Exception Handling

Answers

• jeremydouglass

  April 2017 edited April 2017

  @jameswest -- you said:

  I'm wanting to wrap some int parsing in a try catch

  Without seeing your code (which you can share if you like) you probably want NumberFormatException. Here is a Java discussion that might be comparable to your Processing case:

  • http://stackoverflow.com/questions/6456219/java-checking-if-parseint-throws-exception

  In Processing, catch uses Java built-in exceptions. You can see this from the catch reference documentation

  • https://processing.org/reference/catch.html

  The catch keyword is used with try to handle exceptions. Sun's Java documentation defines an exception as "an event, which occurs during the execution of a program, that disrupts the normal flow of the program's instructions." [...] exception: the Java exception that was thrown

  Here is a general tutorial on Java exceptions and a list of the builtin exceptions:

  • https://www.tutorialspoint.com/java/java_exceptions.htm
  • https://www.tutorialspoint.com/java/java_builtin_exceptions.htm
• jameswest

  April 2017

  Thanks Jeremy most appreciated.. how much of Java is supported in Processing?
• jeremydouglass

  April 2017 edited April 2017

  @jameswest --

  The vast majority of Java is supported in Processing -- which is run through a pre-processor to be converted into Java when a sketch is built. You may import standard Java libraries, include pure Java tabs, and even write Processing sketches in full IDEs like Eclipse or Netbeans (with the proper setup and configuration).

  Every Processing sketch is actually a subclass of the PApplet Java class which implements most of the Processing language's features.

  When programming in Processing, all additional classes defined will be treated as inner classes when the code is translated into pure Java before compiling. This means that the use of static variables and methods in classes is prohibited unless you explicitly tell Processing that you want to code in pure Java mode.

  -- https://en.wikipedia.org/wiki/Processing_(programming_language)

  Example past discussion:

  • https://forum.processing.org/two/discussion/11632/whats-the-difference-between-processing-s-java-and-real-java
• GoToLoop

  April 2017 edited April 2017

  This means that the use of static variables and methods in classes is prohibited unless you explicitly tell Processing that you want to code in pure Java mode.

  We can use static members in a nested class in a ".pde" file as long as we declare it static as well. L-)

  Another way to get static members in nested classes is via extends.

  Notice also that inner classes can actually have static final fields declared inside it, as long as they're initialized w/ known compile-time constants! :-bd

  1. http://Docs.Oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.28
  2. https://Community.Oracle.com/thread/1252993
• Lord_of_the_Galaxy

  April 2017 edited April 2017

  Or, you can just catch the base class, Exception.

  try{
    //CODE
  }catch(Exception e){
    System.err.println(e.getLocalisedMessage());//maybe a Z instead of an S in Localised
    //e.printStackTrace()//if you want
  }