Gson Validation

Validate objects before converting to json

Gson is an annotation based validation library used to validate java objects when converting to and from json strings using google's gson library.

Use annotations to seperate validation logic from rest of your code
Simple and lightweight library which doesn't get in the way
Easy to and add custom annotations to fit your needs.

Installation

For now maven isn't supported, you can use jitpack but I would reccomend downloading as a jar and adding to your build path

Development

Start by adding validation annotations to java fields.

class BasicObject {
    @Required
    String field;
    @Email
    String email;
}

Then when validating the class, use the method GsonValidation#validate(Object obj);

BasicObject obj = new BasicObject();
obj.field = "value";
obj.email = 'email@example.com';

GsonValidator validator = new GsonValidator(obj);
List<String> errors = validator.validate().catchErrors();

Annotations

@Email - Validate an email. @Required - Makes the field required. Field cannot be missing. @PhoneNumber - Validate a phone number @Size(int min, int max) - Limit the min and max size of a number or string. Defaults are lowest/highest value for that data type. @Regex(String regex) - Run the validation tests against custom regex. Works on Strings only.

To make all fields required, enable requiredFields in the config

Methods

ValidationBuilder GsonValidator#validate(Object); //validates object to json
String ValidationBuilder#toJson() throws ValidationException; //converts the data to json
List<String> ValidationBuilder#validate(String, Class); //validates json to object

License

MIT