BPEL4WS1.1学习笔记[1]

本文是我两个月前初读bpel规范时总结出来的一点咚咚。hoho~当时写在实习日志上，东一榔头西一棒槌的可能很没有条理~欢迎大家批评指正。

预备知识：

1.Partner Link Type：用来表示服务间的依赖关系（dependencies）

每个Partner link type定义至多2个“role”names，lists the portTypes that each role must support for the interaction to be carried out.

2.partner link types: purchasingLT & schedulingLT

前者表示connection between the process & the requesting customer the purchase order service needs to offers a service operation ("sendPurchaseOrder").后者表示了interaction between the purchase order service & the schedulingservice.只有scheduling service 的operations被invoked.

3.invoicingLT & shippingLT定义2个roles

both the user of the invoice calculation & the user of the shipping service must provide callback operations to enable asynchronous notifications to be asynchronously sent.

4.invoiceCallbackPT & shippingCallbackPT portTypes

5.默认命名空间xmlns：

别名，正在使用多个命名空间时，别名根据需要用作元素或属性的前缀。

三个必须声明的外部命名空间是WSDL,SOAP,XMLSchema.

xmlns="http://schema.xmlsoap.org/wsdl/"是WSDL默认命名空间。

xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"是SOAP命名空间。

xmlns:xsd="http://www.w3.org/2001/XMLSchema"是XMLSchema命名空间。

WSDL1.1，XMLSchema1.0，XPath1.0，WS-Addressing

TargetNameSpace:is a convention of XML Schema that enables the WSDL document to refer to itself.

6.purchase order process 作为invoice,shipping服务的user,必须提供回调操作以供call back.

7.几个processes：

1. purchase order process
2. invoice service
3. shipping service
4. production scheduling process

<variables>:

1. WSDL Message types
2. XMLSchema simple types
3. XMLSchema elements

<partnerLinks>partnerLinkType & role name表示出了purchase order business process and other partner need to implement 需要实现portTypes

<faultHandlers>faults are identified by a qualified name(QName)

<sequence>

<receive>

<flow>

<reply>

</sequence>

3个并发活动之间的同步依赖关系用“links”连接。

link：connect a source activity to a target activity.

没有link时，<flow>中的活动并发执行，link引进了control dependency（控制依赖）

---

query Language：XPath1.0

expression Language: XPath1.0

suppressJoinFailure:流程中所有活动的JoinFailure故障是否被抑制。默认是“no”。

enableInstanceCompensation：流程实例作为一个整体可被平台特定的方法补偿。默认“no”

abstractProcess：流程是否被定义为abstract.默认“no”

<terminate>只能用在executable processes

<receive>允许流程阻塞等待一个匹配消息的到达

<reply>允许流程send a message in reply to a message that was received through a <receive>

<invoke>允许流程调用一个单向(one-way) or request-response operation on a portType offered by a partner

<assign>更新variables的值，一个<assign>可包含任意数量的基本数值

<throw>生成故障from inside the business process

<wait>wait for a given time period or until a certain time has passed.Exactly one of the expiration criteria must be specified

<empty>insert a "no-operation" instruction into a business process .useful for 同步并发活动

<sequence>define a collection of activities to be performed sequentially in lexical order

<switch>select exactly one branch of activity from a set of choices

<while>repeat an activity until a certain criteria has been met

<pick>block and wait for a suitable message to arrive or for a time-out alarm to go off .When one of these triggers occurs,the associated activity is performed and the pick completes

<flow>指定一个或多个并行的活动，并行活动之间可以定义links从而定义任意的control structures

<scope>定义嵌套的活动及其相关的variables,fault handlers,compensation handlers

<compensate>只能在正常完成的内层作用域（inner scope）调用compensation.can only be invoked from within a fault handler or another compensation handler

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流程实例的创建是隐式的，接收消息的活动(receive & pick)可加上注解，以表示活动的进行将导致业务流程的新实例被创建。注解的方式是把这种活动的属性createInstance设置为“Yes”。当消息被这样的活动接收到后，如果该业务流程的实例还不存在，那么该业务流程的实例将被创建。这种活动是“start activity”

要使不止一个启动活动被并发地执行，所有这些活动必须使用至少一个correlation set 并必须使用同一个correlation set