The JMS server acts as a hub in a hub-and-spoke network, receiving and distributing messages. Applications that send and receive messages are clients that connect to the JMS server via TCP. JMS offers two messaging types: point-to-point queues that send messages to a specific application, and publish-subscribe topics that broadcast messages to multiple subscribers. Durable subscriptions allow applications to receive topic messages even when disconnected.
JMS Server Basics: Queues, Topics, and Durable Subscriptions
1. Main features of the JMS server Recapitulation of the basics of the JMS server
2. Main features of the JMS server Recapitulation of the basics of the JMS server The purpose of this section is to remind you of the main features of the Prodco JMS server.
3. Hub and spoke network A corporate integrated system is a number of separate applications like data bases, process engines etc.
4. Hub and spoke network Together these different applications work on the company’s business processes.
5. Hub and spoke network They co-ordinate their activities by exchanging messages.The Prodco JMS server is a means of exchanging messages.
6. The server is the hub Server The JMS server is at the centre of the network. The server receives and distributes messages.
7. Each client is a spoke Server Client Applications which send and receive messages are clients of the JMS server.
8. Each client is a spoke Server Client Clients connect to the JMS server using the TCP protocol.
9. Queues Queue When one or more applications send messages to one particular application, they put the messages on a queue.
10. A queue Audit and print purchase orders Manufacturing Servicing ACME.PURCHASEORDER.REQUEST Facilities EMS server This queue takes requests for purchase orders from all over the business to an application that prints purchase orders.
11. Topics Queue Topic The other sort of messaging uses a topic. A topic is like a broadcast: it conveys each message to several consumers.
12. Durable subscriptions Queue Topic If an application needs to receive messages that were sent on the topic while the application was disconnected…
13. Durable subscriptions Queue Topic …the application can create a durable subscription, and the server will hold messages for it while it is unavailable.
14. A topic Mail handling Website Call centre ACME.ORDER.NEW Production planning Credit check Inventory check EMS server In this example orders arrive from various sources and the topic carries the orders to various applications.
15. Review JMS is an API specification fromSun Micro Systems JMS messaging is a hub and spoke design The JMS server is at the hub Clients are the spokes JMS offers two types of message sending Point to point with queues Broadcast with topics