Error Handling and ION Exceptions

ION Java User's Guide: Building ION Applets and Applications

Error Handling and ION Exceptions

When the ION Server detects an error, it throws an exception value you can detect and act upon using error-handling code. Consult the reference page for the method you are using to determine which exceptions ION can detect in a given situation.

Error handling is generally accomplished via a Java try/catch code segment. The following skeleton try/catch code illustrates how to catch exceptions and display an error message on the Java console. For a more detailed example, see Simple Applet Example.

Note
If an ION method (or any Java method, for that matter) throws a checked exception value, you must handle the exception in your code. The Java compiler will complain if you do not properly handle all possible exception values. Refer to a Java manual for more information on Java exception handling.

try{  
   some ION command  
}catch(IOException e) {  
   // IO Error  
      System.err.println("Error: Communication error:  
      "te.getMessage());  
      return;  
}catch( IONIllegalCommandException e){  
   // Illegal Command  
      System.err.println("Error: Illegal Command:  
      "te.getMessage());  
      return;  
}catch( IONSecurityException e){  
   // Security Violation  
      System.err.println("Error: Security Violation:  
      "te.getMessage());  
      return;  
   }  
}

IDL Online Help (March 06, 2007)