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Figure 13.9 If you install the fancyfoods.department.chocolate bundle before the
fancyfoods.api bundle, the chocolate bundle can't be resolved. Exploring the snapshotted OSGi state
shows the reason for the resolution failure.
Although Virgo is a well-established alternative to Apache Aries, there are several
other independent enterprise OSG i implementations. Since version 3, GlassFish ships
with enterprise OSG i support. The support available in version 3 was mostly limited to
web applications, but much more complete support, including JPA , JTA , and EJB inte-
gration, shipped in version 3.1. GlassFish has coined the term hybrid applications to
describe applications that combine the modularity of OSG i with the ability to take
advantage of Java EE infrastructure. The hybrid application programming model is
the enterprise OSG i programming model, but we think the phrase nicely captures the
ideas behind enterprise OSG i.
Dependency injection
Uniquely among the servers in this chapter, GlassFish doesn't include a Blueprint
implementation. The assumption is that users will use Java EE 's CDI (Contexts and
Dependency Injection) for inversion of control. In its base form, CDI has no aware-
ness of OSGi, but GlassFish has extended it with an @OSGiService annotation that
allows services to be injected. This approach has the advantage of being annotation-
based, which allows dependencies to be injected concisely. It will also feel natural if
you're already used to using CDI . But because it's not standards-based, applications
written for the GlassFish CDI won't be portable to other application servers.
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