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@ControllerAdvice and Error Construction in Business Layer

Assume i have defined @ControllerAdvice

@ControllerAdvice
public class ErrorHandler {

// example
@ExceptionHandler(ParseException.class)
public void handleParseException(ParseException exception, HttpServletResponse response) {
// return response - error message, error description, error type (ERROR or EXCEPTION)
}
}
The problem is where i will formulate the error message text with parameters and also the message type - ERROR or EXCEPTION

Example, Assume file not found exception is thrown for the given file name

Generally, in message.properties file we will be having text as File Doesn't Exist for file {0}

The translation of error message usually happens in the presentation layer.....

Now if we need to pass the error message so that controller advice takes care of passing it to the UI....

Do we need to construct the error message in the service layer before sending ??? Where the exception and the parameters will be binded ???

for example

public void accessFile(String fileName) {
File file = new File(fileName);
if(!file.exists()) {
throw new FileNotFoundException(Constants.FILE_NOT_FOUND.....);
How to construct the error message with property key and sending with proper error message binded with exception???
so that in controller advice we would just use exception.getMessage() which will have the translated text.

}
}
Please let me know how to do it.

girionis

How to construct the error message with property key and sending with proper error message binded with exception???
so that in controller advice we would just use exception.getMessage() which will have the translated text.

Why not just do

if(!file.exists()) { 
   String msg = Properties.getMessage(Constants.FILE_NOT_FOUND);
   // then format the msg and replace the placeholder with the fileName
   // then throw an exception.
       throw new FileNotFoundException(msg); 
   }

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Software Programmer

ASKER

My problem is where to translate the message. Some says since i18n needs to be supported. It is always translate the message in the presentation layer instead of the backend.

I am planning to send the Constants.FILE_NOT_FOUND key string as well as the parameters as Object[] so that @ControllerAdvice translates using MessageSource and sends the text.

Is that would be a right approach ???

also, i would like to know how to send the response back to the front-end...When i catch the exception and sent a pojo object to the client.it says 500 error.

Do we need to set any status code to the response object ??? Basically i want the exception to be thrown to the user in the same dialog.

Assume a user submit a form and the exception should be shown in the dialog in the same form instead of re-directing to the error page.

SOLUTION

girionis

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Software Programmer

ASKER

I am not sure returning the status..Can we have as below

a. always return the response status as "SUCCESS"
b. send a reponse type a string variable as "ERROR" or "SUCCESS"
c. let AJAX takes the decision based on the response type

Please let me know what you say ???

ASKER CERTIFIED SOLUTION

girionis

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Software Programmer

ASKER

We have something like below....Please let me know whether this is the correct approach or wrong...Help me with the code snippet.

jQuery.ajax({
type:"post",
dataType:"json",
url: myAjax.ajaxurl,
data: {action: 'submit_data', info: info},
success: function(data) {
data.response.type == 'success' {
// success dialog
}
data.response.type == 'failure' {
// failure dialog
}
}
});

girionis

Yes this is correct.

Software Programmer

ASKER

Remember it doesn't have error function...Some says it is not the best practice...

Do we need to have error function or not ???

We have redundant code in the back-end...

Please analyse and comment..

girionis

What do you mean by "error function"?

Software Programmer

ASKER

success: function(data) {
.....
error:function(data)

girionis

I don't know how the error function is mapped on the front end. Is it called when it gets an error code (an HTTP status code starting with 5xx)?

Software Programmer

ASKER

Not sure..i will check and get back to you

girionis

Both are valid comments.