JadConfig

JadConfig is a minimalistic annotation-driven configuration parsing framework for Java with minimal dependencies.

Example

Here is a quick example of a Java class used as configuration bean:

public class ConfigurationBean {
  @Parameter("my.stringList")
  public List<String> myList = new ArrayList<String>();

  @Parameter("my.integer")
  public int myInteger = 1;

  @Parameter(value = "my.uri", required = true)
  public URI myURI;
}

and how you initialize it with JadConfig:

ConfigurationBean bean = new ConfigurationBean();
new JadConfig(new PropertiesRepository("my.properties"), bean).process();

Assert.assertNotNull(bean.myList);

You can also use multiple repositories as source for your configuration (first match wins):

ConfigurationBean bean = new ConfigurationBean();
new JadConfig(
        Arrays.asList(
            new EnvironmentRepository(),
            new PropertiesRepository("my.properties")
        ),
        bean)
    .process();

Assert.assertNotNull(bean.myList);

Joda-Time

JadConfig optionally supports Joda-Time. In order to use it just add the Joda-Time dependency to your pom.xml:

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.9</version>
</dependency>

And register JodaTimeConverterFactory with the JadConfig instance:

JadConfig jadConfig = new JadConfig(repository, configurationBean);
jadConfig.addConverterFactory(new JodaTimeConverterFactory());
jadConfig.process();

Guava

JadConfig optionally supports some data types from Google Guava. In order to use it just add the Google Guava dependency to your pom.xml:

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>18.0</version>
</dependency>

And register GuavaConverterFactory with the JadConfig instance:

JadConfig jadConfig = new JadConfig(repository, configurationBean);
jadConfig.addConverterFactory(new GuavaConverterFactory());
jadConfig.process();

Currently the following data types are being supported:

CacheBuilderSpec
HashCode
HostAndPort
HostSpecifier
InternetDomainName
MediaType
UnsignedInteger
UnsignedLong

Guice

JadConfig optionally supports registering named bindings in Google Guice. In order to use it just add the Google Guice dependency to your pom.xml:

<dependency>
    <groupId>com.google.inject</groupId>
    <artifactId>guice</artifactId>
    <version>4.0</version>
</dependency>

And register NamedConfigParametersModule with the Guice Injector:

Injector injector = Guice.createInjector(new NamedConfigParametersModule(Collections.singleton(configurationBean)));

The name of the bindings are identical to the @Parameter name.

Example:

public class MyConfigBean {
    @Parameter("my.custom.config")
    public String customConfig;
}

// Create injector and register NamedConfigParametersModule.
// [...]

public class MyClass {
    @Inject
    public MyClass(@Named("my.custom.config") String customConfig) {
        // ...
    }
}

// MyClass will be instantiated with the value of customConfig from the MyConfigBean instance.
MyClass myClass = injector.getInstance(MyClass.class);

Please note that nullable properties which should be injected by Guice have to be annotated with @Nullable, see UseNullable in the Guice wiki for details.

Maven

To use JadConfig in your project using Maven add the following lines into the dependencies section of your pom.xml:

<dependency>
    <groupId>org.graylog</groupId>
    <artifactId>jadconfig</artifactId>
    <version>0.13.0</version>
</dependency>

Support

Please file bug reports and feature requests in GitHub issues.

License

JadConfig is being released under the Apache License, Version 2.0. You can download the complete license text at http://www.apache.org/licenses/LICENSE-2.0.html

Graylog2/JadConfig