Class: Concurrent::Event

Inherits:
Object
  • Object
show all
Defined in:
lib/concurrent/event.rb

Overview

Old school kernel-style event reminiscent of Win32 programming in C++.

When an Event is created it is in the unset state. Threads can choose to #wait on the event, blocking until released by another thread. When one thread wants to alert all blocking threads it calls the #set method which will then wake up all listeners. Once an Event has been set it remains set. New threads calling #wait will return immediately. An Event may be #reset at any time once it has been set.

See Also:

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Event

Creates a new Event in the unset state. Threads calling #wait on the Event will block.



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# File 'lib/concurrent/event.rb', line 21

def initialize
  @set = false
  @mutex = Mutex.new
  @condition = Condition.new
end

Instance Method Details

#reset ⇒ Boolean

Reset a previously set event back to the unset state. Has no effect if the Event has not yet been set.

Returns:

  • (Boolean) —

    should always return true



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# File 'lib/concurrent/event.rb', line 54

def reset
  @mutex.synchronize do
    @set = false
  end

  true
end

#set ⇒ Boolean

Trigger the event, setting the state to set and releasing all threads waiting on the event. Has no effect if the Event has already been set.

Returns:

  • (Boolean) —

    should always return true



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# File 'lib/concurrent/event.rb', line 40

def set
  @mutex.synchronize do
    return true if @set
    @set = true
    @condition.broadcast
  end

  true
end

#set? ⇒ Boolean

Is the object in the set state?

Returns:

  • (Boolean) —

    indicating whether or not the Event has been set



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# File 'lib/concurrent/event.rb', line 30

def set?
  @mutex.synchronize do
    @set
  end
end

#wait(timeout = nil) ⇒ Boolean

Wait a given number of seconds for the Event to be set by another thread. Will wait forever when no timeout value is given. Returns immediately if the Event has already been set.

Returns:

  • (Boolean) —

    true if the Event was set before timeout else false



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# File 'lib/concurrent/event.rb', line 67

def wait(timeout = nil)
  @mutex.synchronize do
    return true if @set

    remaining = Condition::Result.new(timeout)
    while !@set && remaining.can_wait?
      remaining = @condition.wait(@mutex, remaining.remaining_time)
    end

    @set
  end
end