Mule2.x Getting Started Guide笔记(一)Introduction

Mule2.x Getting Started Guide笔记(一)Introduction

1、what is mule
mule uses a service-oriented architecture(SOA) based on ideas from Enterprise Service Bus(ESB),enabling easy intergration of your existing systems.

2、Understanding the Messaging Framework
The heart of the system is the message bus,which routes messages between applications.Mule eliminates the need for a single message format(but the traditional ESB does).The information is sent on any communication channel,such as HTTP or JMS, and is translated only as needed along the way.

3、Understanding the mule Architecture
Services are discrete sets of functionality that are completely separate from each other but can work together.Because each service stands alone, services can be used as building blocks.

4.Separating Business Logic from Messaging
service components are completely shielded from the message format.Instead, a transport carries the message along, and transformers change the message's payload (such as the invoice) as needed to a format the service component can read before the router passes the message to the service component.Data is transformed only as needed. Instead of converting every message to a single common messaging format.

In summary, Mule provides a simple and lightweight way to write service components that do something to data without needing to worry about the sender or recipient of the data, the format of the data, or the technology being used to send/receive the data.

5.Understanding the logical Data Flow
Mule uses the Mule configuration file to determine which components, routers, transports, and transformers to use along the way.
The customer Invoice demo go like this:

step1: The customer places an order on the company web site, and an invoice is created as an XML form and submitted to http://myfirm.com/orders.

step2: The HTTP transport receives the XML invoice and wraps it in a Mule message. The Customer Data service's inbound endpoint is set to http://myfirm.com/orders, and its inbound router specifies that the message must contain a Java object, so the HTTP transport prepares to transform the XML invoice and dispatch the message to the service.

step3: The XML to Object transformer converts the XML invoice into a Java object.

step4: The transport passes the message with its transformed payload to the Customer Data service.

step5: The Customer Data service component queries the master customer database to pull additional data about the customer and updates the invoice with the data.

step6: The HTTP transport uses the outbound router configuration to determine that it must now dispatch the message to http://myfirm.com/verify.

step7: The HTTP transport uses the inbound router configuration of the Inventory Verification service to receive the message and pass it to the service component.

step8: The service component updates the invoice with an ID code of the warehouse that has all the items on the invoice in stock.

step9: The outbound endpoint specifies a JMS address, so the JMS transport dispatches the message to the order fulfillment application, which picks up orders on that address.

6.Integrating Mule into Your Environment
You can deploy each instance of Mule as a stand-alone application, in a web container (such as Apache Tomcat), or in an application server. You can use proprietary J2EE application servers such as BEA WebLogic, IBM WebSphere, Oracle Application Server, and SunOne, as well as in open source products like Geronimo or JBoss.