From: xaea alvein <ifxa3a@...>
Date: 2006-04-14T02:20:35+09:00
Subject: Re: do i have to use DRbUndumped?

maybe some code could illustrate better:

[assuming there is a TupleSpace-based name server and TupleSpace 
provider, like the one given in Mr. Eric Hodel's Ring example in his 
Segment7 site]

---
#HelloWorld.rb

class HelloWorld
	attr_writer :str
#	you can use DRbUndumped or the following.
#	either results in the same
	def initialize(str)
		@str = str
	end
	def _dump(*args, &block)
		Marshall.dump(@str, *args, &block)
	end
	def HelloWorld._load(*args, &block)
		HelloWorld.new(Marshall.load(*args, &block))
	end
	def to_s
		@str
	end
end

---
#Master.rb

require "rinda/ring"
require "HelloWorld"

DRb.start_service

ringServer = Rinda::RingFinger.primary
tupleSpace = ringServer.read([:name, :TupleSpace, nil, nil])[2]
tupleSpace = Rinda::TupleSpaceProxy.new tupleSpace

tupleSpace.write(["helloWorldObject", HelloWorld.new("Hello World!")])

DRb.thread.join

---
#Client1.rb

require "rinda/ring"
#require "HelloWorld"

DRb.start_service

ringServer = Rinda::RingFinger.primary
tupleSpace = ringServer.read([:name, :TupleSpace, nil, nil])[2]
tupleSpace = Rinda::TupleSpaceProxy.new tupleSpace

loop {
	aHelloWorldObject = tupleSpace.read(["helloWorldObject", nil])
	puts aHelloWorldObject[1]
}

---
#Client2.rb

require "rinda/ring"
#require "HelloWorld"

DRb.start_service

ringServer = Rinda::RingFinger.primary
tupleSpace = ringServer.read([:name, :TupleSpace, nil, nil])[2]
tupleSpace = Rinda::TupleSpaceProxy.new tupleSpace

aHelloWorldObject = tupleSpace.read(["helloWorldObject", nil])
aHelloWorldObject[1].str = "Goodbye!"

---

anyone can help me with HelloWorld's dumping alternative, or do i have o 
use DRbUndumped / pass-by-reference? i am expecting that each client 
gets a fresh copy of HelloWorld object, not a reference to it


xaea alvein wrote:

> 
> i guess i better give an example:
> 
> a master/server M has an object A that he want to put into tuplespace 
> (using write).
> a worker/client C1 wants to have a copy of the object A for himself to 
> work with (by using read, instead of take).
> a worker/client C2 also wants copy of object A (also using read).
> 
> the problem is, i currently only know that M have to use 
> DRb::DRbUndumped (or use the alternative dumping as listed in the first 
> reply of this topic by -a) if A is to be put into tuplespace, which is a 
> pass-by-reference, meaning that the copy of A that each client C1 and C2 
> has is actually the very same object currently residing in master M 
> (since the one put into the tuplespace is none other than DRbObject 
> reference to the object A)
> 
> what i need is that M to put exactly a copy of object A into the 
> tuplespace instead just a reference to the object A, and C1 and C2 to 
> each have the copy of the copy of object A that was previously inserted 
> into the tuplespace, so that if C1 or C2 each modifies the copy (of copy 
> of A, if that matters), it only appears to himself. this is what i 
> believe is a pass-by-value
> 

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