

virtual void	Draw (Option_t *option="")
	Draw all objects in this collection.

virtual void	Dump () const
	Dump all objects in this collection.

TIter	end () const

virtual Int_t	GetEntries () const

virtual Int_t	GetSize () const
	Return the capacity of the collection, i.e.

virtual Int_t	GrowBy (Int_t delta) const
	Increase the collection's capacity by delta slots.

ULong_t	Hash () const
	Return hash value for this object.

Bool_t	IsArgNull (const char where, const TObject obj) const
	Returns true if object is a null pointer.

virtual Bool_t	IsEmpty () const

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).

Bool_t	IsOwner () const

Bool_t	IsSortable () const

R__ALWAYS_INLINE Bool_t	IsUsingRWLock () const

virtual TIterator *	MakeReverseIterator () const

virtual Bool_t	Notify ()
	'Notify' all objects in this collection.

TObject *	operator() (const char *name) const
	Find an object in this collection by name.

virtual void	Paint (Option_t *option="")
	Paint all objects in this collection.

virtual void	Print (Option_t option, const char wildcard, Int_t recurse=1) const
	Print the collection header and its elements that match the wildcard.

virtual void	Print (Option_t *option, Int_t recurse) const
	Print the collection header and its elements.

virtual void	Print (Option_t *option, TPRegexp &regexp, Int_t recurse=1) const
	Print the collection header and its elements that match the regexp.

virtual void	Print (Option_t *option="") const
	Default print for collections, calls Print(option, 1).

void	RemoveAll ()

virtual void	RemoveAll (TCollection *col)
	Remove all objects in collection col from this collection.

void	SetCurrentCollection ()
	Set this collection to be the globally accessible collection.

void	SetName (const char *name)

virtual void	SetOwner (Bool_t enable=kTRUE)
	Set whether this collection is the owner (enable==true) of its content.

virtual bool	UseRWLock (Bool_t enable=true)
	Set this collection to use a RW lock upon access, making it thread safe.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write all objects in this collection.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write all objects in this collection.

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor.

	TObject (const TObject &object)
	TObject copy ctor.

virtual	~TObject ()
	TObject destructor.

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract.

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad.

ULong_t	CheckedHash ()
	Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.

virtual const char *	ClassName () const
	Returns name of class to which the object belongs.

virtual void	Copy (TObject &object) const
	Copy this to obj.

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object.

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs.

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current selected pad for instance with: `gROOT->SetSelectedPad(gPad)`.

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message.

virtual void	Execute (const char method, const char params, Int_t *error=0)
	Execute method on this object with the given parameter string, e.g.

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray.

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py).

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message.

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object.

virtual const char *	GetIconName () const
	Returns mime type name of object.

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py).

virtual Option_t *	GetOption () const

virtual UInt_t	GetUniqueID () const
	Return the unique object id.

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out.

Bool_t	HasInconsistentHash () const
	Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message.

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname".

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl.

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas.

void	InvertBit (UInt_t f)

Bool_t	IsDestructed () const
	IsDestructed.

R__ALWAYS_INLINE Bool_t	IsOnHeap () const

R__ALWAYS_INLINE Bool_t	IsZombie () const

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary).

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete.

void	operator delete (void *ptr)
	Operator delete.

void	operator delete[] (void *ptr)
	Operator delete [].

void *	operator new (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, void *vp)

TObject &	operator= (const TObject &rhs)
	TObject assignment operator.

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list.

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory.

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename.

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out".

void	SetBit (UInt_t f)

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f.

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object.

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id.

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message.

R__ALWAYS_INLINE Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked.

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message.

Public Member Functions inherited from TQObject
	TQObject ()
	TQObject Constructor.

virtual	~TQObject ()
	TQObject Destructor.

Bool_t	AreSignalsBlocked () const

Bool_t	BlockSignals (Bool_t b)

virtual void	ChangedBy (const char *method)

void	CollectClassSignalLists (TList &list, TClass *cls)
	Collect class signal lists from class cls and all its base-classes.

Bool_t	Connect (const char signal, const char receiver_class, void receiver, const char slot)
	Non-static method is used to connect from the signal of this object to the receiver slot.

virtual void	Connected (const char *)

virtual void	Destroyed ()

Bool_t	Disconnect (const char signal=0, void receiver=0, const char *slot=0)
	Disconnects signal of this object from slot of receiver.

virtual void	Disconnected (const char *)

void	Emit (const char *signal)
	Activate signal without args.

template<typename T >
void	Emit (const char *signal, const T &arg)
	Activate signal with single parameter.

template<typename... T>
void	EmitVA (const char *signal_name, Int_t, const T &... params)
	Emit a signal with a varying number of arguments.

TList *	GetListOfClassSignals () const
	Returns pointer to list of signals of this class.

TList *	GetListOfConnections () const

TList *	GetListOfSignals () const

virtual Bool_t	HasConnection (const char *signal_name) const
	Return true if there is any object connected to this signal.

virtual void	HighPriority (const char signal_name, const char slot_name=0)

virtual void	LowPriority (const char signal_name, const char slot_name=0)

virtual void	Message (const char *msg)

virtual Int_t	NumberOfConnections () const
	Return number of connections for this object.

virtual Int_t	NumberOfSignals () const
	Return number of signals for this object.

Static Public Member Functions
static TQCommand *	GetCommand ()
	Return a command which is doing redo/undo action.

Static Public Member Functions inherited from TSeqCollection
static Int_t	ObjCompare (TObject a, TObject b)
	Compare to objects in the collection. Use member Compare() of object a.

static void	QSort (TObject **a, Int_t first, Int_t last)
	Sort array of TObject pointers using a quicksort algorithm.

static void	QSort (TObject a, Int_t nBs, TObject *b, Int_t first, Int_t last)
	Sort array a of TObject pointers using a quicksort algorithm.

static void	QSort (TObject a, TObject b, Int_t first, Int_t last)

Static Public Member Functions inherited from TCollection
static void	EmptyGarbageCollection ()
	Do the garbage collection.

static void	GarbageCollect (TObject *obj)
	Add to the list of things to be cleaned up.

static TCollection *	GetCurrentCollection ()
	Return the globally accessible collection.

static void	StartGarbageCollection ()
	Set up for garbage collection.

Static Public Member Functions inherited from TObject
static Longptr_t	GetDtorOnly ()
	Return destructor only flag.

static Bool_t	GetObjectStat ()
	Get status of object stat flag.

static void	SetDtorOnly (void *obj)
	Set destructor only flag.

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable.

Static Public Member Functions inherited from TQObject
static Bool_t	AreAllSignalsBlocked ()
	Returns true if all signals are blocked.

static Bool_t	BlockAllSignals (Bool_t b)
	Block or unblock all signals. Returns the previous block status.

static Bool_t	Connect (const char sender_class, const char signal, const char receiver_class, void receiver, const char *slot)
	This method allows to make a connection from any object of the same class to a single slot.

static Bool_t	Connect (TQObject sender, const char signal, const char receiver_class, void receiver, const char *slot)
	Create connection between sender and receiver.

static Bool_t	Disconnect (const char class_name, const char signal, void receiver=0, const char slot=0)
	Disconnects "class signal".

static Bool_t	Disconnect (TQObject sender, const char signal=0, void receiver=0, const char slot=0)
	Disconnects signal in object sender from slot_method in object receiver.

Protected Member Functions
virtual void	Init (const char cl, void object, const char redo, const char undo)
	Common protected method used in several constructors.

virtual void	PrintCollectionHeader (Option_t *option) const
	Print collection header.

Protected Member Functions inherited from TList
TObjLinkPtr_t *	DoSort (TObjLinkPtr_t *head, Int_t n)
	Sort linked list.

TObjLink *	FindLink (const TObject *obj, Int_t &idx) const
	Returns the TObjLink object that contains object obj.

void	InsertAfter (const TObjLinkPtr_t &newlink, const TObjLinkPtr_t &prev)
	Insert a new link in the chain.

TObjLink *	LinkAt (Int_t idx) const
	sorting order (when calling Sort() or for TSortedList)

Bool_t	LnkCompare (const TObjLinkPtr_t &l1, const TObjLinkPtr_t &l2)
	Compares the objects stored in the TObjLink objects.

TObjLinkPtr_t	NewLink (TObject *obj, const TObjLinkPtr_t &prev=nullptr)
	Return a new TObjLink.

TObjLinkPtr_t	NewLink (TObject obj, TObjLink prev)

TObjLinkPtr_t	NewOptLink (TObject obj, Option_t opt, const TObjLinkPtr_t &prev=nullptr)
	Return a new TObjOptLink (a TObjLink that also stores the option).

TObjLinkPtr_t	NewOptLink (TObject obj, Option_t opt, TObjLink *prev)

Protected Member Functions inherited from TSeqCollection
	TSeqCollection ()

virtual void	Changed ()

Protected Member Functions inherited from TCollection
	TCollection ()

virtual const char *	GetCollectionEntryName (TObject *entry) const
	For given collection entry return the string that is used to identify the object and, potentially, perform wildcard/regexp filtering on.

virtual void	PrintCollectionEntry (TObject entry, Option_t option, Int_t recurse) const
	Print the collection entry.

Protected Member Functions inherited from TObject
virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected).

void	MakeZombie ()

Protected Member Functions inherited from TQObject
virtual void *	GetSender ()

virtual const char *	GetSenderClassName () const

Protected Attributes
TString	fName

Bool_t	fNewDelete

Int_t	fNRargs

Int_t	fNUargs

void *	fObject

TQConnection *	fRedo

Long_t *	fRedoArgs

Int_t	fState

Int_t	fStatus

TString	fTitle

TQConnection *	fUndo

Long_t *	fUndoArgs

Protected Attributes inherited from TList
Bool_t	fAscending
	cache to speedup sequential calling of Before() and After() functions

TObjLinkWeakPtr_t	fCache
	pointer to last entry in linked list

TObjLinkPtr_t	fFirst

TObjLinkPtr_t	fLast
	pointer to first entry in linked list

Protected Attributes inherited from TSeqCollection
Bool_t	fSorted

Protected Attributes inherited from TCollection
TString	fName

Int_t	fSize

Protected Attributes inherited from TQObject
TList *	fListOfConnections
	list of signals from this object

TList *	fListOfSignals

Bool_t	fSignalsBlocked
	list of connections to this object

Private Member Functions
TQCommand &	operator= (const TQCommand &)

Friends
class	TQUndoManager

Additional Inherited Members
Public Types inherited from TList
typedef TListIter	Iterator_t

Public Types inherited from TCollection
enum	{ kInitCapacity = 16 , kInitHashTableCapacity = 17 }

Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 , kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) }

enum	EDeprecatedStatusBits { kObjInCanvas = BIT(3) }

enum	EStatusBits { kCanDelete = BIT(0) , kMustCleanup = BIT(3) , kIsReferenced = BIT(4) , kHasUUID = BIT(5) , kCannotPick = BIT(6) , kNoContextMenu = BIT(8) , kInvalidObject = BIT(13) }

Protected Types inherited from TList
using	TObjLinkPtr_t = std::shared_ptr< TObjLink >

using	TObjLinkWeakPtr_t = std::weak_ptr< TObjLink >

Protected Types inherited from TCollection
enum	EStatusBits { kIsOwner = BIT(14) , kUseRWLock = BIT(16) }

Protected Types inherited from TObject
enum	{ kOnlyPrepStep = BIT(3) }

Static Protected Member Functions inherited from TQObject
static Int_t	CheckConnectArgs (TQObject sender, TClass sender_class, const char signal, TClass receiver_class, const char *slot)
	Checking of consistency of sender/receiver methods/arguments.

static TString	CompressName (const char *method_name)
	Removes "const" words and blanks from full (with prototype) method name and resolve any typedefs in the method signature.

static Bool_t	ConnectToClass (const char sender_class, const char signal, TClass receiver_class, void receiver, const char *slot)
	This method allows to make connection from any object of the same class to the receiver object.

static Bool_t	ConnectToClass (TQObject sender, const char signal, TClass receiver_class, void receiver, const char *slot)
	Create connection between sender and receiver.

Static Protected Attributes inherited from TQObject
static Bool_t	fgAllSignalsBlocked = kFALSE
	flag used for suppression of signals

#include <TQCommand.h>

Inheritance diagram for TQCommand:

[legend]

Constructor & Destructor Documentation

◆ TQCommand() [1/3]

TQCommand::TQCommand	(	const char *	clname = `0`,
		void *	obj = `0`,
		const char *	redo = `0`,
		const char *	undo = `0`
	)

Constructor.

Input parameters:

clname - class name.
obj - an object
redo - method or function to do/redo operation
undo - method or function to undo operation

Comments:

if either clname or obj is NULL that means that redo/undo is function
to specify default arguments for redo/undo method/function '=' must precede to argument value.

Example:

TQCommand("TPad", gPad, "SetEditable(=kTRUE)", "SetEditable(=kFALSE)");

undo method can be same as redo one. In that case undo parameter can be omitted.

Example:

TQCommand("TPad", gPad, "SetFillStyle(Style_t)");

Definition at line 168 of file TQCommand.cxx.

◆ TQCommand() [2/3]

TQCommand::TQCommand	(	TObject *	obj,
		const char *	redo = `0`,
		const char *	undo = `0`
	)

Constructor.

Input parameters:

obj - an object
redo - method or function to do/redo operation
undo - method or function to undo operation

Comments: to specify default arguments for redo/undo method/function '=' must precede to argument value.

Example:

TQCommand(gPad, "SetEditable(=kTRUE)", "SetEditable(=kFALSE)");

undo method can be same as redo one. In that case "undo" can parameter be omitted.

Example:

TQCommand(gPad, "SetFillStyle(Style_t)");

Definition at line 199 of file TQCommand.cxx.

◆ TQCommand() [3/3]

TQCommand::TQCommand ( const TQCommand & com )

Copy constructor.

Definition at line 209 of file TQCommand.cxx.

◆ ~TQCommand()

TQCommand::~TQCommand ( )

virtual

dtor.

Definition at line 249 of file TQCommand.cxx.

Member Function Documentation

◆ Add() [1/2]

virtual void TQCommand::Add ( TObject * obj )

inlinevirtual

Reimplemented from TList.

Reimplemented in TQUndoManager.

Definition at line 91 of file TQCommand.h.

◆ Add() [2/2]

void TQCommand::Add	(	TObject *	obj,
		Option_t *	opt
	)

virtual

Add command to the list of merged commands.

Option string can contain substrings:

"compress" - try to compress input command
"radd" - execute redo action of input command
"uadd" - execute undo action of input command

Reimplemented from TList.

Reimplemented in TQUndoManager.

Definition at line 360 of file TQCommand.cxx.

◆ CanCompress()

Bool_t TQCommand::CanCompress ( TQCommand * c ) const

virtual

By default, commands can be compressed if they are:

equal
setter commands

More complicated commands might want to override this function.

Definition at line 387 of file TQCommand.cxx.

◆ CanMerge()

Bool_t TQCommand::CanMerge ( TQCommand * c ) const

virtual

Two commands can be merged if they can be composed into a single command (Macro command).

To allow merging commands user might override this function.

Definition at line 314 of file TQCommand.cxx.

◆ CanRedo()

Bool_t TQCommand::CanRedo ( ) const

virtual

Returns kTRUE if Redo action is possible, kFALSE if it's not.

By default, only single sequential redo action is possible.

Reimplemented in TQUndoManager.

Definition at line 571 of file TQCommand.cxx.

◆ CanUndo()

Bool_t TQCommand::CanUndo ( ) const

virtual

Returns kTRUE if Undo action is possible, kFALSE if it's not.

By default, only single trial undo action is possible.

Reimplemented in TQUndoManager.

Definition at line 580 of file TQCommand.cxx.

◆ Compress()

void TQCommand::Compress ( TQCommand * c )

virtual

Compress command.

Compression is analogous to arithmetic "addition operation".

Note:

The compressed command will be deleted.
Execution Compress method invokes Redo action with new redo arguments inherited from compressed command.

More complicated commands might want to override this function.

Definition at line 402 of file TQCommand.cxx.

◆ Delete()

void TQCommand::Delete ( Option_t * opt = "" )

virtual

If "opt" is not zero delete every merged command which option string is equal to "opt".

If "opt" is zero - delete all merged commands.

Reimplemented from TList.

Definition at line 285 of file TQCommand.cxx.

◆ GetCommand()

TQCommand * TQCommand::GetCommand ( )

static

Return a command which is doing redo/undo action.

This static method allows to set undo parameters dynamically, i.e. during execution of Redo function.

Example: For redo actions like TGTextEdit::DelChar() it is not possible to know ahead what character will be deleted. To set arguments for undo action ( e.g. TGTextEdit::InsChar(char)), one needs to call TQCommand::SetUndoArgs(1, character) from inside of TGTextEdit::DelChar() method, i.e.

TQCommand::GetCommand()->SetUndoArgs(1, somechar);

TQCommand::GetCommand

static TQCommand * GetCommand()

Return a command which is doing redo/undo action.

Definition TQCommand.cxx:276

Definition at line 276 of file TQCommand.cxx.

◆ GetName()

const char * TQCommand::GetName ( ) const

virtual

Returns the command name.

Default name is "ClassName::RedoName(args)" If list of merged commands is not empty the name is "ClassName::RedoName(args):cname1:cname2 ..."

Reimplemented from TCollection.

Definition at line 670 of file TQCommand.cxx.

◆ GetNRargs()

Int_t TQCommand::GetNRargs ( ) const

Returns a number of redo arguments.

Definition at line 768 of file TQCommand.cxx.

◆ GetNUargs()

Int_t TQCommand::GetNUargs ( ) const

Returns a number of undo arguments.

Definition at line 776 of file TQCommand.cxx.

◆ GetObject()

void * TQCommand::GetObject ( ) const

Returns an object for which undo redo actions are applied.

Definition at line 784 of file TQCommand.cxx.

◆ GetRedo()

TQConnection * TQCommand::GetRedo ( ) const

inline

Definition at line 75 of file TQCommand.h.

◆ GetRedoArgs()

Long_t * TQCommand::GetRedoArgs ( ) const

Returns a pointer to array of redo arguments.

Definition at line 752 of file TQCommand.cxx.

◆ GetRedoName()

const char * TQCommand::GetRedoName ( ) const

Returns the name of redo command.

Definition at line 736 of file TQCommand.cxx.

◆ GetStatus()

Int_t TQCommand::GetStatus ( ) const

Returns a number of sequential undo or redo operations.

Definition at line 792 of file TQCommand.cxx.

◆ GetTitle()

const char * TQCommand::GetTitle ( ) const

virtual

Returns command description.

By default, "ClassName::RedoName(args)_ClassName::UndoName(args)"

Reimplemented from TObject.

Definition at line 713 of file TQCommand.cxx.

◆ GetUndo()

TQConnection * TQCommand::GetUndo ( ) const

inline

Definition at line 76 of file TQCommand.h.

◆ GetUndoArgs()

Long_t * TQCommand::GetUndoArgs ( ) const

Returns a pointer to array of undo arguments.

Definition at line 760 of file TQCommand.cxx.

◆ GetUndoName()

const char * TQCommand::GetUndoName ( ) const

Returns the name of undo command.

Definition at line 744 of file TQCommand.cxx.

◆ Init()

void TQCommand::Init	(	const char *	cl,
		void *	object,
		const char *	redo,
		const char *	undo
	)

protectedvirtual

Common protected method used in several constructors.

Definition at line 120 of file TQCommand.cxx.

◆ IsEqual()

Bool_t TQCommand::IsEqual ( const TObject * obj ) const

virtual

Equal comparison.

The commands are equal if they are applied to the same object and have the same Redo/Undo actions

More complicated commands might want to override this function.

Reimplemented from TObject.

Definition at line 418 of file TQCommand.cxx.

◆ IsExecuting()

Bool_t TQCommand::IsExecuting ( ) const

Returns kTRUE if command execution is in progress.

Definition at line 824 of file TQCommand.cxx.

◆ IsMacro()

Bool_t TQCommand::IsMacro ( ) const

Returns kTRUE if neither redo nor undo action specified.

Definition at line 800 of file TQCommand.cxx.

◆ IsRedoing()

Bool_t TQCommand::IsRedoing ( ) const

Redo action is in progress.

Definition at line 816 of file TQCommand.cxx.

◆ IsSetter()

Bool_t TQCommand::IsSetter ( ) const

virtual

Returns kTRUE is command if Redo is the same as Undo function and is the setter action.

By default, all functions with names like "SetXXX" or "setXXX" considered as setters. Another type of setters are Move, Resize operations

More complicated commands might want to override this function.

Definition at line 440 of file TQCommand.cxx.

◆ IsUndoing()

Bool_t TQCommand::IsUndoing ( ) const

Undo action is in progress.

Definition at line 808 of file TQCommand.cxx.

◆ ls()

void TQCommand::ls ( Option_t * option = "" ) const

virtual

ls this command and merged commands

Reimplemented from TCollection.

Reimplemented in TQUndoManager.

Definition at line 848 of file TQCommand.cxx.

◆ Merge() [1/2]

Long64_t TQCommand::Merge	(	TCollection *	collection,
		TFileMergeInfo *
	)

virtual

Merge a collection of TQCommand.

Definition at line 337 of file TQCommand.cxx.

◆ Merge() [2/2]

void TQCommand::Merge ( TQCommand * c )

virtual

Add command to the list of merged commands.

This make it possible to group complex actions together so an end user can undo and redo them with one command. Execution of TQUndoManager::Undo(), TQUndoManager::Redo() methods only invokes the top level command as a whole.

Merge method is analogous to logical join operation.

Note: Merge method invokes redo action.

Definition at line 329 of file TQCommand.cxx.

◆ operator=()

TQCommand & TQCommand::operator= ( const TQCommand & )

private

◆ PrintCollectionHeader()

void TQCommand::PrintCollectionHeader ( Option_t * option ) const

protectedvirtual

Print collection header.

Reimplemented from TCollection.

Definition at line 864 of file TQCommand.cxx.

◆ Redo()

void TQCommand::Redo ( Option_t * option = "" )

virtual

Execute command and then merge commands.

Reimplemented in TQUndoManager.

Definition at line 588 of file TQCommand.cxx.

◆ SetArgs()

void TQCommand::SetArgs	(	Int_t	narg,
			...
	)

virtual

Set do/redo and undo parameters.

The format is SetArgs(number_of_params, redo_params, undo_params)

Example:

move_command->SetArgs(2, 100, 100, 200, 200);

2 params, (100,100) - do/redo position, (200,200) - undo position

Definition at line 465 of file TQCommand.cxx.

◆ SetName()

void TQCommand::SetName ( const char * name )

virtual

Sets name of the command.

Definition at line 832 of file TQCommand.cxx.

◆ SetRedoArgs()

void TQCommand::SetRedoArgs	(	Int_t	narg,
			...
	)

virtual

Set redo parameters.

The format is SetRedoArgs(number_of_params, params)

Example:

move_command->SetRedoArgs(2, 100, 100);

Definition at line 508 of file TQCommand.cxx.

◆ SetTitle()

void TQCommand::SetTitle ( const char * title )

virtual

Sets description of the command.

Definition at line 840 of file TQCommand.cxx.

◆ SetUndoArgs()

void TQCommand::SetUndoArgs	(	Int_t	narg,
			...
	)

virtual

Set undo parameters.

The format is SetUndoArgs(number_of_params, params)

Example:

move_command->SetUndoArgs(2, 200, 200);

Definition at line 542 of file TQCommand.cxx.

◆ Undo()

void TQCommand::Undo ( Option_t * option = "" )

virtual

Un-execute all merged commands and the command.

Merged commands are executed in reverse order.

Reimplemented in TQUndoManager.

Definition at line 626 of file TQCommand.cxx.

Friends And Related Symbol Documentation

◆ TQUndoManager

friend class TQUndoManager

friend

Definition at line 29 of file TQCommand.h.

Member Data Documentation

◆ fName

TString TQCommand::fName

protected

Definition at line 41 of file TQCommand.h.

◆ fNewDelete

Bool_t TQCommand::fNewDelete

protected

Definition at line 40 of file TQCommand.h.

◆ fNRargs

Int_t TQCommand::fNRargs

protected

Definition at line 36 of file TQCommand.h.

◆ fNUargs

Int_t TQCommand::fNUargs

protected

Definition at line 37 of file TQCommand.h.

◆ fObject

void* TQCommand::fObject

protected

Definition at line 43 of file TQCommand.h.

◆ fRedo

TQConnection* TQCommand::fRedo

protected

Definition at line 32 of file TQCommand.h.

◆ fRedoArgs

Long_t* TQCommand::fRedoArgs

protected

Definition at line 34 of file TQCommand.h.

◆ fState

Int_t TQCommand::fState

protected

Definition at line 38 of file TQCommand.h.

◆ fStatus

Int_t TQCommand::fStatus

protected

Definition at line 39 of file TQCommand.h.

◆ fTitle

TString TQCommand::fTitle

protected

Definition at line 42 of file TQCommand.h.

◆ fUndo

TQConnection* TQCommand::fUndo

protected

Definition at line 33 of file TQCommand.h.

◆ fUndoArgs

Long_t* TQCommand::fUndoArgs

protected

Definition at line 35 of file TQCommand.h.

core/base/inc/TQCommand.h

core/base/src/TQCommand.cxx

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Friends

Additional Inherited Members

Constructor & Destructor Documentation

◆ TQCommand() [1/3]

◆ TQCommand() [2/3]

◆ TQCommand() [3/3]

◆ ~TQCommand()

Member Function Documentation

◆ Add() [1/2]

◆ Add() [2/2]

◆ CanCompress()

◆ CanMerge()

◆ CanRedo()

◆ CanUndo()

◆ Compress()

◆ Delete()

◆ GetCommand()

◆ GetName()

◆ GetNRargs()

◆ GetNUargs()

◆ GetObject()

◆ GetRedo()

◆ GetRedoArgs()

◆ GetRedoName()

◆ GetStatus()

◆ GetTitle()

◆ GetUndo()

◆ GetUndoArgs()

◆ GetUndoName()

◆ Init()

◆ IsEqual()

◆ IsExecuting()

◆ IsMacro()

◆ IsRedoing()

◆ IsSetter()

◆ IsUndoing()

◆ ls()

◆ Merge() [1/2]

◆ Merge() [2/2]

◆ operator=()

◆ PrintCollectionHeader()

◆ Redo()

◆ SetArgs()

◆ SetName()

◆ SetRedoArgs()

◆ SetTitle()

◆ SetUndoArgs()

◆ Undo()

Friends And Related Symbol Documentation

◆ TQUndoManager

Member Data Documentation

◆ fName

◆ fNewDelete

◆ fNRargs

◆ fNUargs

◆ fObject

◆ fRedo

◆ fRedoArgs

◆ fState

◆ fStatus

◆ fTitle

◆ fUndo

◆ fUndoArgs