Renewed Interface Provider
Java lacks a way to inject objects into a class that have been provided as Service Provider Interface. tRip intent to help developers to create an already populated object from API implementations. Note that this not intent to provide a new Dependency Injection plataform, but an easy to use way to have loose coupling on your source code design. Please see more about SPI here.
Please consider the following StringGenerator interface. It intent to provide a simple way to generate Strings.
public interface StringGenerator {
String generate();
}Also, consider the following implementations of StringGenerator. The following class should be provided as defined in java.util.ServiceLoader documentation ( available here ).
public class HelloWorldGenerator implements StringGenerator {
public String generate() {
return "Hello World";
}
}The following Runnable will print twice generated data from injected StringGenerator.
@Log
public class TwicePrinterRunnable implements Runnable {
// Will be provided soon
@Provided StringGenerator generator;
@Override
public void run(){
log.info( generator.generate() );
log.info( generator.generate() );
}
}The bellow unit test is a simple way to see this example running.
public class SampleTest {
// Creating the Provider object
final Provider provider = new Provider();
@Test
public void seeItWorking(){
Runnable runnable = new TwicePrinterRunnable();
provider.provideOn( runnable );
runnable.run();
}
@Test
public void seeItWorkingIfTwicePrinterRunnableWasConfiguredAsRunnableProvider(){
Runnable runnable = provider.load( Runnable.class );
runnable.run();
}
}As a tiny implementation the above example doesn't show that is also possible to "inject" objects in a multi-level way. It means that, if the provided HelloWorldGenerator sample code depended ( in a hipotesis ) on a second interface implementation, and there was available a service implementation in the class path, so it would be "provided" as well.
Configuring a maven project is easy. Just include the following repository and dependency configuration on its respecitve places on your pom.xml.
...
<repository>
<id>texo-release-repository</id>
<name>Texo Release Repository</name>
<url>http://repository.texoit.com:8081/content/repositories/PublicRelease/</url>
</repository>
...
<dependency>
<groupId>com.texoit.trip</groupId>
<version>0.1</version>
<artifactId>trip-core</artifactId>
</dependency>
...rTip is Apache 2.0 licensed.