This figure below presents the notion of exchange that is a main concept of SOA paradigm.
A exchange is composed of information to route exchange such as source address, destination endpoint and service name. It can also contains other metadata information to manage non-functional global contexts.
During the lifecycle of an exchange, it is composed of one or several messages:
* *_MessageIn_*: It represents the client request.
* *_MessageOut_*: It represents the provider response (used only for [InOut exchange pattern|easyesb:Transporter service model]).
* *_MessageError_*: It represents the provider error (used only for [InOut exchange pattern|easyesb:Transporter service model]).
* *_MessageAck_*: It represents the acknowledgement of provider (used only for [InOnly exchange pattern|easyesb:Transporter service model]).
A message contains these following items:
* *_An header_*: That contains meta-data to manage the routing of exchange or others non-functional aspects such as security, reliability or transactional features.
* *_A body_*: That contains the xml payload of client request or provider response.
* *_Attachements_*: That contains all attachments provided with the messages.
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