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Chapter 5. Common Messaging Terms

Definitions

Java Message Service, JMS
A Java API implementing a messaging standard that allows application components based on J2EE to create, send, receive, and read messages. It enables distributed communication that is loosely coupled, reliable, and asynchronous.
client
An application that uses the message broker to communicate with other applications. These applications use one of the broker's client API to connect to and interact with the broker.
consumer
An application that consumes messages from a messaging destination.
connection factory
An object that a client uses to create a connection to a broker. A factory supports attributes that configure the quality of service for the connections it creates.
destination
A logical holding area for messages in a message broker. Clients publish messages to and consume messages from destinations.
See also: queue, topic
durable subscriber
A message consumer that receives all messages published on a topic, including those published while the subscriber is inactive.
message
An atomic unit of data that is passed between two or more clients. A message consists of three components:
  • headers—contain a predefined set of metadata that is used to communicate information about a message between the different parties that handle the message
  • properties—contain application defined metadata about a message to the different parties that handle the message
  • body—contains the messages payload
message selector
A string containing a boolean SQL statement using SQL 92 syntax that is used to select messages based on JMS message header properties.
message group
A collection of JMS messages that are assigned the same JMSXGroupID.
When used in conjunction with the JMSXGroupSeq message groups can be used to ensure that messages are processed in the proper sequence.
master/slave
A topology in which a single instance, the master, is active and one or more instances, the slaves, are ready to resume when the active instance stops.
producer
An application that creates messages and posts them to a messaging destination.
point-to-point messaging
A messaging style where messages are sent between two known endpoints. This messaging style is typically implemented using queues.
publish and subscribe messaging, pub/sub
A messaging style where message producers send(publish) messages to a destination and interested consumers can register(subscribe) to receive messages from the destination. This style of messaging is implemented using topics.
queue
A destination that uses first in/first out semantics.
See also: destination
request-reply pattern
A messaging pattern in which a message producer receives a message and returns a correlated message.
Session
A JMS object that provides a single-threaded context for producing and consuming messages. JMS clients use the Session object to create producers, consumers, messages, and other artifacts used to work with messages.
Streaming Text Orientated Messaging Protocol, STOMP
A language agnostic, simple text-based protocol that allows clients to talk with any message broker supporting the protocol.
transport
A standards-based network protocol, such as HTTP or STOMP, that defines how objects communicate over a network.
topic
A destination that uses publish and subscribe semantics.
See also: destination