2 Understanding the Messaging Bridge

The following sections describe WebLogic Messaging Bridge concepts and functionality:

• What Is a Messaging Bridge?

• Messaging Bridge Components

• Configuring and Managing a Messaging Bridge

What Is a Messaging Bridge?

The WebLogic Messaging Bridge is a forwarding mechanism that provides interoperability between WebLogic JMS implementations, and between JMS and other messaging products. Use the Messaging Bridge to integrate your messaging applications between:

• Any two implementations of WebLogic JMS, including those from separate releases of WebLogic Server.

• WebLogic JMS implementations that reside in separate WebLogic domains.

• WebLogic JMS and a third-party JMS product (for example, MQSeries).

A messaging bridge instance forwards messages between a pair of bridge source and target destinations. These destinations are mapped to a pair of bridge source and target destinations. The messaging bridge reads messages from the source bridge destination and forwards those messages to the target bridge destination. For WebLogic JMS and third-party JMS products, a messaging bridge communicates with source and target destinations using the Java EE Connector Architecture (JCA) resource adapters provided with WebLogic Server. See Figure 2-1.

Figure 2-1 WebLogic Messaging Bridge

Description of "Figure 2-1 WebLogic Messaging Bridge"

You designate source and target bridge destinations as either "queues", "topics", or "distributed destinations", as described in Programming JMS for Oracle WebLogic Server. Optionally, specify a quality of service (QOS), including message filters, transaction semantics, and connection retry policies. Once you configure a messaging bridge you can perform management tasks easily from the Administration Console, including suspending bridge traffic temporarily whenever necessary and monitoring the status of all your configured bridges.

Messaging Bridge Components

The following sections describe resources needed to use a messaging bridge:

• Resource Adapters

• Source and Target Bridge Destinations

• Messaging Bridge Instance

Resource Adapters

A messaging bridge uses JCA resource adapters to communicate with the configured source and target JMS destinations. Associate both the source and target JMS destinations with a supported resource adapter in order for the bridge to communicate with them. The JNDI name for the adapter is configured as part of the resource adapter's deployment descriptor. See Table 2-1.

Resource adapters for different types of JMS destinations are provided in exploded format or in a .rar file. The exploded format gives you an easy way to modify resource adapter deployment descriptor parameters, such as the max-capacity of the connection factory that specifies the maximum number of connections available for bridge instances.

Note:

Changing a deployment descriptor for a resource adapter using the exploded format does not update the descriptor packaged in the .rar file. See Setting the Number of Connection Factories.

The supported resource adapters are located in the WL_HOME\server\lib directory and are described in Table 2-1.

Table 2-1 Messaging Bridge Resource Adapters and JNDI Names

Adapter	JNDI Name	Description
jms-xa-adp	eis.jms.WLSConnectionFactoryJNDIXA	Provides transaction semantics the XAResource. Used when the required QOS is Exactly-once. This envelops a received message and sends it within a user transaction (XA/JTA). The following requirements apply to use of this resource adapter: Any WebLogic Server implementation being bridged must be release 7.0 or later. The source and target JMS connection factories must be configured to use the XAConnectionFactory. Note: Before deploying this adapter, refer to the Configuring Interoperability for WebLogic Domains for specific transactional configuration requirements and guidelines.
jms-notran-adp	eis.jms.WLSConnectionFactoryJNDINoTX	Provides no transaction semantics. Used when the required QOS is Atmost-once or Duplicate-okay. If the requested QOS is Atmost-once, the resource adapter uses AUTO_ACKNOWLEDGE mode. If the requested QOS is Duplicate-okay, CLIENT_ACKNOWLEDGE is used. Note: For more information about the acknowledge modes used in non-transacted sessions, see "Understanding WebLogic JMS" in Programming JMS for Oracle WebLogic Server.

Source and Target Bridge Destinations

A messaging bridge connects two actual destinations that are mapped to bridge destinations: a source destination from which messages are received, and a target destination to which messages are sent.

JMS Bridge Destinations

For JMS messaging products, whether it is a WebLogic JMS implementation or a third-party JMS provider, configure a JMS bridge destination instance for each actual source and target JMS destination being mapped to a messaging bridge. A JMS bridge destination instance defines a unique name for a bridge's source and target destinations within a WebLogic domain; the name of the adapter used to communicate with the specified destination; property information to pass to the adapter (such as Connection URL and Connection Factory JNDI Name), and, optionally, a user name and password. See "Create JMS bridge destinations" in Oracle WebLogic Server Administration Console Help. See:

• Interoperating with Different WebLogic Server Releases or Interoperating with Foreign Providers sections for specific configuration requirements and guidelines.

• When configuring third-party JMS provider bridge destination, use the Foreign JMS Server feature to configure multiple source or target destinations quickly. See "Configuring Foreign Server Resources to Access Third-Party JMS Providers" in Configuring and Managing JMS for Oracle WebLogic Server.

Messaging Bridge Instance

A messaging bridge instance communicates with the configured source and target bridge destinations. For each mapping of a source destination to a target destination, whether it is another WebLogic JMS implementation or a third-party JMS provider, you must configure a messaging bridge instance. Each messaging bridge instance defines the source and target destination for the mapping, a message filtering selector, a QOS, transaction semantics, and various reconnection parameters. See "Create Messaging Bridge Instances" in Oracle WebLogic Server Administration Console Help.

Configuring and Managing a Messaging Bridge

The following sections provide information on how to use the Administration Console to configure and manage a messaging bridge:

• Create a Messaging Bridge Instance

• Manage a Messaging Bridge Instance

Create a Messaging Bridge Instance

Creating a messaging bridge consists of the following tasks:

1. Create source and target bridge destinations.

2. Deploy a resource adapter.

3. Create a messaging bridge instance.

4. Target the messaging bridge.

The Administration Console assists you in creating a messaging bridge by deploying an appropriate resource adapter and setting the values of some attributes. Consider changing messaging bridge settings to better suit your environment. See "Create Messaging Bridge Instances" in Oracle WebLogic Server Administration Console Help.

Manage a Messaging Bridge Instance

Typical tasks required to manage a messaging bridge using the Administration Console include:

• Monitoring the status of all configured messaging bridges in your domain. See "Monitor messaging bridge instances" in the Oracle WebLogic Server Administration Console Help.

• Suspending and restarting an active messaging bridge. See "Suspend and restart messaging bridges" in the Oracle WebLogic Server Administration Console Help.

• Configuring the default execute thread pool size for your messaging bridges. See "Configure messaging bridge execute thread pool size" in the Oracle WebLogic Server Administration Console Help.

• Deploying a resource adapter. See "Deploy resource adapters" in the Oracle WebLogic Server Administration Console Help.

• Creating a trusted security relationship. See "Configuring Domains for Inter-Domain Transactions" in Programming JTA for Oracle WebLogic Server.