question: private void checkFactoryClass ( @ NonNull TypeMirror factoryTypeMirror , @ NonNull TypeElement type ) { if ( seenFactoryTypeMirror == null ) { seenFactoryTypeMirror = factoryTypeMirror ; return ; } if ( ! types . isSameType ( factoryTypeMirror , seenFactoryTypeMirror ) ) { String errorMsg = "More than one factory class referenced by models " + seenFactoryTypeMirror . toString ( ) + " and " + factoryTypeMirror . toString ( ) ; abortWithError ( errorMsg , type ) ; } }
target:  Check to make sure there is only one factory class referenced.