Unlike validation errors, which are generated during validation, invalid business state errors must be constructed manually.

In Commerce Engine, an invalid business state error is an Exception which implements the InvalidBusinessStateException interface. Each exception of type InvalidBusinessStateException can contain multiple StructuredErrorMessage objects, indicating why the failure state occurred.

For example, AvalabilityException is a fully constructed invalid business state error:

  public class AvailabilityException extends EpSystemException implements InvalidBusinessStateException {
      private final List<StructuredErrorMessage> structuredErrorMessages;
  
      public AvailabilityException(final String message, final Collection<StructuredErrorMessage> structuredErrorMessages) {
          super(message);
          this.structuredErrorMessages = structuredErrorMessages == null ? emptyList() : ImmutableList.copyOf(structuredErrorMessages);
      }
        
      @Override
      public List<StructuredErrorMessage< getStructuredErrorMessages() {
          return structuredErrorMessages;
      }
        
      @Override
      public String getExceptionMessage() {
          return getMessage();
      }   
  }            

For automatic InvalidBusinessStateException handling when calling a Commerce Engine service, use one of the fromService methods in ReactiveAdapter.

The following is an example of calling a Commerce Engine service with automatic exception handling of an InvalidBusinessStateExeption.

  Observable o = reactiveAdapter.fromService(() -> ceService.myMethod());   

If an exception occurs StructuredErrorMessage objects in the exception are converted to Message or LinkedMessage objects. These message objects are wrapped in a ResourceOperationFailure, and returned on the Rx type's error channel. This process is transparent to the user.

In addition to being consumable by Cortex, converting StructuredErrorMessage objects to Message or LinkedMessage allows these objects to contain information about links.