Java Message Service (JMS)
Presenters:
 Nguyen Quoc Duy
 Dao Duy Khanh

Contents
1.
2.
3.
4.
5.
6.
7.

Messaging system & MOM
What is JMS?
Architecture of JMS
JMS Programming APIs
Steps for writing JMS Client
JBoss Messaging Service
Demo

1. Messaging system & MOM

Messaging system
 Allows two or more applications to exchange information in the form of message.
 When used in business systems – enterprise messaging systems or Message-Oriented
Middleware.
 Messages are delivered asynchronously from one system to others over a network.

Message Oriented Middleware (MOM)






Is infrastructure focused on sending and receiving messages.
Increase the interoperability, portability and flexibility of an application by allowing it to be distributed over heterogeneous platforms.
Support asynchronous calls.
Depend on message queue system, broadcast/multicast messaging systems.

MOM

2. What is JMS?

Java Message Service (JMS)






A specification that describes a common way for Java programs to create, send, receive and read distributed enterprise messages loosely coupled communication
Asynchronous messaging
Reliable delivery


A message is guaranteed to be delivered once and only once.
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JMS is an API

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JMS Design Goals


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Consistency with existing APIs
Independence from Messaging system provider Minimal effort on part of Messaging system provider Provide most of the functionality of common messaging systems

3. JMS Architectural
Components

JMS Architectural Components


JMS message




An object that contains the data being transferred between JMS clients.

Administered Objects



preconfigured JMS objects created by an admin for the use of clients
ConnectionFactory, Destination (queue or topic)

JMS Architectural Components
(Con’t)


JMS provider




JMS client




Is a messaging system – MOM – that implements
JMS interfaces and administrative functionality.
Java programs that sends/receives messages.

Non-JMS client


Use a message system native client API instead of JMS.

API

JMS Terminology


Domain (Messaging modes)


Point to point and publish/subscribe.

Session
 Connection.
 Destination
 Produce, send, publish
 Consume, receive, subscribe


JMS Domains
(Messaging Models)


JMS Point-to-Point




A message is consumed by a single consumer.

JMS Pub/Sub


A message is consumed by multiple consumers.

Point-to-Point
 A message is consumed by a single consumer  “Destination” of a message is a named queue.  FIFO (at the same priority level).
 Sender sends a message to the queue.
 Receiver extracts a message from the queue.  Message on a queue can be persistent or non-persistent Use it when every message you send must be processed successfully by one consumer

Publish/Subscribe (Pub/Sub)
 A message is consumed by multiple consumers.  “Destination” of a message is a named topic.
 Producers “publish” to topic
 Consumers “subscribe” to topic

When to use it?

 Use it when a message you send need to be processed by multiple consumers
 Example: HR application

JMS Messages

Messages
 The most part of the entire JMS specification.
 All data and events in a JMS application are communicated with messages.
 A Message object has three parts:

Message Header


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Used for message identification and routing.
Includes Destination.
Also includes other data:

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delivery mode (persistent, nonpersistent) message ID timestamp priority replyTo Message Header Fields

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JMSDestination
JMSDeliveryMode
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persistent or nonpersistent

JMSMessageID
JMSTimeStamp
JMSRedelivered
JMSExpiration

 JMSPriority
 JMSCorrelationID
 JMSReplyTo
 Destination supplied by a client; where to send or reply  JMSType
 Type of message body

Message Properties
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Provide the developer with more information about the message
Optional fields
Properties are Name/value pairs
Values can be byte, int, String, etc.

Message Body

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Holds content of message
Several types supported, each type defined by a message interface:

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Message
StreamMessage
MapMessage
TextMessage
ObjectMessage
BytesMessage

To create a simple ObjectMessage
ObjectMessage message = session.createObjectMessage(); message.setObject(myObject); queueSender.send(objectMessage);

NOTE: myObject must implement java.io.Serializable Message Selector


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Allows JMS consumers to select the message. Use message properties and headers as criteria in conditional expressions.
Use createReceiver, createSubsciber and createDurableSubscriber methods.

Message Selector Example
 An online retailer wants to deliver a special catalog to any customer that orders more then $500.00 worth of merchandise where the average price per item ordered is greater than $75.00 and the customer resides in one of several states.
String selector = "TotalCharge > 500.00 AND
((TotalCharge / ItemCount) >= 75.00) “ + "AND
State IN ('MN', 'WI', 'MI', 'OH')";
TopicSubscriber subscriber = session.createSubscriber(topic, selector,false);

Message Consumption


Synchronously
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A subscriber or a receiver explicitly finds the message from the destination by calling the receive method.
The receive method can block until a message arrives or can time out.

Asynchronously

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A client can register a message listener with a consumer. Whenever a message arrives at the destination, the JMS provider delivers the message by calling the listener's onMessage() method.

4. JMS Programming
APIs

Connection
Factory
creates
Connection
Message
Producer

creates

sends to
Destination

Session

creates

creates
Message

Message
Consumer
receives from Destination

Connection Factory



Is the object a client uses to create a connection with a provider.
Parent interface of QueueConnectionFactory and TopicConnectionFactory interfaces

Destination





Is the object a client uses to specific the target of messages it produces and the source of message it consumes.
It’s queue in PTP messaging domain and topic in Pub/Sub.
Parent interface of Queue and Topic interfaces. Connections




Once a connection factory is obtained, a connection to a JMS provider can be created.
Represents a communication link between the application and the messaging server.
Allows users to create sessions for sending and receiving messages from a queue or topic. Session




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Created from a Connection object
Once connected to the provider via a
Connection, all work occurs in the context of a Session
A session is single threaded.
Sessions also provide a transactional context

Message Producer



Created by a session.
Is used to send messages to a destination.

Message Consumer




Clients which want to receive messages create MessageConsumer object via Session object. Client can receive messages in two different modes: 


Blocking
Non-blocking

Receiving Message In
Blocking Mode



Client calls receive() method of
MessageConsumer object
Client blocks until a message is available

Receiving Message In
Non-blocking Mode

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Client registers a MessageListener object
Client does not block
When a message is available, JMS provider then calls onMessage() method of the
MessageListener object

Message Listener



Acts as an asynchronous event handler for messages. Contains onMessage() method that can define the action to be taken when a message arrives.

5. Steps for writing
JMS Client

6. What is JBM?

JBoss Messaging
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JBoss Messaging is the new enterprise messaging system from JBoss
Reliable, well featured, asynchronous open source messaging system
Fully compliant JMS 1.1 implementation
Fully JEE 5 compliant
Many features over and above JMS

JBoss Messaging Feature
• Fully JMS 1.1 and JEE5 compliant JMS implementation • Clustered queues and topics
– queues and topics are distributed across the cluster. You can send to a queue or a topic from any node, and receive from any other

• Message statistics
– gives you a rolling historical view of what messages were delivered to what queues and subscriptions • Very large queue support

JBoss Messaging Feature
• Intelligent message redistribution
• Transparent fail-over
– When a server fails, your sessions continue without exceptions on a new node as if nothing happened.

• Fully functional JMS message bridge
– enables you to bridge messages between any two JMS1.1 destinations on the same or physical separate locations.
(E.g. separated by a WAN). This allows you to connect geographically separate clusters, forming huge globally distributed logical queues and topics

JBoss Messaging Feature
• Delayed redelivery
• Limited redelivery attempts
• Expiry Queues
– An expiry queue is a special destination where messages are sent when they have expired

• Dead Letter Queues
– are system-generated queues used for storing messages that could not be delivered

JBoss Messaging Feature
•
•
•
•
•

Scheduled delivery
JMX interface
Pluggable JAAS security
Transports: TCP, SSL, HTTP
Support for most major databases : Oracle,
MySQL, PostgreSQL, Sybase ASE, MS SQL
Server
• Fully integrated with JBoss Transactions for full transaction recoverability.

JBoss Messaging Feature
• Message statistics
– gives you a rolling historical view of what messages were delivered to what queues and subscriptions • Very large queue support

The JBoss Messaging architecture

7. Demo

Thanks for your hearing.