While working on https://jira.jboss.org/jira/browse/JBMESSAGING-1680, I need to create a thread and move some existing piece of code inside a method to that thread for concurrent execution. The method can be simplified as this:
public void methodA() throw Exception
{
doWork1();
doWork2();
}
doWork1() and doWork2() are two tasks independent of each other so they can be optimized using thread. So I plan to move doWork1() to another thread, like:
public void methodA() throw Exception
{
new Thread() { public void run() { doWork1(); } }.start();
doWork2();
}
The problems is that both doWork1() and doWork2() may throw Exception. So after my change, the doWork1() will be executed in a separate thread and it's exception will never be thrown from the calling thread of methodA(). To solve this, I uses a variable to hold the exception, like this:
public void methodA() throw Exception
{
final ExceptionHolder holder = new ExceptionHolder(); //a holder simply holds an exception reference.
new Thread() { public void run() {
try
{
doWork1();
}
catch (Exception e)
{
holder = e; //pass the exception to holder.
}
} }.start();
doWork2();
//here using join() to wait for the thread finish and then
if (holder.e != null)
{
throw holder.e;
}
}
I don't know if this is the proper way. But that's my current solution.
