Class Rinda::RingFinger
In: lib/rinda/ring.rb
Parent: Object

RingFinger is used by RingServer clients to discover the RingServer‘s TupleSpace. Typically, all a client needs to do is call RingFinger.primary to retrieve the remote TupleSpace, which it can then begin using.

Methods

each   finger   lookup_ring   lookup_ring_any   new   primary   to_a   to_a  

Attributes

broadcast_list  [RW]  The list of addresses where RingFinger will send query packets.
port  [RW]  The port that RingFinger will send query packets to.
primary  [RW]  Contain the first advertised TupleSpace after lookup_ring_any is called.

Public Class methods

finger()

Creates a singleton RingFinger and looks for a RingServer. Returns the created RingFinger.

[Source]

     # File lib/rinda/ring.rb, line 106
106:     def self.finger
107:       unless @@finger 
108:         @@finger = self.new
109:         @@finger.lookup_ring_any
110:       end
111:       @@finger
112:     end
new(broadcast_list=@@broadcast_list, port=Ring_PORT)

Creates a new RingFinger that will look for RingServers at port on the addresses in broadcast_list.

[Source]

     # File lib/rinda/ring.rb, line 147
147:     def initialize(broadcast_list=@@broadcast_list, port=Ring_PORT)
148:       @broadcast_list = broadcast_list || ['localhost']
149:       @port = port
150:       @primary = nil
151:       @rings = []
152:     end
primary()

Returns the first advertised TupleSpace.

[Source]

     # File lib/rinda/ring.rb, line 117
117:     def self.primary
118:       finger.primary
119:     end
to_a()

Contains all discovered TupleSpaces except for the primary.

[Source]

     # File lib/rinda/ring.rb, line 124
124:     def self.to_a
125:       finger.to_a
126:     end

Public Instance methods

each() {|@primary| ...}

Iterates over all discovered TupleSpaces starting with the primary.

[Source]

     # File lib/rinda/ring.rb, line 164
164:     def each
165:       lookup_ring_any unless @primary
166:       return unless @primary
167:       yield(@primary)
168:       @rings.each { |x| yield(x) }
169:     end
lookup_ring(timeout=5, &block)

Looks up RingServers waiting timeout seconds. RingServers will be given block as a callback, which will be called with the remote TupleSpace.

[Source]

     # File lib/rinda/ring.rb, line 176
176:     def lookup_ring(timeout=5, &block)
177:       return lookup_ring_any(timeout) unless block_given?
178: 
179:       msg = Marshal.dump([[:lookup_ring, DRbObject.new(block)], timeout])
180:       @broadcast_list.each do |it|
181:         soc = UDPSocket.open
182:         begin
183:           soc.setsockopt(Socket::SOL_SOCKET, Socket::SO_BROADCAST, true)
184:           soc.send(msg, 0, it, @port)
185:         rescue
186:           nil
187:         ensure
188:           soc.close
189:         end
190:       end
191:       sleep(timeout)
192:     end
lookup_ring_any(timeout=5)

Returns the first found remote TupleSpace. Any further recovered TupleSpaces can be found by calling to_a.

[Source]

     # File lib/rinda/ring.rb, line 198
198:     def lookup_ring_any(timeout=5)
199:       queue = Queue.new
200: 
201:       th = Thread.new do
202:         self.lookup_ring(timeout) do |ts|
203:           queue.push(ts)
204:         end
205:         queue.push(nil)
206:         while it = queue.pop
207:           @rings.push(it)
208:         end
209:       end
210:       
211:       @primary = queue.pop
212:       raise('RingNotFound') if @primary.nil?
213:       @primary
214:     end
to_a()

Contains all discovered TupleSpaces except for the primary.

[Source]

     # File lib/rinda/ring.rb, line 157
157:     def to_a
158:       @rings
159:     end

[Validate]