Class SizedQueue
In: lib/thread.rb
Parent: Queue

This class represents queues of specified size capacity. The push operation may be blocked if the capacity is full.

See Queue for an example of how a SizedQueue works.

Methods

<<   deq   enq   max   max=   new   num_waiting   pop   push   shift  

Public Class methods

new(max)

Creates a fixed-length queue with a maximum size of max.

[Source]

     # File lib/thread.rb, line 379
379:   def initialize(max)
380:     raise ArgumentError, "queue size must be positive" unless max > 0
381:     @max = max
382:     @queue_wait = []
383:     @queue_wait.taint           # enable tainted comunication
384:     super()
385:   end

Public Instance methods

<<(obj)

Alias for push

deq(*args)

Alias for pop

enq(obj)

Alias for push

max()

Returns the maximum size of the queue.

[Source]

     # File lib/thread.rb, line 390
390:   def max
391:     @max
392:   end
max=(max)

Sets the maximum size of the queue.

[Source]

     # File lib/thread.rb, line 397
397:   def max=(max)
398:     Thread.critical = true
399:     if max <= @max
400:       @max = max
401:       Thread.critical = false
402:     else
403:       diff = max - @max
404:       @max = max
405:       Thread.critical = false
406:       diff.times do
407:         begin
408:           t = @queue_wait.shift
409:           t.run if t
410:         rescue ThreadError
411:           retry
412:         end
413:       end
414:     end
415:     max
416:   end
num_waiting()

Returns the number of threads waiting on the queue.

[Source]

     # File lib/thread.rb, line 478
478:   def num_waiting
479:     @waiting.size + @queue_wait.size
480:   end
pop(*args)

Retrieves data from the queue and runs a waiting thread, if any.

[Source]

     # File lib/thread.rb, line 445
445:   def pop(*args)
446:     retval = super
447:     Thread.critical = true
448:     if @que.length < @max
449:       begin
450:         t = @queue_wait.shift
451:         t.wakeup if t
452:       rescue ThreadError
453:         retry
454:       ensure
455:         Thread.critical = false
456:       end
457:       begin
458:         t.run if t
459:       rescue ThreadError
460:       end
461:     end
462:     retval
463:   end
push(obj)

Pushes obj to the queue. If there is no space left in the queue, waits until space becomes available.

[Source]

     # File lib/thread.rb, line 422
422:   def push(obj)
423:     Thread.critical = true
424:     while @que.length >= @max
425:       @queue_wait.push Thread.current
426:       Thread.stop
427:       Thread.critical = true
428:     end
429:     super
430:   end
shift(*args)

Alias for pop

[Validate]