Class: Lock

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
app/models/lock.rb

Class Method Summary collapse

Class Method Details

.get(name, args = {}) ⇒ Object

Get an atomic lock if value matches or is nil. Block until lock was successful if args was set to true



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# File 'app/models/lock.rb', line 4

def self.get name, args = {}
  poll_time = args[:poll_time] || 10
  until (lock = get_lock_for(name, args)) || args[:blocking] != true do
    sleep poll_time
  end
  lock
end

.get_value(name) ⇒ Object

Return value of a lock. When no lock was found, nil will be returned.



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# File 'app/models/lock.rb', line 48

def self.get_value name
  lock = self.where(:name => name).first
  if lock
    lock.value.nil? ? '' : lock.value
  else
    nil
  end
end

.release(names, args = {}) ⇒ Object

Release an atomic lock if value matches or is nil



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# File 'app/models/lock.rb', line 14

def self.release names, args = {}
  successful = false

  if name
    # If names is a single string, transorm it to an array
    names = [names.to_s] if names.class == String || names.class == Symbol

    self.transaction do
      locks = self.where(:name => names).lock(true).all

      unless locks.blank?
        successful = true
        # Check, if the value of every selected lock matches the args[:value] unless no args[:value] was specified
        locks.each{ |l| successful = false unless (args[:value].nil? || (args[:value] != nil && args[:value] == l.value)) }
        # Now destroy the locks, if it is successful
        locks.each{ |l| l.destroy } if successful
      end
    end
  end

  successful
end

.release_all ⇒ Object

Destroy all locks in one atomic operation



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# File 'app/models/lock.rb', line 59

def self.release_all
  self.transaction do
    self.all.each { |l| l.destroy }
  end
end

.release_for_task(task) ⇒ Object

Release all locks for a given task. This is only working, if the value was set to “task #tasktask.id”



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# File 'app/models/lock.rb', line 39

def self.release_for_task task
  self.transaction do
    locks = self.where(:value => "task #{task.id}").lock(true).all
    locks.each{ |l| l.destroy }
  end
end