Question

How to make this algorithm better and working, where I am always ending up to reallyFail();. And I cannot let it in while loop for an unlimited amount of time, only for 5 minutes at most.

// This is a heavy rendering encryption which takes sometimes 1 minute 
// or sometimes
// it takes less then 1 seconds, very random to estimate to a fix time or delay
prepareEncoding(letter);

// Now once that is done i have two values which if null or empty 
// Goal can not be accomplished
if (main.myencryption0 != null && main.myencryption1 != null) {
  // Once those value are available
  // Proceed to he Goal
  prepareToGoal(letter);
} else {

  // Value is empty or null we do not know the status
  // We try for 3 times the same thing 
  // (i think this is wrong, but could not find alternative best way)
  for (int i = 0; main.myencryption0 == null && main.myencryption1 == null && i <= 3; ++i) {
    prepareEncoding(letter); 
  }

  // Wait still for few seconds to make 100% sure
  // We can not wait more then 5 minute, because its too long.
  try {
    Thread.sleep(3000);
  } catch (InterruptedException ex) {
    ex.printStackTrace();
  }  

  // Finally again check same thing do or die
  if (main.myencryption0 != null && main.myencryption1 != null) {
    prepareToGoal(letter);
  } else {
    reallyFail(); // OK - give up, drop the ball
  }

}

Answer 1

You can check the time with System.currentTimeMillis. So you can leave the while after 5 min.

long endTime = System.currentTimeMillis() + 300000; //After 5 min leave while loop

while (System.currentTimeMillis() < endTime 
  && main.myencryption0 == null
  && main.myencryption1 == null)
{
  prepareEncoding(letter); 

  try {
    Thread.sleep(1);
  } catch (InterruptedException ex) {
    ex.printStackTrace();
  }  
}

if (main.myencryption0 != null && main.myencryption1 != null) {
  prepareToGoal(letter);
} else {
  reallyFail(); // OK - give up, drop the ball
}