Singleton or static

[Deepak Chopra]

Hi All,

I am doing some development work in which i am making one class file which will do the validation of method arguments.
i am confuse How should i design this class?
Whether i make this class as singleton and then call its non static method OR
make this class as normal and make the methods as static?

Can someone tell which will be the better option?
Is there any other alternative to this?

[marc weber]

I think it depends on how the validation works. For example, if validation might be specific to instances, then you might want this to be neither static nor a singleton.

What are some of the factors you're considering?

[Deepak Chopra]

Actually the module i am developing a module, it will be having around 50 classes, and around 200 methods. so instead of validating method argument in every method, i want to make a class which will do it. So i will call its method from every method in another classes. So I have following options:

either create a different Object of validation class every time or
Make the validation class a singleton class or
make the validation method as static.

I was thinking its not good to create a new Validation class Object every time
i want to validation something.

[Garrett Rowe]

I agree with marc, furthermore I could see a case for making a Validator object a field of the class. It seems to me that different use cases could have different validation rules that are such that you would need to configure them before hand.

interface Validator<T> {
   void validate(T arg) throws ValidationException
}
 
//...
 
Validator<Object> objectValidator = new ValidatorBuilder<Object>()
                                       .notNull()
                                       .toValidator();
 
Validator<String> stringValidator =  new ValidatorBuilder<String>()
                                       .notNull()
                                       .notEquals("")
                                       .toValidator();
 
Validator<Integer> integerValidator =  new ValidatorBuilder<Integer>()
                                          .notNull()
                                          .inRange(0, Integer.MAX_VALUE)
                                          .toValidator();