slim-validator

A lightweight, annotation-driven Java validation library with zero dependencies.
Easily validate your POJOs using simple annotations like @NotNull, @Min, @Max, @Pattern, @Email, and @Length.

More features will be integrated soon.

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🚀 Features

• Annotation-based validation — simple and clear
• Supported annotations:
  • @NotNull — null check
  • @Min / @Max — numeric boundaries
  • @Pattern — regex pattern validation
  • @Email — email format validation
  • @Length — string length constraints
  • @NotBlank — string null, empty and only whitespace check
  • @Past and @Future — date check
• Performance optimized — reflection access is cached
• Easy integration — just annotate your POJOs and call the validator
• Open source — community-driven and extendable

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💡 Usage

1. Define your POJO

public class UserDto {
    @NotNull(message = "Email cannot be null")
    @Email(message = "Email format is invalid")
    private String email;

    @Min(value = 18, message = "Age must be at least 18")
    @Max(value = 99, message = "Age must be less than 100")
    private Integer age;

    @Length(min = 2, max = 3, message = "Country code length must be between 2 and 3")
    private String countryCode;

    // getters and setters
}

2. Validate your object

SlimValidator validator = new SlimValidator();

UserDto userDto = new UserDto();
userDto.setAge(12);
userDto.setCountryCode("US");
userDto.setEmail("email@example.com");

validator.validate(userDto); // throws ValidationException on failure

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📦 Central Repository

• Maven (Latest Version)

<dependency>
  <groupId>io.github.arasdenizhan</groupId>
  <artifactId>slim-validator</artifactId>
  <version>1.2.0</version>
</dependency>

• Gradle (Latest Version)

implementation group: 'io.github.arasdenizhan', name: 'slim-validator', version: '1.2.0'

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🛠️ Development

• Easily add new annotations and validation strategies
• Extensible architecture based on StrategyFactory
• Reflection caching for optimal performance

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📚 Documentation

The full API documentation is available at:

👉 Javadoc for Slim Validator

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📚 Benchmark Chart

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📄 License

Apache License 2.0 (Open source and free to use)

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🤝 Contribution

Pull requests and issues are welcome!

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Contact

Denizhan Aras — github.com/arasdenizhan