JarCastingservice-binder
Injection parallel to the JDK ServiceLoader.
It comes in two flavors:
- Guice
- Spring Framework
Motivation
This section needs revision in light of non-support in Guice 3.0 of injecting modules.
Using ServiceLoader to find modules to install into Guice is straight-forward:
@Override
protected void configure() {
for (final Module : ServiceLoader.load(Module.class))
install(module);
}
However this does not provide modules with injection. Spring Framework handles this better.
Using ServiceBinder provides the same discovery mechanism and provides injection. It is not limited to modules.
Pick an injector
Use ServiceBinder.with(Binder) for Guice or [ServiceBinder.with(BeanDefinitionRegistry)] (src/main/java/hm/binkley/util/ServiceBinder.java#L77) for Spring Framework. These return an With implementation specific to your choice.
Bind services
Use With.bind(Class) or With.bind(Class, ClassLoader). If not provided bind() uses the thread-context class loader.
Examples
Examples assume these services:
public interface Bob {}
@MetaInfServices
public static final class Fred
implements Bob {}
@MetaInfServices
public static final class Nancy
implements Bob {
@Inject
public Nancy(@Named("cat-name") final String catName) {}
}
Guice example
public final class SampleModule
extends AbstractModule {
@Override
protected void configure() {
bindConstant().annotatedWith(named("cat-name")).to("Felix");
ServiceBinder.with(binder()).bind(Bob.class);
}
}
Spring example
@Configuration
public static class AppConfig {
@Bean(name = "cat-name")
public String catName() {
return "Felix";
}
}
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
context.register(AppConfig.class);
ServiceBinder.with(context).bind(Bob.class);
context.refresh();
Extras
You may find Kohsuke's META-INF/services generator useful to annotate your service implementations: it generates the META-INF services file for you.
When using the maven shade plugin you may also find [the services transformer] (https://maven.apache.org/plugins/maven-shade-plugin/examples/resource-transformers.html#ServicesResourceTransformer) useful to merge META-INF/services files.
Releases
0.3
- Use ServiceConfigurationError rather than ServiceBinderError
- Documentation
- Improved Spring unit tests
0.2
- Support for Guice
- Support for Spring Framework
0.1
Not released.