这增加了实现复合服务的复杂程度。
This makes an implementation of composite services more complex.
图7用事件实现复合服务。
图5编程实现复合服务。
复合服务可以看作是整体方案的一种配分机制。
Composite services can serve as a partitioning mechanism for overall solution.
最后，我们建议使用编制引擎来实现复合服务。
Finally, we recommend usage of orchestration engines for service composition implementation.
涉及几个公开了的复合服务操作的解决方案图。
Solution diagram involving exposed composite service operations.
复合服务代表了一系列底层服务的单一访问入口。
The composite service represents a single point of access to the set of underlying services.
服务提供者可通过复合服务来增加价值。
It allows service providers to add value through service composition.
为了简便起见，现在，我们将复合服务分成两种。
Simplistically, for now, we will break composite services into two flavors.
复合服务为重用现有的服务提供了一种自然的方式。
The composite service provides a natural way of reusing existing services.
另一种实现复合服务的可能方式是基于事件的复合。
Another possible approach to the implementation of composite services is event-based composition.
复合服务：服务d代表最复杂的情况——复合服务。
Composite service: service D represents the most complex case — the composite service.
第四级的简单服务通常会被复合服务替代，后者可以进行组合。
Often the simple services of level four are replaced by composite services that can be choreographed.
通过更换一组服务订阅的主题，可以完全改变复合服务的实现。
By changing a set of services, subscribed to a particular topic, it is possible to completely change implementation of composite services.
复合服务在SOA实现中扮演了重要角色，它带来了以下优点。
Service composition plays a significant role in SOA implementations by providing the following benefits.
编制语言是实现编制得更好选择，也因此简化了复合服务的实现。
An orchestration language is better suited for implementation of the orchestration, which usually simplifies composite service implementation.
对复合服务的任何改变都必须重新编写服务中介者的实现。
Any change to composite service requires explicit reprogramming of the service mediator.
内建支持编制实例和上下文的编制引擎，这是实现复合服务的必须。
An orchestration engine natively supports orchestration instances and context, required for implementation of composite services.
在本文中，我们将分别从设计和实现两方面讨论复合服务的主要方式。
In this article we will discuss the main approaches to service composition, both from design and implementation point of view.
每个参与的服务(成员服务)都可以(部分地)执行复合服务(图4)。
Every participating service (component service) can execute (partial) composite service (Figure 4).
支持服务上下文的需求通常要求为每个复合服务创建特别的数据库。
Requirements to support service context usually require creation of a specialized database for every composite service to support service context.
无论你是在开发复合服务还是原子服务，都会对服务的粒度有所影响。
Whether you are developing composite services or atomic services also has an impact on the granularity of your services.
这样的话，您就可以将这些服务包装成新的复合服务来安排和编排较低级的服务。
If so, you have an opportunity to wrap them up into new composite services that orchestrate or choreograph the lower level services.
图8用编制引擎(Orchestration Engine)实现复合服务。
Figure 8 Implementing composite service using orchestration engine.
在复杂和复合服务中，多个组件必须在相同级别上以一致的方式放在一起并进行集成。
In complex and composite services, multiple components must be brought together in a consistent fashion at the same level and integrated.
在基于中介的会话复合服务中，中介者按照消费者的输入实现服务状态和状态的转换。
In the case of mediator-based conversational services, the mediator implements service states and states transitions, based on the consumer inputs.
一种是基本的复合服务，即一个被包装成单个服务请求的常用服务请求的集合。
A basic composite service is nothing more than a commonly used set of service requests wrapped up into a single service request.
必须创建一些复合服务来管理可在更长一段时间（可能数天，甚至数个星期）延展的过程。
Some composite service are inevitably created to manage processes that stretch over a much longer time span of perhaps days or even weeks.
综上所述，在前面讨论的三种方式中，基于编制的实现看起来是创建复合服务最可行的方式。
Based on the above, out of the three discussed approaches, the orchestration-based implementation seems to be the most viable way for creation of the composite services.
复合服务的实现要求实现某种形式的事务支持，来确保参与的服务在失败时仍然有正确的行为。
The composite services implementation requires implementation of some form of transactional support to ensure correct behavior in the case of failures of participating services.
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