Created SerialExecutor 'type' module for interrogating objects.

Author: jdantonio

lib/concurrent/executor/executor.rb

@@ -5,9 +5,58 @@
 module Concurrent
 
   module Executor
+    
+    # @!macro [attach] executor_module_method_can_overflow_question
+    #
+    #   Does the task queue have a maximum size?
+    #
+    #   @return [Boolean] True if the task queue has a maximum size else false.
+    #
+    # @note Always returns `false`
     def can_overflow?
       false
     end
+
+    # @!macro [attach] executor_module_method_serialized_question
+    #
+    #   Does this executor guarantee serialization of its operations?
+    #
+    #   @return [Boolean] True if the executor guarantees that all operations
+    #     will be post in the order they are received and no two operations may
+    #     occur simultaneously. Else false.
+    #
+    # @note Always returns `false`
+    def serialized?
+      false
+    end
+  end
+
+  # Indicates that the including `Executor` or `ExecutorService` guarantees
+  # that all operations will occur in the order they are post and that no
+  # two operations may occur simultaneously. This module provides no
+  # functionality and provides no guarantees. That is the responsibility
+  # of the including class. This module exists solely to allow the including
+  # object to be interrogated for its serialization status.
+  #
+  # @example
+  #   class Foo
+  #     include Concurrent::SerialExecutor
+  #   end
+  #
+  #   foo = Foo.new
+  #
+  #   foo.is_a? Concurrent::Executor       #=> true
+  #   foo.is_a? Concurrent::SerialExecutor #=> true
+  #   foo.serialized?                      #=> true
+  module SerialExecutor
+    include Executor
+
+    # @!macro executor_module_method_serialized_question
+    #
+    # @note Always returns `true`
+    def serialized?
+      true
+    end
   end
 
   module RubyExecutor

lib/concurrent/executor/immediate_executor.rb

@@ -3,7 +3,7 @@
 
 module Concurrent
   class ImmediateExecutor
-    include Executor
+    include SerialExecutor
 
     def initialize
       @stopped = Concurrent::Event.new

lib/concurrent/executor/java_single_thread_executor.rb

@@ -6,6 +6,7 @@ module Concurrent
     # @!macro single_thread_executor
     class JavaSingleThreadExecutor
       include JavaExecutor
+      include SerialExecutor
 
       # Create a new thread pool.
       #

lib/concurrent/executor/java_thread_pool_executor.rb

@@ -90,6 +90,7 @@ def initialize(opts = {})
         set_shutdown_hook
       end
 
+    # @!macro executor_module_method_can_overflow_question
       def can_overflow?
         @max_queue != 0
       end

lib/concurrent/executor/ruby_single_thread_executor.rb

@@ -5,6 +5,7 @@ module Concurrent
   # @!macro single_thread_executor
   class RubySingleThreadExecutor
     include RubyExecutor
+    include SerialExecutor
 
     # Create a new thread pool.
     #

lib/concurrent/executor/ruby_thread_pool_executor.rb

@@ -100,6 +100,7 @@ def initialize(opts = {})
       @last_gc_time = Time.now.to_f - [1.0, (@gc_interval * 2.0)].max
     end
 
+    # @!macro executor_module_method_can_overflow_question
     def can_overflow?
       @max_queue != 0
     end