Testing OSGi components - JUnit in Action - page 314

public void printResult( double result) {
System.out.println("The result is: " + result);
}

}
This listing declares a class that implements the interface in listing 16.1. The details of
the implementation aren't relevant to OSG i, so we'll skip it.
There's no big difference between testing OSG i services and POJO s. You can reuse
the test from chapter 1 and include it in a build, as we show in part 3 of this topic. This
chapter doesn't cover unit testing alone; it covers integration testing of OSG i services.
Before we continue discussing the integration testing of the service that we just imple-
mented, we create a bundle to hold our service and install the service with Apache
Felix, an open source implementation of the OSG i R4 Service Platform.
To create the bundle we need an implementation of the BundleActivator inter-
face to register and unregister the service, as shown in listing 16.3.

Listing 16.3 CalculatorBundleActivator

[...]
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

B

C
D
E

public class CalculatorBundleActivator implements BundleActivator {

public void start(BundleContext bundleContext) throws Exception {
System.out.println("Starting calculator service ...");
bundleContext.registerService(
CalculatorService. class .getName(), new CalculatorImpl(), null );
}

F

public void stop(BundleContext bundleContext) throws Exception {
System.out.println(“Stopping calculator service ...”);

}
}
We start by importing the required classes B from felix.jar in the FELIX_HOME bin/
directory. Next, we declare our class to implement the BundleActivator interface C .
In D and F , we implement the required start and stop methods, which define how
the bundle will behave once it's started or stopped. In the start method, we register
the CalculatorService interface with the given BundleContext E . By doing so we
notify the framework of our service, and our next step is to expose the interface to
other services.
Our stop method F doesn't need to do anything because Felix automatically
unregisters the service when it stops.
To expose our calculator service so that it can be used by other services, we need to
include it in a bundle: a JAR file containing all of our classes and the MANIFEST . MF file
shown in listing 16.4.