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Class: Concurrent::AbstractExchanger

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
JavaExchanger, RubyExchanger
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Synchronization::Object, Synchronization::AbstractObject
Instance Chain:
self, Synchronization::Object, Synchronization::Volatile, Synchronization::AbstractObject
Inherits: Concurrent::Synchronization::Object
Defined in: lib/concurrent-ruby/concurrent/exchanger.rb

Constant Summary

Class Attribute Summary

Synchronization::Object - Inherited

.safe_initialization?

Class Method Summary

Synchronization::Object - Inherited

.atomic_attribute?, .atomic_attributes,
.attr_atomic

Creates methods for reading and writing to a instance variable with volatile (Java) semantic as .attr_volatile does.
.attr_volatile

Creates methods for reading and writing (as attr_accessor does) to a instance variable with volatile (Java) semantic.
.ensure_safe_initialization_when_final_fields_are_present

For testing purposes, quite slow.
.new

Has to be called by children.
.safe_initialization!, .define_initialize_atomic_fields

Synchronization::AbstractObject - Inherited

.attr_volatile, .new

Instance Method Summary

Synchronization::Object - Inherited

#__initialize_atomic_fields__

Synchronization::Volatile - Included

#full_memory_barrier

Synchronization::AbstractObject - Inherited

#full_memory_barrier

Constructor Details

.new ⇒ AbstractExchanger

[ GitHub ] 

  


# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 44



def initialize
  super
end


  







Instance Method Details



  

    #do_exchange(value, timeout)  ⇒ Object, CANCEL  (private)
  



  

    

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is nil the method will block indefinitely.


  





  
Parameters:


    
  
  • 
    value
    (Object)
—    
    

    the value to exchange with another thread
    

    
  
    • 
  
  • 
    timeout
    (Numeric, nil)
—    
    

    in seconds, nil blocks indefinitely
    

    
  
    • 



Returns:



Raises:


    
  
  • 
    (NotImplementedError)
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 122



def do_exchange(value, timeout)
  raise NotImplementedError
end


  








  

    #exchange(value, timeout = nil)  ⇒ Object 
  



  

    

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is nil the method will block indefinitely.



In some edge cases when a timeout is given a return value of nil may be ambiguous. Specifically, if nil is a valid value in the exchange it will be impossible to tell whether nil is the actual return value or if it signifies timeout. When nil is a valid value in the exchange consider using #exchange! or #try_exchange instead.


  





  
Parameters:


    
  
  • 
    value
    (Object)
—    
    

    the value to exchange with another thread
    

    
  
    • 
  
  • 
    timeout
    (Numeric, nil)
    (defaults to: nil)
—    
    

    in seconds, nil blocks indefinitely
    

    
  
    • 



Returns:


    
  
  • 
    (Object)
—    
    

    the value exchanged by the other thread or nil on timeout
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 69



def exchange(value, timeout = nil)
  (value = do_exchange(value, timeout)) == CANCEL ? nil : value
end


  








  

    #exchange!(value, timeout = nil)  ⇒ Object 
  



  

    

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is nil the method will block indefinitely.



On timeout a TimeoutError exception will be raised.


  





  
Parameters:


    
  
  • 
    value
    (Object)
—    
    

    the value to exchange with another thread
    

    
  
    • 
  
  • 
    timeout
    (Numeric, nil)
    (defaults to: nil)
—    
    

    in seconds, nil blocks indefinitely
    

    
  
    • 



Returns:


    
  
  • 
    (Object)
—    
    

    the value exchanged by the other thread
    

    
  
    • 



Raises:





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 80



def exchange!(value, timeout = nil)
  if (value = do_exchange(value, timeout)) == CANCEL
    raise Concurrent::TimeoutError
  else
    value
  end
end


  








  

    #try_exchange(value, timeout = nil)  ⇒ Concurrent::Maybe 
  



  

    

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is nil the method will block indefinitely.



The return value will be a Maybe set to Just on success or Nothing on timeout.


  





    

    
Examples:

      
exchanger = Concurrent::Exchanger.new

result = exchanger.exchange(:foo, 0.5)

if result.just?
  puts result.value #=> :bar
else
  puts 'timeout'
end

  


Parameters:


    
  
  • 
    value
    (Object)
—    
    

    the value to exchange with another thread
    

    
  
    • 
  
  • 
    timeout
    (Numeric, nil)
    (defaults to: nil)
—    
    

    in seconds, nil blocks indefinitely
    

    
  
    • 



Returns:


    
  
  • 
    (Concurrent::Maybe)
—    
    

    on success a Just maybe will be returned with the item exchanged by the other thread as ‘#value`; on timeout a Nothing maybe will be returned with TimeoutError as #reason
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 109



def try_exchange(value, timeout = nil)
  if (value = do_exchange(value, timeout)) == CANCEL
    Concurrent::Maybe.nothing(Concurrent::TimeoutError)
  else
    Concurrent::Maybe.just(value)
  end
end