Adding example of supervision-tree

For now built manually.

Author: pitr-ch

doc/actor/supervision_tree.in.rb

@@ -0,0 +1,70 @@
+require 'concurrent'
+
+logger                          = Logger.new($stderr) #
+Concurrent.configuration.logger = lambda do |level, progname, message = nil, &block|
+  logger.add level, message, progname, &block
+end #
+
+
+class Master < Concurrent::Actor::RestartingContext
+  def initialize
+    # for listener to be child of master
+    @listener = Listener.spawn(name: 'listener1', supervise: true, args: [self])
+  end
+
+  def on_message(msg)
+    case msg
+    when :listener
+      @listener
+    when :reset, :terminated, :resumed, :paused
+      log Logger::DEBUG, " got #{msg} from #{envelope.sender}"
+    else
+      pass
+    end
+  end
+
+  # TODO turn this into Behaviour and make it default part of RestartingContext
+  def on_event(event)
+    case event
+    when :resetting, :restarting
+      @listener << :terminate!
+    when Exception, :paused
+      @listener << :pause!
+    when :resumed
+      @listener << :resume!
+    end
+  end
+end #
+
+class Listener < Concurrent::Actor::RestartingContext
+  def initialize(master)
+    @number = (rand() * 100).to_i
+  end
+
+  def on_message(msg)
+    case msg
+    when :number
+      @number
+    else
+      pass
+    end
+  end
+
+end #
+
+master   = Master.spawn(name: 'master', supervise: true)
+listener = master.ask!(:listener)
+listener.ask!(:number)
+
+master << :crash
+
+sleep 0.1
+
+# ask for listener again, old one is terminated
+listener.ask!(:terminated?)
+listener = master.ask!(:listener)
+listener.ask!(:number)
+
+master.ask!(:terminate!)
+
+sleep 0.1

doc/actor/supervision_tree.out.rb

@@ -0,0 +1,74 @@
+require 'concurrent'                               # => true
+
+logger                          = Logger.new($stderr) 
+Concurrent.configuration.logger = lambda do |level, progname, message = nil, &block|
+  logger.add level, message, progname, &block
+end 
+
+
+class Master < Concurrent::Actor::RestartingContext
+  def initialize
+    # for listener to be child of master
+    @listener = Listener.spawn(name: 'listener1', supervise: true, args: [self])
+  end
+
+  def on_message(msg)
+    case msg
+    when :listener
+      @listener
+    when :reset, :terminated, :resumed, :paused
+      log Logger::DEBUG, " got #{msg} from #{envelope.sender}"
+    else
+      pass
+    end
+  end
+
+  # TODO turn this into Behaviour and make it default part of RestartingContext
+  def on_event(event)
+    case event
+    when :resetting, :restarting
+      @listener << :terminate!
+    when Exception, :paused
+      @listener << :pause!
+    when :resumed
+      @listener << :resume!
+    end
+  end
+end 
+
+class Listener < Concurrent::Actor::RestartingContext
+  def initialize(master)
+    @number = (rand() * 100).to_i
+  end
+
+  def on_message(msg)
+    case msg
+    when :number
+      @number
+    else
+      pass
+    end
+  end
+
+end 
+
+master   = Master.spawn(name: 'master', supervise: true)
+    # => #<Concurrent::Actor::Reference:0x7fbe491a71b0 /master (Master)>
+listener = master.ask!(:listener)
+    # => #<Concurrent::Actor::Reference:0x7fbe4919ceb8 /master/listener1 (Listener)>
+listener.ask!(:number)                             # => 92
+
+master << :crash
+    # => #<Concurrent::Actor::Reference:0x7fbe491a71b0 /master (Master)>
+
+sleep 0.1                                          # => 0
+
+# ask for listener again, old one is terminated
+listener.ask!(:terminated?)                        # => true
+listener = master.ask!(:listener)
+    # => #<Concurrent::Actor::Reference:0x7fbe49175bd8 /master/listener1 (Listener)>
+listener.ask!(:number)                             # => 99
+
+master.ask!(:terminate!)                           # => true
+
+sleep 0.1                                          # => 0