Re: Antwort: Re: Return On Error

Posted by Daniel Hornung on
URL: http://imagej.273.s1.nabble.com/Return-On-Error-tp3690523p3690527.html

Michael Doube wrote:
> I like the idea but don't see it very often in other people's code.
>
> Perhaps an example would help to illustrate the technique, especially
> for those of us relatively new to Java, and who want to improve our skills?
>
> Michael

Real-life examples tend to be rather lengthy, but if you want to learn about
exceptions, this would be one possible starting point:

http://java.sun.com/docs/books/tutorial/essential/exceptions/index.html

I'll try a short example nonetheless:

public void run(ImageProcessor iProc)
{
  try{
    doTheRealStuff(iProc);
  } catch (MyEndpluginException e) {
    // oops, an exception was thrown,
    // so terminate the plugin now
    return;
  }
}

protected void doTheRealStuff(ImageProcessor iProc)
  throws MyEndpluginException
{
  // do the calculations here
  //...

  // unrecoverable problems found? throw an exception!
  if(problemSearching()) {
    throw new MyEndpluginException();
  }

  // no problem found? simply continue
  // ...

  someOtherMethod(); // if this one throws an exception, it is
                     // simply passed "upwards"
}

protected void someOtherMethod()
  throws MyEndpluginException
{
  // do more stuff here, including maybe throwing an exception
}

I hope this gives you a basic understanding,
Daniel

--
Daniel Hornung

Biomedical Physics Group
Max-Planck-Institute for Dynamics and Self-Organization
Bunsenstr. 10
D-37073 Goettingen

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