Class: ThreadsWait

Inherits:
Object
  • Object
show all
Extended by:
Exception2MessageMapper
Defined in:
lib/thwait.rb

Overview

This class watches for termination of multiple threads. Basic functionality (wait until specified threads have terminated) can be accessed through the class method ThreadsWait::all_waits. Finer control can be gained using instance methods.

Example:

ThreadsWait.all_waits(thr1, thr2, ...) do |t|
  STDERR.puts "Thread #{t} has terminated."
end

th = ThreadsWait.new(thread1,...)
th.next_wait # next one to be done

Constant Summary collapse

RCS_ID = 
'-$Id: thwait.rb,v 1.3 1998/06/26 03:19:34 keiju Exp keiju $-'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*threads) ⇒ ThreadsWait

Creates a ThreadsWait object, specifying the threads to wait on. Non-blocking.



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# File 'lib/thwait.rb', line 53

def initialize(*threads)
  @threads = []
  @wait_queue = Queue.new
  join_nowait(*threads) unless threads.empty?
end

Instance Attribute Details

#threads ⇒ Object (readonly)

Returns the array of threads that have not terminated yet.



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# File 'lib/thwait.rb', line 60

def threads
  @threads
end

Class Method Details

.all_waits(*threads) ⇒ Object

Waits until all specified threads have terminated. If a block is provided, it is executed for each thread as they terminate.



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# File 'lib/thwait.rb', line 38

def ThreadsWait.all_waits(*threads) # :yield: thread
  tw = ThreadsWait.new(*threads)
  if block_given?
    tw.all_waits do |th|
      yield th
    end
  else
    tw.all_waits
  end
end

Instance Method Details

#all_waits ⇒ Object

Waits until all of the specified threads are terminated. If a block is supplied for the method, it is executed for each thread termination.

Raises exceptions in the same manner as next_wait.



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# File 'lib/thwait.rb', line 126

def all_waits
  until @threads.empty?
    th = next_wait
    yield th if block_given?
  end
end

#empty? ⇒ Boolean

Returns true if there are no threads in the pool still running.



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# File 'lib/thwait.rb', line 65

def empty?
  @threads.empty?
end

#finished? ⇒ Boolean

Returns true if any thread has terminated and is ready to be collected.



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# File 'lib/thwait.rb', line 72

def finished?
  !@wait_queue.empty?
end

#join(*threads) ⇒ Object

Waits for specified threads to terminate, and returns when one of the threads terminated.



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# File 'lib/thwait.rb', line 80

def join(*threads)
  join_nowait(*threads)
  next_wait
end

#join_nowait(*threads) ⇒ Object

Specifies the threads that this object will wait for, but does not actually wait.



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# File 'lib/thwait.rb', line 89

def join_nowait(*threads)
  threads.flatten!
  @threads.concat threads
  for th in threads
    Thread.start(th) do |t|
      begin
        t.join
      ensure
        @wait_queue.push t
      end
    end
  end
end

#next_wait(nonblock = nil) ⇒ Object

Waits until any of the specified threads has terminated, and returns the one that does.

If there is no thread to wait, raises ErrNoWaitingThread. If nonblock is true, and there is no terminated thread, raises ErrNoFinishedThread.



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# File 'lib/thwait.rb', line 110

def next_wait(nonblock = nil)
  ThreadsWait.fail ErrNoWaitingThread if @threads.empty?
  begin
    @threads.delete(th = @wait_queue.pop(nonblock))
    th
  rescue ThreadError
    ThreadsWait.fail ErrNoFinishedThread
  end
end