<!-- TTask.md --- 
;; 
;; Description: 
;; Author: Hongyi Wu(吴鸿毅)
;; Email: wuhongyi@qq.com 
;; Created: 六 8月 13 20:40:51 2016 (+0800)
;; Last-Updated: 三 9月 16 10:27:39 2020 (+0800)
;;           By: Hongyi Wu(吴鸿毅)
;;     Update #: 2
;; URL: http://wuhongyi.cn -->

# TTask+

## class

继承TNamed

Base class for recursive execution of tasks.

TTask is a base class that can be used to build a complex tree of Tasks.
Each TTask derived class may contain other TTasks that can be executed
recursively, such that a complex program can be dynamically built and executed
by invoking the services of the top level Task or one of its subtasks.

Use the TTask::Add function to add a subtask to an existing TTask.
To execute a TTask, one calls the ExecuteTask function. ExecuteTask will
call recursively:

  - the TTask::Exec function of the derived class
  - TTask::ExecuteTasks to execute for each task the list of its subtasks.

If the top level task (see example below) is added to the list of Root
browsable objects, the tree of tasks can be visualized by the Root browser.
The browser can be used to start a task, set break points at the beginning
of a task or when the task has completed. At a breakpoint, data structures
generated by the execution up this point may be inspected asynchronously
and then the execution can be resumed by selecting the "Continue" function
of a task.

A Task may be active or inactive (controlled by TTask::SetActive).
When a task is not active, its sub tasks are not executed.

A TTask tree may be made persistent, saving the status of all the tasks.

```cpp
   TTask();
   TTask(const char* name, const char *title);
   virtual ~TTask();
   TTask(const TTask &task);
   TTask& operator=(const TTask& tt);

   virtual void  Abort();  // *MENU*
   virtual void  Add(TTask *task) {fTasks->Add(task);}
   virtual void  Browse(TBrowser *b);
   virtual void  CleanTasks();
   virtual void  Clear(Option_t *option="");
   virtual void  Continue(); // *MENU*
   virtual void  Exec(Option_t *option);
   virtual void  ExecuteTask(Option_t *option="0");  // *MENU*
   virtual void  ExecuteTasks(Option_t *option);
   Int_t         GetBreakin() const { return fBreakin; }
   Int_t         GetBreakout() const { return fBreakout; }
         Bool_t  IsActive() const { return fActive; }
         Bool_t  IsFolder() const { return kTRUE; }
   virtual void  ls(Option_t *option="*") const;  // *MENU*
           void  SetActive(Bool_t active=kTRUE) { fActive = active; } // *TOGGLE*
           void  SetBreakin(Int_t breakin=1) { fBreakin = breakin; } // *TOGGLE*
           void  SetBreakout(Int_t breakout=1) { fBreakout = breakout; } // *TOGGLE*
   TList        *GetListOfTasks() const { return fTasks; }
```

## code


```cpp
//The Root browser's picture below has been generated by executing the following script:
{
   TTask *aliroot  = new TTask("aliroot","ALICE reconstruction main task");
   TTask *geominit = new TTask("geomInit","Initialize ALICE geometry");
   TTask *matinit  = new TTask("matInit","Initialize ALICE materials");
   TTask *physinit = new TTask("physInit","Initialize Physics processes");
   TTask *tracker  = new TTask("tracker","Track reconstruction manager");
   TTask *tpcrec   = new TTask("tpcrec","TPC reconstruction");
   TTask *itsrec   = new TTask("itsrec","ITS reconstruction");
   TTask *muonrec  = new TTask("muonRec","Muon Reconstruction");
   TTask *phosrec  = new TTask("phosRec","Phos Reconstruction");
   TTask *richrec  = new TTask("richRec","Rich Reconstruction");
   TTask *trdrec   = new TTask("trdRec","TRD Reconstruction");
   TTask *globrec  = new TTask("globRec","Global Track Reconstruction");
   TTask *pstats   = new TTask("printStats","Print Run Statistics");
   TTask *run      = new TTask("run","Process one run");
   TTask *event    = new TTask("event","Process one event");
   aliroot->Add(geominit);
   aliroot->Add(matinit);
   aliroot->Add(physinit);
   aliroot->Add(run);
   run->Add(event);
   event->Add(tracker);
   event->Add(muonrec);
   event->Add(phosrec);
   event->Add(richrec);
   event->Add(trdrec);
   event->Add(globrec);
   tracker->Add(tpcrec);
   tracker->Add(itsrec);
   run->Add(pstats);

   gROOT->GetListOfBrowsables()->Add(aliroot,"aliroot");
   new TBrowser;
}
```


## example


<!-- TTask.md ends here -->