CrossDial is a library for validating and formatting international phone numbers. It provides an easy-to-use interface for phone number validation with full error handling and batch support.

Table of Contents

1. What it Does
2. Getting Started
3. Usage
   • Validate a Single Phone Number
   • Validate Multiple Numbers (Batch Validation)
   • List Supported Countries
4. Understanding Validation Results
5. Common Error Types
6. Best Practices
7. Examples
   • Valid Number Formats
   • Error Handling Example
8. Thread Safety
9. Contributing
10. Acknowledgements

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What it Does

• Phone Number Validation: Validates individual phone numbers.
• Batch Validation: Supports validating multiple phone numbers at once.
• Phone Number Formatting: Formats phone numbers according to the E.164 standard.
• Detailed Error Reporting: Provides clear error messages for invalid numbers.
• Country Code Validation: Ensures the country code matches the phone number format.
• Thread-Safe: Designed to be thread-safe for use in multi-threaded environments.
• Error Handling: Handles errors using ValidationResult—no runtime exceptions.

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Getting Started

Maven

Add the following dependency to your pom.xml:

<dependency>
    <groupId>io.github.thesarfo</groupId>
    <artifactId>crossdial</artifactId>
    <version>1.0.0</version>
</dependency>

Gradle

Add this line to your build.gradle:

implementation group: 'io.github.thesarfo', name: 'crossdial', version: '1.0.0'

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Usage

Validate a Single Phone Number

PhoneNumberValidator validator = new PhoneNumberValidator();

ValidationResult result = validator.validateNumber("+233244444444", "GH");

if (result.isValid()) {
    System.out.println("Valid: " + result.getFormattedNumber());
} else {
    System.out.println("Invalid: " + result.getError().getMessage());
}

Validate Multiple Numbers (Batch Validation)

List<PhoneNumberRequest> numbers = Arrays.asList(
    new PhoneNumberRequest("+233244444444", "GH"),
    new PhoneNumberRequest("+1234567890", "US")
);

List<ValidationResult> results = validator.validateBatch(numbers);

results.forEach(r -> {
    if (r.isValid()) {
        System.out.println("Valid: " + r.getFormattedNumber());
    } else {
        System.out.println("Invalid: " + r.getOriginalNumber() + " - " + r.getError().getMessage());
    }
});

List Supported Countries

List<CountryCode> countries = validator.getSupportedCountries();
countries.forEach(c -> 
    System.out.println(c.getCountryName() + ": " + c.getCode())
);

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Understanding Validation Results

When you validate a phone number, you receive a ValidationResult object. Here’s how to use it:

• isValid(): Returns true if the phone number is valid.
• getFormattedNumber(): Returns the phone number formatted according to the E.164 standard.
• getOriginalNumber(): The phone number that was originally provided.
• getError(): If the number is invalid, this contains the error message.

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Common Error Types

The possible validation errors are encapsulated in an enum:

public enum ValidationError {
    INVALID_FORMAT("Invalid phone number format"),
    INVALID_COUNTRY_CODE("Invalid country code"),
    NUMBER_TOO_SHORT("Number is too short"),
    NUMBER_TOO_LONG("Number is too long"),
    EMPTY_NUMBER("Phone number cannot be empty"),
    PARSE_ERROR("Could not parse phone number")
}

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Best Practices

• Country Codes: Always use ISO 3166-1 alpha-2 country codes (e.g., “US”, “GB”, “GH”).
• Phone Numbers: Numbers can include or exclude the ‘+’ prefix, spaces, or dashes as necessary. The library will clean up the formatting.

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Examples

Valid Number Formats

validator.validateNumber("+1234567890", "US");
validator.validateNumber("123-456-7890", "US");

Error Handling Example

ValidationResult result = validator.validateNumber("123", "US");
if (!result.isValid()) {
    switch (result.getError()) {
        case NUMBER_TOO_SHORT -> System.out.println("Please enter a complete number");
        case INVALID_COUNTRY_CODE -> System.out.println("Invalid country code");
        default -> System.out.println("Error: " + result.getError().getMessage());
    }
}

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Thread Safety

CrossDial is thread-safe, so you can use it safely across multiple threads or as a singleton in your applications:

@Service
public class PhoneValidationService {
    private final PhoneNumberValidator validator = new PhoneNumberValidator();
    
    // Use the validator in your service methods
}

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Contributing

This project is meant to fit a very specific use case, but contributions are welcome. Feel free to open an issue or submit a pull request, or you can fork and build your own version

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Acknowledgements

This project was built on top of Google’s libphonenumber.