Re: [Repast-developer] DataRecorder and thread saftey

[Mark R. D. <mdi...@la...>]

I was actually working one the idea of having a "DataRecorder" available 
across Simulation Threads. The idea is that since I've moved my batch 
processing up and out of the Repast Controller API, I'm now handing an 
already existing instance of a my Recording Class into the 
Controller/Model pair I'm runinng. I havn't encountered an issue where 
threading would be a problem, but where I'm heading could invlove 
multiple simulations running at the same time on different threads, 
thread saftey could be benificial. Sadly, I ended up just writing a 
class BatchRecorder that wraps a FileWriter, not that its a 
"DataRecorder". While I understand the concepts behind "DataRecorder" I 
wanted a little more control over the header and record layout than I 
could get in the DataRecorder, so I ended up rolling my own.

Thomas R. Howe wrote:

>Funny you should ask, because I'm facing the same issue as I am writing
>the DistributedDataRecorder.  The classes are not thread safe.  I need
>to warn you, As I'm writing the distributed stuff, I will probably turn
>DataRecorder into a Proxy for either a distributed or a local
>DataRecorder.  This won't affect most people, but perhaps it will for
>what you are doing.
>  
>
Not to sound like an "Interface junkie" but would it be good to place 
the DataRecorder behind a "Recorder" interface. Instead of thinking of 
 it as a proxy, produce separate DistributedDataRecorder and 
DataRecorder implementations of the Recorder Interface? Then The 
DataRecorder can stay in its current state and New Implementations (like 
DistributedDataRecorder) can be created by developers. 

I guess in the case where a Model might have a "Recorders" collection 
that any recorder can be added into, then data collection just becomes 
an issue of calling Recorder.record()/Recorder.writeToFile() on the 
objects in the collection.

I.E.

List recorders = new ArrayList();

recorders.add(new DataRecorder(...));
recorders.add(new DistributedDataRecorder(...));

ActionGroup group = new ActionGroup(ActionGroup.SEQUENTIAL);
group.createActionForEach(recorders, uchicago.src.sim.analysis.Recorder 
, "record");
group.createActionForEach(recorders, uchicago.src.sim.analysis.Recorder 
, "writeToFile");

schedule.scheduleActionBeginning(0.0,group);

-Mark