Re: proc based observers

[Sami Wagiaalla <swagiaal at redhat dot com>]

> Do you have some examples of code that does that in frysk at the moment?
>   
There are a couple of instances in the gui. Here is an example from 
Ftrace.java:

ProcObserver.ProcTasks tasksObserver = new ProcObserver.ProcTasks()
 {
   public void existingTask (Task task)
   {
     handleTask(task);
   }

   public void taskAdded (Task task)
   {
     handleTask(task);
   }

   public void taskRemoved (Task arg0)
   {
   }

   public void addedTo (Object arg0)
   {
   }

   public void addFailed (Object arg0, Throwable arg1)
   {
   }

   public void deletedFrom (Object arg0)
   {
   }
 };


Then handle task does this:

synchronized void handleTask (Task task)
 {
   task.requestAddSyscallObserver(syscallObserver);
   task.requestAddForkedObserver(forkedObserver);
   Proc proc = task.getProc();
 ....

The history behind this is interesting:

We used to have some proc observers, but we wanted fine grain control so 
everything was moved down to tasks. then we wanted a safe way of getting 
a procs tasks, so we created ProcTasksObserver. And now the common case 
(at least outside of monitor) is to add observers to all tasks.