异构服务组装执行引擎的设计及关键技术研究

【作者】 禚玉芹；

【导师】 陈松乔；

【作者基本信息】 中南大学 ， 计算机应用技术， 2008， 硕士

【摘要】 软件技术的迅速发展,促使服务的类型和数量不断增加,造成网络上存在大量动态、异构的服务资源。如何将这些资源有效组织,完成功能更强大、更完整的应用需求,成为当前服务组装研究的热点。工作流技术在流程驱动方面具有协调各种应用、处理过程自动化等特点,被广泛用于服务组装过程中的流程调度。然而,目前的工作流引擎普遍缺乏对异构服务组装资源动态、异构的支持,本文针对这种不足,设计了一种面向异构服务的执行引擎。活动的状态是流程调度过程中与活动联系最紧密的属性,本文充分利用活动的状态信息,设计了基于状态驱动的活动调度机制。定义活动触发的三个使能条件:控制使能、参数使能和自定义使能,通过使能条件衡量活动实例的状态,当活动触发的使能条件满足,服务实例被驱动,服务的驱动带来控制的转移和参数的传递,促使下一个服务触发的使能条件满足,如此带动流程执行的推进。其次,流程的调度执行是数据流和控制流共同作用的结果,而数据流的转移是通过参数的传递实现的,参数传递的关键是确定源参数与目标参数的唯一绑定关系。本文从参数名称和参数类型两个方面进行分析,通过基于语义相似度的参数匹配,确定参数间源参数到目标参数的绑定关系,并通过实例介绍了参数绑定的过程。最后,执行引擎良好的容错机制是服务组装平台稳定运行的重要保障。本文对异构服务组装中出现的故障进行分类,按照故障对流程的影响分为暂时性故障和永久性故障,针对这两种情况分别采用基于代理的二次驱动和面向事务的服务替换策略,对故障进行屏蔽。更多还原

【Abstract】 The rapid development of software technology, contributes to the increasing of services in type and quantity, and also causes emerging of many dynamic, heterogeneous services on the network. How organize these resources effectively to turn them into more powerful, more complete application requirements, is the hot spot of current services composition. Because workflow has many characteristics such as coordinating applications, processing automation in process-driven technology, so it has been widely used in the process of services composition. However, the workflow engine to a general lack of the support for dynamic, heterogeneous services, this thesis designs a heterogeneous service-oriented engine for services composition to these limitations.The state of activities is a property most closely associated with the activities in the process of services composition. We take full advantage of the state information, and design a state-driven mechanism for scheduling activities. Defining three enable conditions that can trigger activities: enable condition for control, parameters and user-defined. So the state of activities can be measured through these conditions. When the trigger conditions of activities can be met, services being driven, service-driven brings about the transfer of control and the transmission of parameters, and triggers the next service under the conditions that can be met, so lead the implementation process to further advance.Second, the scheduling of process is the the common results of the data flow and the control flow, and the data flow is carried out through the transfer of control and parameters. The key of parameters transmission is to determine the only source of the binding relationship. This thesis analysis from two sides: the name of parameters and the type of parameters, determines the binding relationship of source and aim by matching the parameters based on the semantic similarity, and introduces the binding process through examples. Finally, a good fault-tolerant mechanism is an important safeguard for stable operation of services composition platform. The exceptions in the process of heterogeneous services composition are divided into two sorts in accordance to the impact, and are both given the different solution: the second driving based on agents and service-oriented replace.更多还原