CODEWITHSUNDEEP
javaconstructorargument-validation
me_digvijay
me_digvijay

Reputation: 5492

How to respond based on arguments in java constructor

I have a MVC type architecture for new user registration to my app. The user submits the registration form to the controller servlet. This servlet extracts the user parameters and passes them to a class constructor, which represents (and returns) a template(or dummy) user with all the fields initialized based on the arguments.

I remember people insisting on argument validation in methods or constructors before using them. Now I try to check the arguments for their validity(for example they are not null). So when I find any argument having invalid value, How do I notify the servlet that this particular argument is invalid, because I cannot return a value from the constructor.

Please help me.

Upvotes: 0

Views: 104

Answers (3)

Ajinkya
Ajinkya

Reputation: 22710

Validate before calling the constructor. If anything is wrong get back to user with error. If everything is fine then only call constructor and create objects.

Upvotes: 1

Jigar Joshi
Jigar Joshi

Reputation: 240870

You should use another service or some class to validate your data, and throw exception from method or pass message back to servlet

Upvotes: 1

Subin Sebastian
Subin Sebastian

Reputation: 10997

Do validation in servlet before calling the constructor. If validation fails forward to an error.jsp where you display which input parameter was null or invalid.

Upvotes: 0

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