Validation - S3nS3IW00/JCommands GitHub Wiki

InputArgument<I, O>'s input can be validated, and response can be set to every validation.

Validations in an argument stored in an ArgumentValidator<I> that has a generic value I that is the input type of the arugment. It can be accessed with InputArgument#getArgumentValidatior() method. To add new validator ArgumentValidator#when(Predicate<T>) or ArgumentValidator#when(ArugmentPredicate<T>) has to be called. The difference between the methods is that the first one excpects a java Predicate<T>, the second one expects an ArgumentPrediate<T> that has various types. Both of the methods return an ArgumentValidation<T> that stores the validation and provides the ArgumentValidation#thenRespond(ArgumentMismatchEventListener) method that handle the response to the validation when the predicate is true. Listener must be specified for every validation!

For example this validation limits the length of a String input type argument, and triggers when the length is not between 8 and 16 (inclusively):

argument.getArgumentValidator().when(value -> value.length() < 8 || value.length() > 16)
    .thenRespond(event -> {
        event.getResponder().respondNow()
            .setContent("Length must between 8 and 16!")
            .respond();
    });

Custom predicates that can be used to create more complex validations. Custom predicate can be created with implementing the ArgumentPredicate<T> functional interface with the input type as generic parameter.

As its name shows this can be used to validate a String input type argument by a regex pattern.

For example this argument accepts only numbers:

argument.getArgumentValidator().when(RegexPredicate.notValidFor("\\d+"))
    .thenRespond(event -> {
        event.getResponder().respondNow()
            .setContent("Input is not a number!")
            .respond();
    });

This predicate contains methods to validate a String input type argument by its length.

This predicate contains methods to validate a Long input type argument.