Data validator

Description

Data validator is a library which helps to check the correctness of data.
It can be used for strings, integer numbers and maps.

How to use

Create Validator object and define validation scheme by using string(), number() or map().
Example:

import hexlet.code.Validator;
import hexlet.code.schemas.StringSchema;

Validator v = new Validator();
StringSchema schema = v.string();

There are methods for each data type to add some limitations. After the scheme is customized, isValid() method shows if the data is correct.

String validation

• required() — string should be non-empty (does not equal null or "")
• minLength() — string's length should be equal or more than specified number
• contains() — string should contain specified substring

Example:

import hexlet.code.Validator;
import hexlet.code.schemas.StringSchema;

Validator v = new Validator();
StringSchema schema = v.string();

schema.isValid(""); // true
schema.isValid(null); // true

schema.required();
schema.isValid("what does the fox say"); // true
schema.isValid("hexlet"); // true
schema.isValid(null); // false
schema.isValid(5); // false
schema.isValid(""); // false

schema.contains("wh").isValid("what does the fox say"); // true
schema.contains("what").isValid("what does the fox say"); // true
schema.contains("whatthe").isValid("what does the fox say"); // false

schema.isValid("what does the fox say"); // false

Number validation

• required() — number should be not null
• positive() — number should be positive
• range() — number should fit in specified range

Example:

import hexlet.code.Validator;
import hexlet.code.schemas.NumberSchema;

Validator v = new Validator();

NumberSchema schema = v.number();

schema.isValid(null); // true
schema.positive().isValid(null); // true

schema.required();

schema.isValid(null); // false
schema.isValid("5"); // false
schema.isValid(10) // true

schema.isValid(-10); // false
schema.isValid(0); // false

schema.range(5, 10);

schema.isValid(5); // true
schema.isValid(10); // true
schema.isValid(4); // false
schema.isValid(11); // false

Map validation

• required() — value should be not null, only map fits to this limitation
• sizeof() — map should have the exact amount of key-value pairs

Example:

import hexlet.code.Validator;
import hexlet.code.schemas.MapSchema;

Validator v = new Validator();

MapSchema schema = v.map();

schema.isValid(null); // true

schema.required();

schema.isValid(null) // false
schema.isValid(new HashMap()); // true
Map<String, String> data = new HashMap<>();
data.put("key1", "value1");
schema.isValid(data); // true

schema.sizeof(2);

schema.isValid(data);  // false
data.put("key2", "value2");
schema.isValid(data); // true

Nested data validation

• shape() — allows to add limitations for values inside maps

import hexlet.code.Validator;
import hexlet.code.schemas.MapSchema;
import hexlet.code.schemas.BaseSchema;

Validator v = new Validator();

MapSchema schema = v.map();

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

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

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

Map<String, Object> human3 = new HashMap<>();
human3.put("name", "");
human3.put("age", null);
schema.isValid(human3); // false

Map<String, Object> human4 = new HashMap<>();
human4.put("name", "Valya");
human4.put("age", -5);
schema.isValid(human4); // false