Parsing XML elements in BPEL

Elements defined in WSDL
BPEL is a layer built on WebService. It also uses the description of WSDL in the definition of BPEL. However, it separates binding, service, and other parts of WSDL, this part of WSDL supports flexible binding configuration. In addition to the traditional WSDL (types, message, and porttype) types, the XML elements defined by BPEL are as follows:

<Partnerlinktype>In bpel2.0

<Partnerlinktype> S can be used to represent dependencies between services, regardless of whether a WS-BPEL business process is defined for one or more of those services. each <partnerlinktype> defines up to two "role" names, and lists the port types that each role must support for the interaction to be carried out successfully.

That is to say, <partnerlinktype> defines the dependencies between services. As mentioned in XML in WSDL, porttype can be understood as a service interface. Each porttype corresponds to a service,, the deployment of specific services has not yet started. Each <partnerlinktype> has two more <role> and each <role> corresponds to one and must correspond to one porttype. In my understanding, the role here is related to the business process, represents the execution process of an action. If only one party needs to define only one <role> during the interaction between the two parties, that is to say, a certain part of the business process, after receiving the request, you do not need to return the service result to the sender, but submit it to the next business process in sequence. In this process, only one rule is required between the initiator and the receiver, only the initiator rules are guaranteed. It is also easy to understand that at most two parties can only participate in one interaction.
The code in bpel2.0 is as follows <plnk: partnerlinktype name = "purchasinglt">

<Plnk: role name = "purchaseservice"

Porttype = "POS: purchaseorderpt"/>

</Plnk: partnerlinktype>

Note that<Partnerlinktype>It must be defined at the end of the WSDL.

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