The Folder Listing web script validates that the provided folder path actually exists in the repository using the following code pattern:
...
if (folder == null)
{
throw new WebScriptException(Status.STATUS_NOT_FOUND,
"Folder " + folderPath + " not found");
}
...
The WebScriptException class is a special kind of exception supported by the Web Script Framework, which carries a status code and message. Whenever a web script throws this kind of exception, the Web Script Framework translates it into the equivalent status on the HTTP response. All other exceptions are caught by the Web Script Framework and translated into the 500 status code, which means an internal error occurred. In all cases, the status response template has access to details such as the status code, status message, and exception call stack. Throwing an exception is not always ideal, so the Web Script Framework provides another approach to setting the response status code. The executeImpl() method is passed a Status object, which allows the web script to set the status explicitly.
Your Folder Listing Web script can implement folder validation using the following alternate code:
...
if (folder == null)
{
status.setCode(Status.SC_NOT_FOUND);
status.setMessage("Folder " + folderPath + " not found");
status.setRedirect(true);
return;
}
...
One advantage of setting the status explicitly is that the web script can control whether a status response template is used to render the status through the setRedirect() method. Exceptions can be handled in a similar manner:
...
catch(ConstraintException e)
{
status.setCode(Status.SC_FORBIDDEN);
status.setMessage("Cannot create folder");
status.setException(e);
status.setRedirect(true);
}
...
The setException() method allows the web script to associate the status with the caught exception.