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Class: Concurrent::AtomicFixnum

Relationships & Source Files
Inherits: Concurrent::AtomicFixnumImplementation
Defined in: lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb

Overview

A numeric value that can be updated atomically. Reads and writes to an atomic fixnum and thread-safe and guaranteed to succeed. Reads and writes may block briefly but no explicit locking is required.

## Thread-safe Variable Classes

Each of the thread-safe variable classes is designed to solve a different problem. In general:

  • *Agent:* Shared, mutable variable providing independent, uncoordinated, asynchronous change of individual values. Best used when the value will undergo frequent, complex updates. Suitable when the result of an update does not need to be known immediately.

  • *Atom:* Shared, mutable variable providing independent, uncoordinated, synchronous change of individual values. Best used when the value will undergo frequent reads but only occasional, though complex, updates. Suitable when the result of an update must be known immediately.

  • *AtomicReference:* A simple object reference that can be updated atomically. Updates are synchronous but fast. Best used when updates a simple set operations. Not suitable when updates are complex. AtomicBoolean and AtomicFixnum are similar but optimized for the given data type.

  • *Exchanger:* Shared, stateless synchronization point. Used when two or more threads need to exchange data. The threads will pair then block on each other until the exchange is complete.

  • *MVar:* Shared synchronization point. Used when one thread must give a value to another, which must take the value. The threads will block on each other until the exchange is complete.

  • *ThreadLocalVar:* Shared, mutable, isolated variable which holds a different value for each thread which has access. Often used as an instance variable in objects which must maintain different state for different threads.

  • *TVar:* Shared, mutable variables which provide coordinated, synchronous, change of many stated. Used when multiple value must change together, in an all-or-nothing transaction.

Performance:

“‘ Testing with ruby 2.1.2 Testing with MutexAtomicFixnum…

3.130000   0.000000   3.130000 (  3.136505)

Testing with CAtomicFixnum…

0.790000   0.000000   0.790000 (  0.785550)

Testing with jruby 1.9.3 Testing with MutexAtomicFixnum…

5.460000   2.460000   7.920000 (  3.715000)

Testing with Concurrent::JavaAtomicFixnum…

4.520000   0.030000   4.550000 (  1.187000)

“‘

See Also:

Class Method Summary

Instance Method Summary

Constructor Details

.new(initial = 0)

Creates a new AtomicFixnum with the given initial value.

Parameters:

  • initial (Fixnum) (defaults to: 0) —

    the initial value

Raises:

  • (ArgumentError) —

    if the initial value is not a Fixnum

[ GitHub ] 

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end


  







Instance Method Details



  

    #compare_and_set(expect, update)  ⇒ Boolean 
  



  

    

Atomically sets the value to the given updated value if the current value == the expected value.


  





  
Parameters:


    
  
  • 
    expect
    (Fixnum)
—    
    

    the expected value
    

    
  
    • 
  
  • 
    update
    (Fixnum)
—    
    

    the new value
    

    
  
    • 



Returns:


    
  
  • 
    (Boolean)
—    
    

    true if the value was updated else false
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end


  








  

    #decrement(delta = 1)  ⇒ Fixnum 
  



  

    

Decreases the current value by the given amount (defaults to 1).


  





  
Parameters:


    
  
  • 
    delta
    (Fixnum)
    (defaults to: 1)
—    
    

    the amount by which to decrease the current value
    

    
  
    • 



Returns:


    
  
  • 
    (Fixnum)
—    
    

    the current value after decrementation
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end


  








  

    #increment(delta = 1)  ⇒ Fixnum 
  



  

    

Increases the current value by the given amount (defaults to 1).


  





  
Parameters:


    
  
  • 
    delta
    (Fixnum)
    (defaults to: 1)
—    
    

    the amount by which to increase the current value
    

    
  
    • 



Returns:


    
  
  • 
    (Fixnum)
—    
    

    the current value after incrementation
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end


  








  

    #inspect  
  



  

    

Alias for #to_s.


  



  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 142



alias_method :inspect, :to_s


  








  

    #to_s  ⇒ String 
    Also known as: #inspect
  



  

    
  





  
Returns:


    
  
  • 
    (String)
—    
    

    Short string representation.
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 138



def to_s
  format '%s value:%s>', super[0..-2], value
end


  








  

    #update {|Object| ... } ⇒ Object 
  



  

    

Pass the current value to the given block, replacing it with the block’s result. May retry if the value changes during the block’s execution.


  





  
Yields:


    
  
  • 
    (Object)
—    
    

    Calculate a new value for the atomic reference using given (old) value
    

    
  
    • 



Yield Parameters:


    
  
  • 
    old_value
    (Object)
—    
    

    the starting value of the atomic reference
    

    
  
    • 



Returns:





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end


  








  

    #value  ⇒ Fixnum 
  



  

    

Retrieves the current Fixnum value.


  





  
Returns:


    
  
  • 
    (Fixnum)
—    
    

    the current value
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end


  








  

    #value=(value)  ⇒ Fixnum 
  



  

    

Explicitly sets the value.


  





  
Parameters:


    
  
  • 
    value
    (Fixnum)
—    
    

    the new value to be set
    

    
  
    • 



Returns:


    
  
  • 
    (Fixnum)
—    
    

    the current value
    

    
  
    • 



Raises:


    
  
  • 
    (ArgumentError)
—    
    

    if the new value is not a Fixnum
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb', line 136



class AtomicFixnum < AtomicFixnumImplementation
  # @return [String] Short string representation.
  def to_s
    format '%s value:%s>', super[0..-2], value
  end

  alias_method :inspect, :to_s
end