Class: Archipelago::Tranny::TransactionProxy

Inherits:
Object
  • Object
show all
Defined in:
lib/archipelago/tranny.rb

Overview

A proxy to a transaction managed by this manager.

Used because standard DRbObjects only use object_id to identify objects, while we want the more unique transaction_id.

Will also remember the state of the transaction when it detects methods that will terminate it (:commit | :abort).

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(transaction) ⇒ TransactionProxy

Returns a new instance of TransactionProxy.



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# File 'lib/archipelago/tranny.rb', line 183

def initialize(transaction)
  @manager = transaction.manager
  @manager_id = transaction.manager.service_id
  @transaction_id = transaction.transaction_id
  @state = :unknown
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth, *args) ⇒ Object

Forwards everything to our Transaction and remembers returnvalue if necessary.



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# File 'lib/archipelago/tranny.rb', line 228

def method_missing(meth, *args) #:nodoc:
  rval = nil
  begin
    rval = @manager.call_instance_method(@transaction_id, meth, *args)
  rescue DRb::DRbConnError => e
    if defined?(Archipelago::Disco::MC)
      possible_replacements = Archipelago::Disco::MC.lookup(Archipelago::Disco::Query.new({:service_id => @manager_id}))
      raise e if possible_replacements.empty?
      
      @manager = possible_replacements[@manager_id][:service]
      
      retry
    else
      raise e
    end
  end
  case meth
  when :abort!
    @state = :aborted
  when :commit!
    @state = rval
  end
  return rval
end

Instance Attribute Details

#transaction_id ⇒ Object

Returns the value of attribute transaction_id.



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# File 'lib/archipelago/tranny.rb', line 182

def transaction_id
  @transaction_id
end

Instance Method Details

#==(o) ⇒ Object

Implemented to allow comparison between proxies.



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# File 'lib/archipelago/tranny.rb', line 221

def ==(o)
  eql?(o)
end

#eql?(o) ⇒ Boolean

Implemented to ensure that all TransactionProxies with the same transaction_id are hashwise equal.

Returns:

  • (Boolean) 


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# File 'lib/archipelago/tranny.rb', line 211

def eql?(o)
  if TransactionProxy === o
    o.transaction_id == @transaction_id
  else
    false
  end
end

#hash ⇒ Object

Implemented to ensure that all TransactionProxies with the same transaction_id are hashwise equal.



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# File 'lib/archipelago/tranny.rb', line 204

def hash
  @transaction_id.hash
end

#state ⇒ Object

Return the cached state of the wrapped Archipelago::Tranny::Transaction if it is known, otherwise fetch it.



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# File 'lib/archipelago/tranny.rb', line 193

def state
  if @state == :unknown
    method_missing(:state)
  else
    @state
  end
end