Class: Universa::LazyValue

Inherits:
Object
  • Object
show all
Defined in:
lib/universa/lazy.rb

Overview

Experimental!

Memoizable lazy pattern. A value that is calculated only once and onlywhen first time #get is called. LazyValue is thread-safe and calculates its value exactly once.

Instance Method Summary collapse

Constructor Details

#initialize(&block) ⇒ LazyValue

initialize lazy value with an optional initializer block. If no initializer block is given, then #get call must provide one.



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# File 'lib/universa/lazy.rb', line 11

def initialize(&block)
  @value = nil
  @ready = false
  @initializer = block
  @mutex = Mutex.new
end

Instance Method Details

#clear ⇒ Object

causes value to be recalculated on next call to #get



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# File 'lib/universa/lazy.rb', line 34

def clear
  @ready = false
end

#get(&block) ⇒ Object

Get the value, calculating it using initializer block specified in the params or at creation time if no block is provided



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# File 'lib/universa/lazy.rb', line 20

def get(&block)
  @mutex.synchronize {
    if @ready
      @value
    else
      @initializer = block if block
      @value = @initializer.call
      @ready = true
      @value
    end
  }
end