Scheduled flow of tasks
<p>I need to create a scheduled task of retrieving data from somewere and then perform parsing -->then manipulations --> then creating output file --> then sending output file </p>

<p>I would like to use 5 working classes: MainExecutor class, Retriever class, Reader class, Builder class, Sender class
The main MainExecutor class would use <em>ScheduledThreadPoolExecutor</em> for scheduling the Retriever.</p>

<p>I would like to make this app scalable. Do I need to make each of these classes (Reader, Builder, Sender) a separate thread?</p>

<p>Do I need to use a thread pool for each of them?</p>

<p>What is the best way to implement this program?</p>
