Hexlet tests and linter status:

Data Validator

Data Validator is a Java library that helps you to validate some data types. The library supports three data types: Strings, Integers and Maps. To start to work with this just create a new Validator object and choose one of the proposed schemes:

var validator = new Validator();

StringSchema

This schema validate String objects. To choose this schema write:

var schema = validator.string();

StringSchema has three validation methods:

• required() - makes the fields required and limits the possibility to use null or empty String.
• minLength() - adds a minimum length constraint for the String. The String must be equal or longer than a specified number. Requires an integer parameter of minimum length.
• contains() - adds a String content constraint. The String must contain a substring passed in the method parameter.

Usage example:

StringSchema schema = validator.string().required().minLength(5).contains("hex");
schema.isValid(""); // false
schema.isValid("hex"); // false
schema.isValid("telxeh"); // false
schema.isValid("hexlet"); // true

NumberSchema

This schema validate Integer objects. To choose this schema write:

var schema = validator.number();

NumberSchema has three validation methods:

• required() - makes the fileds required and limits the possibility to use null.
• positive() - adds a constraint to use negative numbers.
• range() - adds a range constraint (inclusive). Requires two integer parameters of the first and the last numbers of range.

Usage example:

NumberSchema schema = validator.number().required().positive().range(2, 7);
schema.isValid(-5); // false
schema.isValid(8); // false
schema.isValid(5); // true
schema.isValid(7); // true

MapSchema

This schema validate Map objects. To schoose this schema write:

var schema = validator.map();

MapSchema has three validation methods:

• required() - makes the fields required and limits the possibility to use null.
• sizeOf() - adds a map size constraint. The K-V count must be equal to the number passed in the method parameter.
• shape() - adds constraints to map values. Accepts as a parameter a map of keys whose values need to be validated and schemas that would validate the values.

Usage example:

Map<String, BaseSchema> schemas = new HashMap<>();
schemas.put("name", validator.string().required());
schemas.put("age", validator.number().positive());

MapSchema schema = validator.map().sizeof(2).shape(schemas);

Map<String, Object> human1 = new HashMap<>();
human2.put("name", "");
human2.put("age", null);
schema.isValid(human1); // false

Map<String, Object> human2 = new HashMap<>();
human1.put("name", "Kolya");
human1.put("age", 100);
schema.isValid(human2); // true