OSGi application design guidelines
When developing OSGi applications for WebSphere® Application Server, consider these design guidelines to make the most efficient use of OSGi technology.
The design guidelines described in this topic are:
Details for each of these guidelines are provided in the sections that follow.
Use OSGi services to configure EJB dependencies
If your OSGi application has a client bundle that references an EJB in a service bundle, use OSGi services to configure the EJB dependency.
To configure EJB dependencies by using OSGi services, complete the following steps:
- Here's why
- Configuring EJB dependencies by using OSGi services reduces the risk of the web or EJB container of the client bundle being recycled, or the client bundle itself being restarted, either of which might result in the temporary unavailability of one or more application endpoints.
Do not use the java:global or java:app namespaces
Do not use the java:global
or java:app
namespace references
to bind to EJBs unless necessary.
- Here's why
- These namespace references have the following fixed
formats:
java:global/application_name/module_name/ejb_name
However, the constituent parts of these references can change after an OSGi application is updated, so that the references must be modified accordingly, which makes this approach impractical. Furthermore, the exposure of the name of the underlying EJB in the reference, rather than using an abstraction such as an intermediate JNDI name, violates the principles of modular application design.java:app/module_name/ejb_name
Instead, use OSGi services to configure EJB dependencies, or declare an EJB reference and map it to the EJB JNDI name.
Note: If you definejava:global
orjava:app
references in an@EJB
annotation, or in a binding file, you receive a warning when you deploy the OSGi application as a business-level application.