How do I cleanly catch Exceptions?

GLV

Hello,

I get a "java.net.UnknownHostException" in the example I provided if there is no network connection. In my full blown code I get a "NullPointerException" also displayed in the bar above console.

You have to disable network to see the error! The code works if there is a network connection and URL is correct and available and displays retrieved data in console.

If you click on sketch window it will loop() and you will try to access the url. I did this so you do not keep retrieving data in an endless loop!

My code works for what I am doing.

Is there a better way to catch an Exception such as this? And not fill console with an error message.

String text = "";
String url = null;

// Added missing code that was in a tab
XML xml;
boolean testNull = false;

public void setup() 
  {
  size(200, 200);     
  }

public void draw() 
  {
  url = "http://" + "www.yr.no/place/Ecuador/Galapagos/Seymour/forecast.xml";
  loadxml();
  noLoop();
  }

void mousePressed() 
  {
  loop();
  }

void loadxml()
  {
  try
    {
    xml = loadXML(url);
    }
  catch (NullPointerException nullPointer)
    {
    testNull = true;
    }   

    println(testNull);

  if (testNull == false)
    {  
  // Load the XML document
    xml = loadXML(url);  

    XML credit = xml.getChild("credit/link");
    println(credit.getString("text"));
    text = credit.getString("text");
    println(credit.getString("url"));
    url = credit.getString("url");  
    }
  else
    {
    text = ("Unavailable"); 
    url = ("Unavailable");
    println(text);
    println(url);
    }  
  }  

quark

If you want us to try your code you need to provide it all. You have a second tab but no code for it.

Chrisir

see technical faq in the forum

jeremydouglass

You may create a try with a series of catch checks if you wish to catch multiple exceptions in different circumstances on the same code.

You may also nest try-catch blocks if needed ( although it often isn't needed ).

kfrajer

Check the end of this post. It shows try with multiple catch statements: https://forum.processing.org/two/discussion/8072/what-is-an-exception-and-what-are-unhandled-exceptions

Kf

GLV

Thanks you for all the comments. I added missing lines of code. I will try some of the examples in suggestions.

For anyone looking for this: The "Technical FAQ" is on the "Frequently Asked Questions" post in "Recent Discussions":

https://forum.processing.org/two/discussion/8093/frequently-asked-questions#latest