Weblogic JMS (Java Message Service)

 

At the end of this chapter you will be able to:

• Understand how WebLogic Server JMS is implemented
• Configure JMS administered objects using the administration console
• Configure persistent messages
• Use the WLS administration console to monitor JMS

Message-Oriented Middleware

• Message-oriented middleware refers to an infrastructure that supports messaging.
• Typical message-oriented middleware architectures define these elements:
  • Message structure
  • The way to send and receive messages
  • Scaling guidelines

Point-to-Point (PTP) Queue

• Many producers can serialize messages to multiple receivers in a queue.

 

Publish-Subscribe Topics

• Publishing and subscribing to a topic decouple producers from consumers.

 

WebLogic Server JMS Features

• WebLogic Server JMS supports:
  • PTP and Pub/subdomains
  • Guaranteed and transactional message delivery
  • Durable subscribers
  • Distributed destinations
  • Recovery from failed servers

  JMS Architecture: Connecting

 

JMS Architecture: Sending Messages

 

Transacted Messaging

• A JMS client can use JTA to participate in a distributed transaction.
• Alternatively, a JMS client can demarcate transactions local to the JMS Session, through a transacted session.
• Participation in a transaction is optional.

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Administrative Tasks

• Administrative tasks include these:
  • Creating and monitoring JMS Servers
  • Creating connection factories
  • Creating and monitoring destinations
  • Creating JMS stores
  • Configuring thresholds and quotas
  • Configuring durable subscriptions
  • Managing JMS service fail-over

WLS JMS Server

• In WLS, the messaging service is implemented through a JMS Server.
• A JMS Server receives and distributes messages.

 

Create a JMS Server

   

Target a JMS Server

 

Configure a JMS Server

 

JMS Resources

• JMS resources are managed as system modules, application modules, or packaged JDBC resource modules.

 

Modular JMS Resource Configuration and Deployment...

• JMS configurations in WebLogic Server are stored as modules
  • Defined by an XML file that conforms to the Weblogic-jmsmd.xsd schema
  • Similar to standard J2EE modules
• An administrator can create and manage JMS modules as:
  • Global system resources
  • Global standalone modules
  • Modules packaged with an enterprise application
• An advantage of modular deployment is simplified migration between environments, such as:
  • From development to integration
  • From system test to production
• You can migrate your application and the required JMS configuration:
  • Without opening an EAR file
  • Without extensive manual JMS reconfiguration

Connection Factory

• A connection factory:
  • Encapsulates connection configuration information
  • Is used to create pre-configured connections
  • Is stored in JNDI
  • Can be targeted to servers or clusters
• WLS provides a default connection factory that is bound in JNDI to weblogic.jms.ConnectionFactory.
• When a new configuration is required, a new connection factory can be created.

 

Configure Connection Factory: Default Delivery

   

Configure Connection Factory: Client

 

Configure Connection Factory: Transactions

 

Configure Connection Factory:  Flow Control

 

Destination

• A destination is a lightweight object stored in JNDI.
• It is the target on a JMS Server for sending or receiving messages.
• The JMS destination types are:
  • Queue
  • Topic

Create a Queue Destination…

 

Threshold and Quota

• A threshold and a quota can be set for Server and Destination objects.
• A quota is a limit defined for JMS administered objects; it includes these values:
  • The maximum number of bytes that can be stored
  • The maximum number of messages that can be stored
• A threshold is a limit that triggers message paging, flow control, and logged warnings, using:
  • Upper and lower values for the number of bytes
  • Upper and lower values for the number of messages

Configuring Thresholds and Quotas

Configuring Persistent Messaging  

Durable Subscribers and Subscriptions

• Durable subscribers register durable subscriptions to guarantee message delivery even if subscribers are inactive.
• A subscriber is considered active if the Java object that represents it exists.
• By default, subscribers are non-durable.
• Administrators configure:
  • Where messages are persisted
  • Persistent connection factories and destinations

When to Use Persistent Messaging

• Persistent messaging permits messages in memory to be written out to a persistent store.
• Configure persistent messaging if:
  • Development requires durable subscriptions (use durable subscribers in the application)
  • You require that in-progress messages persist across server restarts

How a Durable Subscription Works

• If a subscriber client is active, messages are delivered normally:
• When the client becomes active again, its ID is used to retrieve and redeliver messages.

   

Configure a Durable Subscription

• To configure durable subscriptions, an administrator must:
  • Create and configure a JMS store
  • Configure connection factories or destinations as persistent
  • Associate the JMS store with the JMS Server
• The JMS store can be configured to use either:
  • A file store
  • A JDBC store (a connection pool)

Create a JMS File Store…

   

Create a JMS JDBC Store…

• To configure JMS JDBC persistence:
  • Create a JDBC DataSource.
  • Create a JMS store and refer to the JDBC DataSource.
  • Refer to the JMS store from the JMS Server configuration.
• The required infrastructure (tables, and so on) is created automatically.

   

Assign a Store to a JMS Server

 

Persistent Connection Factory

 

 

Monitoring JMS in WLS Statistics for JMS Objects

• Statistics are provided for the following JMS objects:
  • JMS servers
  • Connections
  • Destinations

Monitor JMS Servers…

 

Monitor Destinations

 

Summary:

In this chapter, we learned how to:

• Understand messaging concepts
• Understand WebLogic Server’s JMS support
• Configure JMS servers, queues, and topics
• Monitor JMS servers, queues, and topics

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