ConditionVariable (Class)

In: thread.rb
Parent: Object

ConditionVariable objects augment class Mutex. Using condition variables, it is possible to suspend while in the middle of a critical section until a resource becomes available (see the discussion on page 117).

Example: 

  require 'thread'

  mutex = Mutex.new
  resource = ConditionVariable.new

  a = Thread.new {
    mutex.synchronize {
      # Thread 'a' now needs the resource
      resource.wait(mutex)
      # 'a' can now have the resource
    }
  }

  b = Thread.new {
    mutex.synchronize {
      # Thread 'b' has finished using the resource
      resource.signal
    }
  }

Methods

broadcast   new   signal   wait  

Public Class methods

new()

[Source]

# File thread.rb, line 184
  def initialize
    @waiters = []
  end

Public Instance methods

broadcast()

Wakes up all threads waiting for this lock.

[Source]

# File thread.rb, line 214
  def broadcast
    waiters0 = nil
    Thread.exclusive do
      waiters0 = @waiters.dup
      @waiters.clear
    end
    for t in waiters0
      begin
        t.run
      rescue ThreadError
      end
    end
  end
signal()

Wakes up the first thread in line waiting for this lock.

[Source]

# File thread.rb, line 202
  def signal
    begin
      t = @waiters.shift
      t.run if t
    rescue ThreadError
      retry
    end
  end
wait(mutex)

Releases the lock held in mutex and waits; reacquires the lock on wakeup.

[Source]

# File thread.rb, line 191
  def wait(mutex)
    mutex.exclusive_unlock do
      @waiters.push(Thread.current)
      Thread.stop
    end
    mutex.lock
  end

[Validate]