Messaging Bridge

 

A messaging bridge is responsible for transferring messages between two JMS providers. The WebLogic Messaging Bridge feature allows you to configure a store and forward mechanism between any two JMS providers—including separate implementations of WebLogic JMS.

Specifically, you can configure a source/target mapping of a JMS destination (queue or topic) to another JMS destination, and vice versa. Messages that are sent to the source destination are then automatically forwarded to the target destination. The messaging bridge also allows the configuration of quality of service (QOS), message filtering, transaction semantics, and reconnection policies.

For each source/target JMS destination to be mapped, whether it is a WebLogic JMS destination or a 3rd-party JMS provider, you must configure a JMS Bridge Destination instance. If the source/target destination is for a non-JMS messaging product, you must configure a General Bridge Destination instance.

 

---

Creating a Messaging Bridge

To configure a messaging bridge, follow these steps:

1. Click to expand the Messaging Bridge node.

2. Click the Bridges node to open the Bridges tab in the right pane.

3. Click the Configure a new Messaging Bridge link in the right pane. A Configuration dialog displays in the right pane showing the tabs associated with configuring a new messaging bridge.

4. On the Configuration General tab, enter values in the Name, Source Destination, Target Destination, Selector, Quality of Service, QOS Degradation Allowed, Maximum Idle Time, Asynchronous Mode Enable, Durability Enabled, and Started attribute fields. For more information about messaging bridge general attributes, see General.

5. Click Create to create an instance of the messaging bridge with the name you specified in the Name field. The new instance is added under the Bridges node in the left pane.

6. Click the Connection Retry tab and change the attribute fields or accept the default values as assigned. For connection retry attribute descriptions, see Connection Retry. Click Apply to save your changes.

7. Click the Transactions tab and change the attribute fields or accept the default values as assigned. For transaction attribute descriptions, see Transactions. Click Apply to save your changes.

8. Click the Targets tab and assign the messaging bridge to servers, clusters, or a migratable target server. See Assigning a Messaging Bridge to One or More Servers, or Clusters, or a Migratable Target for instructions. Click Apply to save your changes.

9. Click Apply to save your changes.

 

---

Cloning a Messaging Bridge

1. Click to expand the Bridges node. The Messaging Bridges table displays in the right pane showing all the Messaging Bridge instances.

2. Click the Clone icon in the row of the messaging bridge you want to clone. A dialog displays in the right pane showing the tabs associated with cloning a messaging bridge.

3. Enter values in the attribute fields.

4. Click Clone to create a messaging bridge with the name you specified in the Name field. The messaging bridge is added to the Messaging Bridges table in the right pane.

 

---

Deleting a Messaging Bridge

1. Click to expand the Messaging Bridge node. The Messaging Bridges table displays in the right pane showing all the messaging bridge instances.

2. Click the Delete icon in the row of the messaging bridge that you want to delete. A dialog displays in the right pane prompting you to confirm your deletion request.

3. Click Yes to delete the messaging bridge, and then click Continue to redisplay the Messaging Bridges table in the right pane. The messaging bridge is deleted from the Messaging Bridges table.

 

---

Assigning a Messaging Bridge to One or More Servers, or Clusters, or a Migratable Target

1. In the left pane, click the Bridges node to expand it.

2. Click the Messaging Bridge node to expand it and show the list of messaging bridges defined in your domain.

3. Click the messaging bridge that you want to assign. A dialog displays in the right pane showing the tabs associated with the messaging bridge instance.

4. Click the Targets tab to display the following targeting tabs.

   • Servers—you can select a server or servers where the messaging bridge will be deployed. The messaging bridge will be available on all the selected servers.

   • Clusters—you can select a cluster where the messaging bridge will be deployed. The messaging bridge will be available on all servers in the selected cluster.

   • Migratable Targets—you can select a WebLogic Server migratable target where the messaging bridge will be deployed. When WebLogic Server is first booted, the messaging bridge is initially available only on the user-preferred server. After that, the bridge can be migrated to another server listed in the migratable target

5. On the Servers, Clusters, or Migratable Targets tabs, assign the messaging bridge, as follows:

   1. In the Available column, select one or more targets to assign to the messaging bridge.

   2. Move the targets into the Chosen column by clicking the mover control.

   3. Click Apply to save your assignments.

 

---

Adding a Note to a Messaging Bridge

1. In the left pane, click the Bridges node to expand it.

2. Click the Messaging Bridge node to expand it and show the list of messaging bridges defined in your domain.

3. Click the messaging bridge that you want to add a note to. A dialog displays in the right pane showing the tabs associated with the messaging bridge instance.

4. Click the Notes tab. Type a note in the Notes field.

5. Click Apply to save your changes.

 

---

Stopping and Restarting a Messaging Bridge

To temporarily suspend a messaging bridge, follow these steps:

1. Click to expand the Messaging Bridge node.

2. Select the messaging bridge instance that you want to stop.

3. On the Configuration General tab, clear the Start check box to stop the bridge.

4. To restart the bridge, select the Start check box.

 

---

Monitoring All Active Messaging Bridges

1. Click the server node in the left pane.

2. Select a specific server in the left pane. A dialog displays in the right pane showing the tabs associated with the server instance

3. Select the Services tab.

4. Select the Bridge tab.

5. Click the Monitor all Messaging Bridge Runtimes text link. A table displays showing all active messaging bridges for the server.

 

---

Configuring the Execute Thread Pool Size

You can configure the default execute thread pool size for your messaging bridges. For example, you may want to increase or decrease the default size to reduce competition from the WebLogic Server default thread pool. Entering a value of -1 disables this thread pool and forces the bridge to use the WebLogic Server default thread pool.

1. Click the Servers node in the left pane to expand it.

2. Select a specific server instance.

3. Select the Services tab in the right pane.

4. Select the Bridge tab.

5. Enter a new value in the Messaging Bridge Thread Pool Size field.

6. Click Apply to save your changes.

 

---

Configuration

General

Attribute	Description	Range of Values	Default Value
Name	A messaging bridge name that is unique across the WebLogic Server domain. This attribute is not dynamically configurable.	Java identifier, unique within specific domain.	MyMessaging Bridge [-n]
Source Destination	The source destination from which messages are received by the messaging bridge. This attribute is not dynamically configurable.	Existing source bridge destination name.	Null
Target Destination	The target destination to which messages are sent from the messaging bridge. This attribute is not dynamically configurable.	Existing target bridge destination name.	Null
Selector	Allows you to filter the messages that are sent across the messaging bridge. Only messages that match the selection criteria are sent across the messaging bridge. For queues, messages that do not match the selection criteria are left behind and accumulate in the queue. For topics, messages that do not match the connection criteria are dropped. Note: For more information on using selectors to filter messages, see "Developing a WebLogic JMS Application" in Programming WebLogic JMS. This attribute is not dynamically configurable.	The value must be an alphanumeric string.	None
Quality of Service	Defines the guarantees for forwarding a message across a messaging bridge. The valid qualities of service are: Exactly-once—Each message will be sent exactly once. This is the highest quality of service. Atmost-once—Each message is sent at most one time. Some messages may not be delivered to the target destination. Duplicate-okay—Each message is sent at least one time. Duplicate messages can be delivered to the target destination. Note: In order to use Exactly-once, the source and target connection factories must be configured to use XAConnectionFactory. Also, the jms-xa-adp.rar adapter must be deployed and identified in the Adapter JNDI Name attribute for the source and target destinations. This attribute is not dynamically configurable.	Exactly-once, Atmost-once, and Duplicate-okay	Exactly-once
QOS Degradation Allowed	When selected, the messaging bridge will automatically degrade the requested QOS (quality of service) when the configured one is not available. If this occurs, a message is delivered to the WebLogic startup window (or log file). If this option is not selected (false), and the messaging bridge cannot satisfy the requested QOS, it will result in an error and the messaging bridge will not start. This attribute is not dynamically configurable.	Boolean Enabled = selected Disabled = not selected	Not selected
Maximum Idle Time (seconds)	For bridges running in a asynchronous mode, this is the maximum amount of time, in seconds, the messaging bridge will sit idle before checking the health of its connections. For bridges running in a synchronous mode, this dictates the amount of time the messaging bridge can block on a receive call if no transaction is involved.	0 through 231 - 1	60
Asynchronous Mode Enabled	Defines whether a messaging bridge works in asynchronous mode. Messaging bridges that work in asynchronous mode (true) are driven by the source target. The messaging bridge listens for messages and forwards them as they arrive. When the value is false, the bridge is forced to work in synchronous mode, even if the source supports asynchronous receiving. Note: For a messaging bridge with a QOS of Exactly-once to work in asynchronous mode, the source destination has to support the MDBTransaction interface described in the weblogic.jms.extensions Javadoc. Otherwise, the bridge will automatically switch to synchronous mode if it detects that MDBTransactions are not supported by the source destination. For more information about MDBTransactions, see "Using Message-Driven Beans" in Programming WebLogic EJB. This attribute is not dynamically configurable.	Boolean Enabled = selected Disabled = not selected	Selected
Durability Enabled	A messaging bridge that has this attribute set to true creates a durable subscription for the source destination—providing the source destination type is a topic. This allows the source JMS implementation to save messages that are sent to it when the bridge is not running. The bridge will then forward these messages to the target destination once it is restarted. If the value is set to false, messages that are sent to the source JMS topic while the bridge is down cannot be forwarded to the target destination. Note: This attribute is used only for JMS topics or when a destination has similar characteristics. Note: If a bridge must be taken permanently offline, you must delete any durable subscriptions that use the bridge. For information on deleting durable subscribers, see "Deleting Durable Subscriptions" in Programming WebLogic JMS. This attribute is not dynamically configurable.	Boolean Enabled = selected Disabled = not selected	Not selected
Started	Defines the initial state of the messaging bridge at run-time (that is, the state when it boots). The default value is on (true). By clearing this check box (false), you can stop the messaging bridge. Conversely, reselecting the check box, restarts the bridge. Note: This does not indicate the run-time state of the bridge. For information on monitoring a bridge's state, see Monitoring All Active Messaging Bridges	Boolean Enabled = selected Disabled = not selected	Selected

Connection Retry

Attribute	Description	Range of Values	Default Value
Minimum Delay (seconds)	The minimum delay, in seconds, between reconnection attempts. When a messaging bridge boots and cannot connect to a destination, or a connection is lost and the messaging bridge is first attempting to reconnect, it will attempt to reconnect in this specified amount of seconds. This attribute is not dynamically configurable.	0 through 231 - 1	15
Incremental Delay (seconds)	The delay increment, in seconds, between reconnection attempts. Each time a bridge fails to reconnect, it will add this amount of seconds to the delay before it makes its next reconnection attempt. This attribute is dynamically configurable.	0 through 231 - 1	5
Maximum Delay (seconds)	The maximum delay, in seconds, between reconnection attempts. Each reconnection attempt is delayed further by the Incremental Delay amount of seconds, but it is never delayed by more than this value. This attribute is dynamically configurable.	0 through 231 - 1	60

Transactions

Attribute	Description	Range of Values	Default Value
Transaction Timeout	Defines the number of seconds the transaction manager will wait for each transaction before timing it out. Transaction timeouts are used when a bridge's quality of service requires transactions. This attribute is not dynamically configurable.	0 through 231 - 1	30
Batch Size	Defines the number of messages that the messaging bridge transfers within one transaction. This attribute only applies to bridges that work in synchronous mode and whose quality of service require two-phase transactions. This attribute is dynamically configurable.	0 through 231 - 1	10
Batch Interval (milliseconds)	Defines the maximum time, in milliseconds, that the bridge will wait before sending a batch of messages in one transaction, regardless of whether the Batch Size amount has been reached or not. This attribute only applies to bridges that work in synchronous mode and whose quality of service require two-phase transactions. This attribute is dynamically configurable.	0 through 231 - 1	-1

 

---

Targets

Attribute	Description	Range of Values	Default Value
Migratable Targets	Defines a WebLogic Server migratable target where the messaging bridge will be deployed. When WebLogic Server is first booted, the messaging bridge will initially be available only on the user-preferred server. Afterwards, the bridge can be migrated to another server in the migratable target using either the Administration Console or the command-line tool.	List of available and chosen targets.	No targets are chosen.
Clusters	Defines a WebLogic Server cluster where the messaging bridge will be deployed. The messaging bridge will be available on all servers in the selected cluster.	List of available and chosen targets.	No targets are chosen.
Servers	Defines the WebLogic Servers where the messaging bridge will be deployed. The messaging bridge will be available on all the selected WebLogic Servers.	List of available and chosen targets	No targets are chosen.

 

---

Notes

Attribute	Description	Range of Values	Default Value
Notes	This attribute provides a space for user-supplied information.	The value must be an alphanumeric string.	Null