Nirvana Enterprise Manager - JNDI Integration

Introduction

Nirvana supports integration with JNDI by providing a custom JNDI provider. This provider is used by the Enterprise Manager within the JNDI panel available by each selecting any realm node from the namespace tree.

Nirvana's JNDI provider enables Nirvana JMS clients to locate references to JMS administered objects. The provider stores object references within a nirvana channel, and locates the references to the objects using a channel iterator.

The JNDI panel enables the creation of jms TopicConnectionFactory, QueueConnectionFactory references as well as references to Topics and Queues. If a realm is part of a cluster, then the Nirvana JNDI context channel will be created on all cluster realms. This ensures that any object references bound into the context are available across each realm.

Creating the context

When you select a realm node from the namespace tree, one of the tabs on the right hand side of the Enterprise Manager will be labelled 'JNDI'. Selecting this tab will display the default JNDI panel for a realm. At this point there will be nothing drawn within the JNDI NameSpace tree. The image below shows the default JNDI panel.

The JNDI panel at this point does not contain any JNDI context information. By default, the 2 text fields labelled 'JNDI Context Factory' and 'JNDI Provider URL' will already contain information. The JNDI context factory specifies the class to use to the JNDI context, which is set to 'com.pcbsys.nirvana.nSpace.NirvanaContextFactory', being the name of the Nirvana JNDI context factory. The JNDI provider URL is the RNAME that each jndi connection reference will be created using. For a realm that is part of a cluster, the JNDI Provider URL will be a comma separated list of the rname values for each realm that is a member of the cluster. This ensures that not only will the JNDI context be the same within all cluster realms, but each jms client that uses the Nirvana Context Factory will be able to use any of the realms specified in the Provider URL.

Clicking on the 'Apply' button, will create the clustered nirvana context channel used to store all JNDI references. When this is created, each realm will then have a new channel called /naming/defaultContext . Also, the JNDI panel will also contain a new tree structure under the panel labelled 'NameSpace', the root of which will be the comma separated list of RNAME values. Double clicking on the root node in the JNDI namespace will render 4 tree nodes labelled 'Topic Connection Factories', 'Queue Connection Factories', 'Topics' and 'Queues'. The image below shows this view after the 'Apply' button has been clicked and the JNDI namespace tree has been double-clicked to expand it.

In order to allow jms clients to use the Nirvana Context Factory to reference objects via JNDI, we first of all need to create Topic and Queue connection factories. To do this, right click on the tree node labelled 'Topic Connection Factories' and select the menu option 'New Topic Connection Factory', which will display a dialog box allowing you to enter the name for the connection factory. Enter any name, in this example, we will use the name 'TopicConnectionFactory'. Click on 'OK' when you've entered the name, and you will see that a new node will have been created under the 'Topic Connection Factories' folder with the same name as you entered. The image below shows the JNDI namespace with a newly created topic connection factory.

As well as rendering the objects in the jndi namespace, an event is also published onto the '/naming/defaultContext' channel that corresponds to the newly entered connection factory. This event is what will be referenced by JMS clients when they attempt to find the details for the connection factory.

When JMS clients use the Nirvana JNDI context, they also reference the topics and queues from the same context. In order for these clients to access these objects we need to create references to each topic and queue. The topics (nirvana channels) and queues may already exist within the enterprise manager namespace, although they may not have been created within the JNDI context. Either way, by creating context references using the JNDI panel, jms clients will be able to access those objects.

In this example, we will add a new topic into the JNDI namespace that corresponds to a nirvana channel that already exists as a cluster channel. To do this, first, right-click on the folder called 'Topics' within the jndi namespace, and select the menu option 'New Topic'. If we enter the name /customer/sales, then a new object will be created under the 'Topics' folder called '/customer/sales'. This will also publish an event to the naming/defaultContext channel so that jms clients can look up the reference to this topic (channel) and begin using it within their application. The following image shows the newly created Topic within the JNDI namespace for the existing topic /customer/sales.

Once we have created both the topic connection factory and the topic, we can then see using the snoop panel, those references as they correspond to events on the naming/defaultContext channel. If you select the naming/defaultContext channel from the enterprise manager namespace and select the 'Snoop' panel. By selecting the 'Start' button from the snoop panel, you will be shown those JNDI entries that have been created. By selecting on any of the events you will then see the content of each event on the channel and the relevant JNDI context information relevant to the jms applications that will require it.

The image below shows and example of the Topic Connection Factory created earlier as it was created using the JNDI panel.