# Synchronized object **URL:** \ **Category:** ruby-talk\ **Created:** [21 April 2006 14:47 UTC](https://rubytalk.org/t/synchronized-object/26821 "2006-04-21T14:47:56Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Kroeger\_Simon\_ext](https://avatars.discourse-cdn.com/v4/letter/k/5daacb/32.png) [@Kroeger\_Simon\_ext](https://rubytalk.org/u/Kroeger_Simon_ext)\ **Post date:** [21 April 2006 14:47 UTC](https://rubytalk.org/t/synchronized-object/26821/1 "2006-04-21T14:47:56Z")
Dear ruby-talk, is there a nice, concise way to lock each and every method against all other methods of an object? To elaborate: I want to make sure that only one method of a specific object (not class) can run at a each point in time regardless of how many threads are using this object. I would hope there is module i just have to include in my class definition. cheers and thanks Simon ---
**Author:** ![Farrel\_Lifson](https://avatars.discourse-cdn.com/v4/letter/f/3da27b/32.png) [@Farrel\_Lifson](https://rubytalk.org/u/Farrel_Lifson)\ **Post date:** [21 April 2006 15:21 UTC](https://rubytalk.org/t/synchronized-object/26821/2 "2006-04-21T15:21:03Z")
You could have a class wide Mutex. class MyClass   @@mutex = Mutex.new   def atomicy\_method     @@mutex.synchronise do         # Code here     end   end end Farrel ---
**Author:** ![David\_Pollak1](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@David\_Pollak1](https://rubytalk.org/u/David_Pollak1)\ **Post date:** [21 April 2006 15:28 UTC](https://rubytalk.org/t/synchronized-object/26821/3 "2006-04-21T15:28:27Z")
Simon, Look at the Monitor module. For example: require 'monitor' class Foo   include MonitorMixin   def bar     self.synchronized do       # stuff     end   end   def baz     self.synchronized do       # more stuff     end   end end It's a little less syntactically sugary than Java, but about the same as C#. Do this help? Thanks, David > **···** > > On 4/21/06, Kroeger, Simon (ext) \ wrote: > > > Dear ruby-talk, > > > > is there a nice, concise way to lock each and > > every method against all other methods of an object? > > > > To elaborate: I want to make sure that only one method of > > a specific object (not class) can run at a each point in > > time regardless of how many threads are using this object. > > > > I would hope there is module i just have to include in > > my class definition. > > > > cheers and thanks > > > > Simon ---
**Author:** ![James\_Edward\_Gray\_II](https://avatars.discourse-cdn.com/v4/letter/j/ea5d25/32.png) [@James\_Edward\_Gray\_II](https://rubytalk.org/u/James_Edward_Gray_II)\ **Post date:** [21 April 2006 15:32 UTC](https://rubytalk.org/t/synchronized-object/26821/4 "2006-04-21T15:32:17Z")
You could wrap it in a delegate object you strip of methods, then just have method\_missing() forward the messages inside a synchronize block. James Edward Gray II > **···** > > On Apr 21, 2006, at 9:47 AM, Kroeger, Simon (ext) wrote: > > > Dear ruby-talk, > > > > is there a nice, concise way to lock each and > > every method against all other methods of an object? > > > > To elaborate: I want to make sure that only one method of > > a specific object (not class) can run at a each point in > > time regardless of how many threads are using this object. > > > > I would hope there is module i just have to include in > > my class definition. ---
**Author:** ![Logan\_Capaldo](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@Logan\_Capaldo](https://rubytalk.org/u/Logan_Capaldo)\ **Post date:** [21 April 2006 15:33 UTC](https://rubytalk.org/t/synchronized-object/26821/5 "2006-04-21T15:33:39Z")
Well it's not quite as easy as Java but: [http://www.ruby-doc.org/stdlib/libdoc/monitor/rdoc/index.html](http://www.ruby-doc.org/stdlib/libdoc/monitor/rdoc/index.html) obj.methods.each do |meth|     (class \<\< obj; self; end).module\_eval \<\ **···** > > On Apr 21, 2006, at 10:47 AM, Kroeger, Simon (ext) wrote: > > > Dear ruby-talk, > > > > is there a nice, concise way to lock each and > > every method against all other methods of an object? > > > > To elaborate: I want to make sure that only one method of > > a specific object (not class) can run at a each point in > > time regardless of how many threads are using this object. > > > > I would hope there is module i just have to include in > > my class definition. > > > > cheers and thanks > > > > Simon ---
**Author:** ![Andy\_Gimblett](https://avatars.discourse-cdn.com/v4/letter/a/8c91f0/32.png) [@Andy\_Gimblett](https://rubytalk.org/u/Andy_Gimblett)\ **Post date:** [21 April 2006 15:34 UTC](https://rubytalk.org/t/synchronized-object/26821/6 "2006-04-21T15:34:39Z")
If you want something like you get in Java with the "synchronized" keyword, that's a monitor, and the standard library includes (the not terribly well documented) monitor.rb: [http://www.ruby-doc.org/stdlib/libdoc/monitor/rdoc/](http://www.ruby-doc.org/stdlib/libdoc/monitor/rdoc/) (also [Monitor (synchronization) - Wikipedia](http://en.wikipedia.org/wiki/Monitor_%28synchronization%29) ) Whether it's nice or concise I don't know - it's certainly not a "one-liner" way to achieve what you want but it might get you a long way along the road. If you use it, I'd personally be interested in how you got on. (Caveat: I haven't used this, I just saw "synchronized object" in your subject line, thought "monitor", and searched the web for "ruby monitor synchronization" which led me to this info.) Hope this helps, -Andy > **···** > > On Fri, Apr 21, 2006 at 11:47:56PM +0900, Kroeger, Simon (ext) wrote: > > > Dear ruby-talk, > > > > is there a nice, concise way to lock each and every method against > > all other methods of an object? > > > > To elaborate: I want to make sure that only one method of a specific > > object (not class) can run at a each point in time regardless of how > > many threads are using this object. > > > > I would hope there is module i just have to include in my class > > definition. > > -- > Andy Gimblett > Computer Science Department > University of Wales Swansea > [http://www.cs.swan.ac.uk/~csandy/](http://www.cs.swan.ac.uk/~csandy/) ---
**Author:** ![David\_Corbin1](https://avatars.discourse-cdn.com/v4/letter/d/8491ac/32.png) [@David\_Corbin1](https://rubytalk.org/u/David_Corbin1)\ **Post date:** [22 April 2006 00:15 UTC](https://rubytalk.org/t/synchronized-object/26821/7 "2006-04-22T00:15:34Z")
It would be relatively easy to write a class that uses Monitor and delegates to specifc object. Thus, much like Java's Collections.synchronizedFoo, you could have Synchronizer.new(foo) that would synchronize ANY object. David > **···** > > On Friday 21 April 2006 10:47 am, Kroeger, Simon (ext) wrote: > > > Dear ruby-talk, > > > > is there a nice, concise way to lock each and > > every method against all other methods of an object? > > > > To elaborate: I want to make sure that only one method of > > a specific object (not class) can run at a each point in > > time regardless of how many threads are using this object. > > > I would hope there is module i just have to include in > > my class definition. > > > > cheers and thanks > > > > Simon ---
**Author:** ![Simon\_Kroger](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@Simon\_Kroger](https://rubytalk.org/u/Simon_Kroger)\ **Post date:** [21 April 2006 19:23 UTC](https://rubytalk.org/t/synchronized-object/26821/8 "2006-04-21T19:23:32Z")
Logan Capaldo wrote: > Well it's not quite as easy as Java but: > [http://www.ruby-doc.org/stdlib/libdoc/monitor/rdoc/index.html](http://www.ruby-doc.org/stdlib/libdoc/monitor/rdoc/index.html) > > obj.methods.each do |meth| >    (class \<\< obj; self; end).module\_eval \<\       def #{meth}(\*args, &block) >           self.synchronize { super } >       end > HERE > > end > > obj.extend(MonitorMixin) > > I did it in that order since I wouldn't want a synchronize { synchronize } accepted answer ... well kind of. 😉 running your code (with an empty array) gave me: ruby 1.8.4 (2005-12-24) [i386-mswin32] (eval):1: warning: redefining `\_\_send\_\_' may cause serious problem (eval):1: warning: redefining `\_\_id\_\_' may cause serious problem (eval):2:in `extend': undefined method `synchronize' for #\ (NoMethodError) but i got the right idea i think. My code now looks like: > **···** > > --------------------------------------------------------------------- > require 'monitor' > > def sync obj >   meth = obj.methods - %w{\_\_send\_\_ \_\_id\_\_} >   klass = class \<\< obj.extend(MonitorMixin); self; end >   meth.each{|m|klass.module\_eval "def #{m}(\*a,&b)synchronize{super}end"} >   obj > end > > --------------------------------------------------------------------- > > usage: > --------------------------------------------------------------------- > obj = sync() > obj.push 'a' > p obj > --------------------------------------------------------------------- > > and now that i see it, it looks quite simple 🙂 > > thanks to all of you who responded > > cheers > > Simon ---
**Author:** ![Patrick\_Hurley1](https://avatars.discourse-cdn.com/v4/letter/p/b77776/32.png) [@Patrick\_Hurley1](https://rubytalk.org/u/Patrick_Hurley1)\ **Post date:** [22 April 2006 02:54 UTC](https://rubytalk.org/t/synchronized-object/26821/9 "2006-04-22T02:54:14Z")
require 'monitor' class AutoMonitor   include MonitorMixin   def initialize(obj)     mon\_initialize     @obj = obj   end   def method\_missing(sym, \*args, &block)     synchronize do       @obj.send(sym, \*args, &block)     end   end end class Class   def monitored\_new(\*args, &block)     AutoMonitor.new(new(\*args, &block))   end end Something like this and then you can: f = Foo.monitored\_new pth > **···** > > On 4/21/06, David Corbin \ wrote: > > > On Friday 21 April 2006 10:47 am, Kroeger, Simon (ext) wrote: > > \> Dear ruby-talk, > > \> > > \> is there a nice, concise way to lock each and > > \> every method against all other methods of an object? > > \> > > \> To elaborate: I want to make sure that only one method of > > \> a specific object (not class) can run at a each point in > > \> time regardless of how many threads are using this object. > > > > \> I would hope there is module i just have to include in > > \> my class definition. > > \> > > \> cheers and thanks > > \> > > \> Simon > > > > It would be relatively easy to write a class that uses Monitor and delegates > > to specifc object. Thus, much like Java's Collections.synchronizedFoo, you > > could have > > > > Synchronizer.new(foo) that would synchronize ANY object. > > > > David ---
**Author:** ![Simon\_Kroger](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@Simon\_Kroger](https://rubytalk.org/u/Simon_Kroger)\ **Post date:** [22 April 2006 12:23 UTC](https://rubytalk.org/t/synchronized-object/26821/10 "2006-04-22T12:23:28Z")
Thanks a lot, but consider this: > **···** > > ------------------------------------------------------------------------- > require 'monitor' > > class AutoMonitor >   include MonitorMixin > >   def initialize(obj) >     mon\_initialize >     @obj = obj >   end > >   def method\_missing(sym, \*args, &block) >     synchronize do >       @obj.send(sym, \*args, &block) >     end >   end > end > > def sync obj >   meth = obj.methods - %w{\_\_send\_\_ \_\_id\_\_} >   klass = class \<\< obj.extend(MonitorMixin); self; end >   meth.each{|m|klass.module\_eval "def #{m}(\*a,&b)synchronize{super}end"} >   obj > end > > hash = {"test1" =\> 1, AutoMonitor.new("test2") =\> 2, sync('test3') =\> 3} > > p hash.include?("test1") #=\> true > p hash.include?(AutoMonitor.new("test1")) #=\> false > p hash.include?("test2") #=\> false > p hash.include?(AutoMonitor.new("test2")) #=\> false > > #but > > p hash.include?("test1") #=\> true > p hash.include?(sync("test1")) #=\> true > p hash.include?("test3") #=\> true > p hash.include?(sync("test3")) #=\> true > ------------------------------------------------------------------------- > > Of course it is possible to enhance AutoMonitor to handle these cases, > but i like the 4 liner. 🙂 > > If only i could make this module\_eval go away. (or at least use the > block form) > > cheers > > Simon > > Patrick Hurley wrote: > > > On 4/21/06, David Corbin \ wrote: > > [...] > > require 'monitor' > > > > class AutoMonitor > >   include MonitorMixin > > > >   def initialize(obj) > >     mon\_initialize > >     @obj = obj > >   end > > > >   def method\_missing(sym, \*args, &block) > >     synchronize do > >       @obj.send(sym, \*args, &block) > >     end > >   end > > end > > > > class Class > >   def monitored\_new(\*args, &block) > >     AutoMonitor.new(new(\*args, &block)) > >   end > > end > > > > Something like this and then you can: > > > > f = Foo.monitored\_new > > > > pth