Class: Brown::Agent::Memo

Inherits:
Object
  • Object
show all
Defined in:
lib/brown/agent/memo.rb

Overview

:nodoc: A thread-safe agent "memo".

This is the "behind the scenes" code that supports "agent memos", objects which are shared across all instances of a given agent.

All of the interesting documentation about how agent memos work is in ClassMethods.memo and ClassMethods.safe_memo.

Instance Method Summary collapse

Constructor Details

#initialize(blk, safe = false, test = false) ⇒ Memo

Spawn a new memo.



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# File 'lib/brown/agent/memo.rb', line 23

def initialize(blk, safe=false, test=false)
  @blk         = blk
  @value_mutex = Mutex.new
  @attr_mutex  = Mutex.new
  @safe        = safe
  @test        = test
end

Instance Method Details

#value(test = nil) {|Object| ... } ⇒ Object?

Retrieve the value of the memo.

Yields:

  • (Object) —

    the object which is the value of the memo.

Raises:

  • (RuntimeError) —

    if called on an unsafe memo without passing a block.



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# File 'lib/brown/agent/memo.rb', line 41

def value(test=nil)
  if block_given?
    @value_mutex.synchronize { yield cached_value }
    nil
  else
    if @safe || (@test && test == :test)
      cached_value
    else
      raise RuntimeError,
            "Access to unsafe agent variable prohibited"
    end
  end
end