Java class for validating user input

Complex validations like the ones you explain are as good a candidate as any to be delegated to another class via composition.Remember though that validations can occur in different moments.With the exception of strings, if a user inputs the wrong type, the code will produce an exception and (if not handled correctly) will stop.The purpose of this code is to produce a consistent method to validate user input, and not let the program proceed until the user has inputted a correct type.Drawing used by permission of Dominik Joswig A Norwegian woman mistyped her account number on an internet banking system.Instead of typing her 11-digit account number, she accidentally typed an extra digit, for a total of 12 numbers.Then, before instantiating a validable object, I will execute the validation to prevent illegal values. Or just throw an exception if the validation fails?It seems to me the best option would be boolean returning methods and throw the exception when the object is instantianted, for example: It is OK to delegate any logic by means of composition if that logic is going to change dynamically during the execution of a program.

Failure to validate input can lead to serious security risks such as integer error, buffer overflow, and SQL injections among others.Most software packages rely on external input, either via the keyboard, network, or other external sources.Generally, this input will be of a specific type: for example, a user interface that requests a person’s name expects a series of alphabetic characters.This is the most basic solution anyone would follow, but this brings in a lot of overhead of code, time and effort.Imagine writing your validate method for a project that has over 100 models with 5 required fields in each of them.