Class: Memoizable::Memory

Inherits:
Object
  • Object
show all
Defined in:
lib/memoizable/memory.rb

Overview

Storage for memoized methods

Instance Method Summary collapse

Constructor Details

#initialize ⇒ undefined

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Initialize the memory storage for memoized methods



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# File 'lib/memoizable/memory.rb', line 13

def initialize
  @memory  = ThreadSafe::Cache.new
  @monitor = Monitor.new
  freeze
end

Instance Method Details

#[](name) ⇒ Object

Get the value from memory

Parameters:

  • name (Symbol)

Returns:

  • (Object) 


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# File 'lib/memoizable/memory.rb', line 26

def [](name)
  @memory.fetch(name) do
    fail NameError, "No method #{name} is memoized"
  end
end

#[]=(name, value) ⇒ undefined

Store the value in memory

Parameters:

  • name (Symbol)
  • value (Object)

Returns:

  • (undefined) 


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# File 'lib/memoizable/memory.rb', line 40

def []=(name, value)
  memoized = true
  @memory.compute_if_absent(name) do
    memoized = false
    value
  end
  fail ArgumentError, "The method #{name} is already memoized" if memoized
end

#fetch(name) ⇒ Object

Fetch the value from memory, or store it if it does not exist

Parameters:

  • name (Symbol)

Yield Returns:

  • (Object) —

    the value to memoize



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# File 'lib/memoizable/memory.rb', line 57

def fetch(name)
  @memory.fetch(name) do       # check for the key
    @monitor.synchronize do    # acquire a lock if the key is not found
      @memory.fetch(name) do   # recheck under lock
        self[name] = yield     # set the value
      end
    end
  end
end

#key?(name) ⇒ Boolean

Test if the name has a value in memory

Parameters:

  • name (Symbol)

Returns:

  • (Boolean) 


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# File 'lib/memoizable/memory.rb', line 74

def key?(name)
  @memory.key?(name)
end