Resource4j library is a replacement for Java ResourceBundle mechanism that supports complex i18n scenarios of large and legacy applications and provides safe access to key/value application configuration and arbitrary resource files. With well-designed API based on fluent DSL it is a solution for i18n just like SLF4J is a solution for logging abstraction.

Key features of this library:

• Support of Java SE resource bundles, custom resource file formats (HOCON) and data sources (files, database etc).
• Fluent DSL for type conversions and enforcing not-null constraints
• Locale-based and custom resolution of values
• Spring Framework and Thymeleaf integration, including Spring EL and JavaConfig.
• Full support of Test-Driven Development
• Modular architecture allows to use only the part of implementation you really need

1. Add resource4j-core.jar to your classpath.
2. Create new instance of RefreshableResources:

Resources resources = new RefreshableResources();

3. Add resource bundles and content files to your classpath:

   /com/mycompany/data/Country-en_US.properties:
    discount=0.1
   
    # Formatting
    custom_format=MMMM d, yyyy
    today=Today is {date:custom_format}
   
    # Pluralization
    duration={count} {years;count:pluralize}
    years_one=year
    years_other=years
    

   /docs/EULA.txt:
    Lorem ipsum dolorem sit amet.

4. Get some value:

BigDecimal localDiscount = resources.get(key(Country.class, "discount"), in(Locale.US))
			.notNull()
			.as(BigDecimal.class); // 0.1

String date = resources.get(key(Country.class, "today"), in(Locale.US).with("date", LocalDate.of(2018, 1, 1)))
            .notNull()
            .asIs(); // "January 1, 2018"

String duration = resources.get(key(Country.class, "duration"), in(Locale.US).with("count", 3))
            .notNull()
            .asIs(); // "3 years"

5. Load content:

String eulaText = resources.contentOf("/docs/EULA.txt", in(Locale.US))
			.parsedTo(string())
			.asIs();

If you are using Maven, please, add following lines to your POM file:

	<dependency>
		<groupId>com.github.resource4j</groupId>
		<artifactId>resource4j-core</artifactId>
		<version>3.1.3</version>
	</dependency>

For integration with Spring and (optionally) Thymeleaf, add following:

	<dependency>
		<groupId>com.github.resource4j</groupId>
		<artifactId>resource4j-spring</artifactId>
		<version>3.1.3</version>
	</dependency>

For using Resource4j as message provider in Thymeleaf, add following:

	<dependency>
		<groupId>com.github.resource4j</groupId>
		<artifactId>resource4j-thymeleaf3</artifactId>
		<version>3.1.3</version>
	</dependency>

To add support of HOCON or XStream configuration files add Extras library:

    <dependency>
        <groupId>com.github.resource4j</groupId>
        <artifactId>resource4j-extras</artifactId>
        <version>3.1.3</version>
    </dependency>

1. Basics
2. Configuring resources
3. Integration with Spring Framework
4. Integration with Thymeleaf
5. Extras