The specification defines a message exchange protocol between the BPEL engine and a task component.
这个规范定义了BPEL引擎和任务组件之间的消息交换协议。
The WS-Addressing policy type is required if you are to use an asynchronous message exchange protocol.
如果要使用异步消息交换协议，需要WS - Addressing策略类型。
A synchronous message exchange protocol is the easier approach to implement and has the least impact on the service provider environment.
同步消息交换协议更容易实现，对服务提供者环境的影响也最小。
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