DeploymentManager Discovery:
As we discussed earlier the deployment manager plays an
important role in helping the deployer to deploy applications on
a J2EE product. A tool provider or a deployer cannot get a
reference to the deployment manager directly. For this purpose
the deployer uses a DeploymentFactory class to get the reference
of the deployment manager. The J2EE provider provides at least
one DeploymentFactory class which would return a reference to
the deployment manger present on the product.
The deployment API also defines a DeploymentFactoryManager class
which is a central repository of all Deployment factory
connections. The DeploymentFactoryManger has with it all the
Deployment Mangers that are registered for the product. When a
tool requests access for a Deployment Manager with a URI, it
checks in its existing pool of Deployment managers and returns
the appropriate Deployment Manager. If no manager is found it
returns a null.
Conclusion:
The J2EE deployment API is today in the nascent stages but a
right step in the direction of having the 'Write once run
anywhere' slogan of Java come true. It is a going to be a big
task for application servers in today's market to come to a
common table and provide a unified deployment process. Most of
today's market players leverage on providing simple and easy
tools like 'hot deployment of EJB', EAR verification etc to make
deployment easy for their customers. The Deployment API could
force these vendors to abandon some of these tools and adhere to
a mutually agreed standard. In some cases the differences are so
vast that vendors may have to do a lot of rework for a common
standard. Until then customers will have to live with the fact
that J2EE applications written in the same language, Java, may
not coexist on different servers.
Benoy Jose is a web developer with over six years of experience
in J2EE and Microsoft technologies. He is a Sun Certified
programmer and enjoys writing technical and non-technical
articles for various magazines.
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