What is the best way to force a try block to break

Question

I have a try-catch block that I wish to break like a switch block but I couldn't find a recommended way of doing it. I'm fetching a lot of data in the try-catch block and wish to stop the fetching in between in case a certain condition is met. Just to get it working for now, I've deliberately forced the code to go into the catch block:

int i=0;
    try {
        //--do stuff----
        if(//-------is condition met?--------//)
            i = 1/0; // divide 1 by 0 -- a definite exception
    }
    catch (Exception e) {//---------do nothing---------//}

Is it safe to do this or should I go for another way?

EDIT:I'm fetching some xml data(actually, a lot). Depending on the internet connection, I need to stop the parsing after sometime(time-out) rather than go through the entire stream. I go through loops but I also make some calculations later. It doesn't make any sense to calculate with incomplete data, so I would prefer to just skip the whole thing.

Answer 1

It is not the try-catch that you should worry about breaking out of. From what I can tell, you are looking to do something along the lines of:

try
{
  // do thing 1

  // do thing 2

  if (!done)
  {
    // do thing 3

    // do thing 4

    if (still not done)
    {
      // do thing 5
    }
  }
} catch (Exception e)
{

}

If that is what you are trying to do, then that is probably how you should do it (instead of trying to escape from the try-catch). The other way is to shrink your try-catch blocks to surround each task individually.

If you provide more context to your question then it may be possible to provide a better answer.

Answer 2

If there is no other way you can use a block label

 load:{
      if(test)//skip the remaining load block
         break load;

  }

Otherwise you could refactor the loading code into a different method and return early.

Answer 3

Just throw whichever exception you want caught...

boolean stopLoop = false;
while (!stopLoop) {
    try {
        int key = Integer.parseInt(userInput);
        if (key > cutOff) throw new NumberFormatException();//<--like this
        else {
            System.out.println("Good job, your number didn't suck");
            //do some stuff...
            stopLoop = true;//<--End loop after some stuff
            //some more stuff, or..
            if(nomorestuff)break;//<--exit loop
        }
    catch (NumberFormatException nfe){
        System.err.println("Enter a number less than "+cutOff);
    }
}//end while

Answer 4

Do not use exceptions for non-exception error handling. This is likely a named anti-pattern. If so, I don't know the name.

Here is an example of breaking out of a loop when an exception is thrown and not using exception handling to perform non-exception error handling:

try
{
  while (... whatever ...)
  {
    ... do something that might throw a BlammoException.
  }
}
catch (BlammoException exception)
{
  ... handle the exception.
}