Setting a custom exception handler

You can set an exception handler to customize exception handling in rule conditions and actions. When you implement the CustomExceptionHandler API, exceptions can either be ignored or rethrown.

1. Implement the CustomExceptionHandler interface in the XOM. In the following example, the custom exception handler rethrows exceptions for NumberFormatException:

   package com.acme;
   import ...
   
   public class MyCustomExceptionHandler implements CustomExceptionHandler {
   
     static Logger logger = Logger.getLogger(MyCustomExceptionHandler.class.getName());
   
     /**
      * The custom exception handler must contain a default constructor.
      */
     public MyCustomExceptionHandler() {
     }
   
     @Override
     public void handleConditionException(Exception e) throws Exception {
       if (e instanceof NumberFormatException) {
         // ignore number format exception
       } else {
         // rethrow the exception, it will stop the engine execution
         throw e;
       }
     }
   
     @Override
     public void handleActionException(Exception e, RuleInstance ruleInstance) throws Exception {
       if (e instanceof NumberFormatException) {
         // ignore number format exception and log
         if (logger.isLoggable(Level.INFO)) {
           logger.log(Level.INFO,
               "Exception while executing action of rule " + ruleInstance.getRuleName(), e);
         }
       } else {
         // rethrow the exception, it will stop the engine execution
         throw e;
       }
     }
   }

2. Open Rule Designer.
3. In the Rule Engine panel of the rule project properties window, enter the custom exception handler name. For example, enter com.acme.MyCustomExceptionHandler in the Custom exception handler field.
4. Click OK.