TFolder

Class Description

 A TFolder object is a collection of objects and folders.
 Folders have a name and a title and are identified in the folder hierarchy
 by a "Unix-like" naming mechanism. The root of all folders is //root.
 New folders can be dynamically added or removed to/from a folder.
 The folder hierarchy can be visualized via the TBrowser.

 The Root folders hierarchy can be seen as a whiteboard where objects
 are posted. Other classes/tasks can access these objects by specifying
 only a string pathname. This whiteboard facility greatly improves the
 modularity of an application, minimizing the class relationship problem
 that penalizes large applications.

 Pointers are efficient to communicate between classes.
 However, one has interest to minimize direct coupling between classes
 in the form of direct pointers. One better uses the naming and search
 service provided by the Root folders hierarchy. This makes the classes
 loosely coupled and also greatly facilitates I/O operations.
 In a client/server environment, this mechanism facilitates the access
 to any kind of object in //root stores running on different processes.

 A TFolder is created by invoking the TFolder constructor. It is placed
 inside an existing folder via the TFolder::AddFolder method.
 One can search for a folder or an object in a folder using the FindObject
 method. FindObject analyzes the string passed as its argument and searches
 in the hierarchy until it finds an object or folder matching the name.

 When a folder is deleted, its reference from the parent folder and
 possible other folders is deleted.

 If a folder has been declared the owner of its objects/folders via
 TFolder::SetOwner, then the contained objects are deleted when the
 folder is deleted. By default, a folder does not own its contained objects.
 NOTE that folder ownership can be set
   - via TFolder::SetOwner
   - or via TCollection::SetOwner on the collection specified to TFolder::AddFolder

 Standard Root objects are automatically added to the folder hierarchy.
 For example, the following folders exist:
   //root/Files      with the list of currently connected Root files
   //root/Classes    with the list of active classes
   //root/Geometries with active geometries
   //root/Canvases   with the list of active canvases
   //root/Styles     with the list of graphics styles
   //root/Colors     with the list of active colors

 For example, if a file "myFile.root" is added to the list of files, one can
 retrieve a pointer to the corresponding TFile object with a statement like:
   TFile *myFile = (TFile*)gROOT->FindObject("//root/Files/myFile.root");
 The above statement can be abbreviated to:
   TFile *myFile = (TFile*)gROOT->FindObject("/Files/myFile.root");
 or even to:
   TFile *myFile = (TFile*)gROOT->FindObjectAny("myFile.root");
 In this last case, the TROOT::FindObjectAny function will scan the folder hierarchy
 starting at //root and will return the first object named "myFile.root".

 Because a string-based search mechanism is expensive, it is recommended
 to save the pointer to the object as a class member or local variable
 if this pointer is used frequently or inside loops.