1Padre::TaskManager(3) User Contributed Perl DocumentationPadre::TaskManager(3)
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NAME

6       Padre::TaskManager - Padre Background Task Scheduler
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SYNOPSIS

9         require Padre::Task::Foo;
10         my $task = Padre::Task::Foo->new(some => 'data');
11         $task->schedule; # handed off to the task manager
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DESCRIPTION

14       Padre uses threads for asynchronous background operations which may
15       take so long that they would make the GUI unresponsive if run in the
16       main (GUI) thread.
17
18       This class implements a pool of a configurable number of re-usable
19       worker threads. Re-using threads is necessary as the overhead of
20       spawning threads is high. Additional threads are spawned if many
21       background tasks are scheduled for execution.  When the load goes down,
22       the number of extra threads is (slowly!)  reduced down to the default.
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INTERFACE

25   Class Methods
26       "new"
27
28       The constructor returns a "Padre::TaskManager" object.  At the moment,
29       "Padre::TaskManager" is a singleton.  An object is instantiated when
30       the editor object is created.
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32       Optional parameters:
33
34       min_no_workers / max_no_workers
35         Set the minimum and maximum number of worker threads to spawn.
36         Default: 1 to 3
37
38         The first workers are spawned lazily: I.e. only when the first task
39         is being scheduled.
40
41       use_threads
42         Disable for profiling runs. In the degraded, thread-less mode, all
43         tasks are run in the main thread. Default: 1 (use threads)
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45       reap_interval
46         The number of milliseconds to wait before checking for dead worker
47         threads. Default: 15000ms
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49   Instance Methods
50       "schedule"
51
52       Given a "Padre::Task" instance (or rather an instance of a subclass),
53       schedule that task for execution in a worker thread.  If you call the
54       "schedule" method of the task object, it will proxy to this method for
55       convenience.
56
57       "setup_workers"
58
59       Create more workers if necessary. Called by "reap" which is called
60       regularly by the reap timer, so users don't typically need to call
61       this.
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63       "reap"
64
65       Check for worker threads that have exited and can be joined.  If there
66       are more worker threads than the normal number and they are idle, one
67       worker thread (per "reap" call) is stopped.
68
69       This method is called regularly by the reap timer (see the
70       "reap_interval" option to the constructor) and it's not typically
71       called by users.
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73       "cleanup"
74
75       Shutdown all services with a HANGUP, then stop all worker threads.
76       Called on editor shutdown.
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78   Accessors
79       "task_queue"
80
81       Returns the queue of tasks to be processed as a Thread::Queue object.
82       The tasks in the queue have been serialized for passing between
83       threads, so this is mostly useful internally or for checking the number
84       of outstanding jobs.
85
86       "reap_interval"
87
88       Returns the number of milliseconds between the regular cleanup runs.
89
90       "use_threads"
91
92       Returns whether running in degraded mode (no threads, false) or normal
93       operation (threads, true).
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95       "running_tasks"
96
97       Returns the number of tasks that are currently being executed.
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99       "shutdown_services"
100
101       Gracefully shutdown the services by instructing them to hangup
102       themselves and return via the usual Task mechanism.
103
104       "workers"
105
106       Returns a list of the worker threads.
107
108   Event Handlers
109       "on_task_done_event"
110
111       This event handler is called when a background task has finished
112       execution. It deserializes the background task object and calls its
113       "finish" method with the Padre main window object as first argument.
114       (This is done because "finish" most likely updates the GUI.)
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116       "on_task_start_event"
117
118       This event handler is called when a background task is about to start
119       execution.  It simply increments the running task counter.
120
121       "on_service_poll_event"
122
123       "on_dump_running_tasks"
124
125       Called by the toolbar task-status button.  Dumps the list of running
126       tasks to the output panel.
127

TO DO

129       What if the computer can't keep up with the queued jobs? This needs
130       some consideration and probably, the "schedule()" call needs to block
131       once the queue is "full". However, it's not clear how this can work if
132       the Wx "MainLoop" isn't reached for processing finish events.
133
134       Polling services aliveness in a useful way, something a
135       "Wx::Taskmanager" might like to display. Ability to selectively kill
136       tasks/services
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SEE ALSO

139       The base class of all "work units" is Padre::Task.
140

AUTHOR

142       Steffen Mueller "smueller@cpan.org"
143

145       Copyright 2008-2010 The Padre development team as listed in Padre.pm.
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147       This program is free software; you can redistribute it and/or modify it
148       under the same terms as Perl 5 itself.
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152perl v5.12.1                      2010-06-11             Padre::TaskManager(3)
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