rosenfeld · June 7, 2016 12:49 · Jun 7, 2016
diff --git a/thread-pool.rb b/thread-pool.rb
@@ -0,0 +1,33 @@
+require 'thread' # for Mutex: Ruby doesn't provide out of the box thread-safe arrays
+
+class ThreadPool
+  def initialize(max_threads = 10)
+    @pool = SizedQueue.new(max_threads)
+    max_threads.times{ @pool << 1 }
+    @mutex = Mutex.new
+    @running_threads = []
+  end
+
+  def run(&block)
+    @pool.pop
+    @mutex.synchronize do
+      @running_threads << Thread.start do
+        begin
+          block[]
+        rescue Exception => e
+          puts "Exception: #{e.message}\n#{e.backtrace}"
+        ensure
+          @pool << 1
+        end
+      end
+    end
+  end
+
+  def await_completion
+    @running_threads.each &:join
+  end
+end
+
+pool = ThreadPool.new 5
+10.times {|i| pool.run{sleep 1} }
+pool.await_completion