基于服务的工作流管理

【作者】 俞镇；

【导师】 吴朝晖；

【作者基本信息】 浙江大学 ， 计算机应用， 2004， 硕士

【摘要】 作为一种已被深入研究和广泛应用的成熟技术，企业内的工作流管理系统已经能够很好的实现组织成员间的协同工作以期达到业务的整体目标。但是，随着新的基于Internet的网络应用的发展，出现了许多企业间的业务流程。为了对这些流程进行的管理，就出现了跨企业的分布式工作流管理系统。在支持跨企业工作流管理的工作流互操作模型中，基于Web Service和Grid Service等技术的松散耦合的工作流互操作模型由于其具有的灵活性，正越来越多的被使用。但是，现有的这些模型仍然存在一些不足之处。其中，一个共同的问题就是这些模型往往将一个服务内部结构完全被屏蔽，使得由这些服务组成的流程的整体结构也无法获得，这样，就难以定义和管理服务组合成的流程。 对于这个问题，本文提出了一个基于服务的工作流模型，这个模型从控制流的角度，将一个服务的内部流程结构分为公开和私有两部分。其中，私有部分是详细的服务结构，而公开部分则是与服务私有部分满足一定的关系的，服务结构的一个简化版本。通过发布服务的公开部分，跨企业流程的定义者和管理者可以将各企业提供的服务组合成一个跨企业流程。在这个模型中，定义了一个基于服务的工作流基本模型，以及在这个模型中的一系列基本操作。由这些操作再引出服务的输入输出等属性，再根据输入输出定义了服务间的接口等价关系，并将这个关系作为一个服务的私有部分和公开部分应具有的关系。在定义了这个关系后，还对这个关系具有的一些性质进行了讨论和证明，并且在此基础上讨论了接口等价关系在流程结构分析方面的作用。同时，还讨论了基于服务的工作流时间管理。这里，采用与定义接口等价关系同样的思路，提出一个基于服务的工作流时间模型，并在此基础上讨论了工作流时间管理的几个问题，提出了相关的算法。 在理论模型的基础上，本文又提出了一个流程驱动的服务管理系统。这个系统以服务为基础，提供了服务管理模块，对服务的定义，创建，注销和运行进行管理，并提供了对服务持久化和事务管理的支持。在这个系统中，开发者可以在服务基础类之上开发自己的服务类，以获得对服务进行灵活扩展能力，处理复杂的业务关系。在服务管理的基础上，系统还有应用集成和任务管理这两个扩展模块。这两个模块为系统增加了管理异质应用和需要由人员参与的任务的功能。在服务集成，应用管理和任务管理的基础上，流程管理作为系统的主要功能模块，为服务提供了定义，执行和管理长时间操作的能力。同时，在这个系统中，一个流程又可以被包装成一个流程服务，可以使用服务管理所实现的功能。由于一个流程涉及应用，任务和服务等多方面内容，还详细的分析了一个流程服务所需具有的基本元素，支持的主要操作，对外提供的基本接口等内容。为了支持多个系统的服务间的互操作，系统提供了流程服务的描述，发布，注册和查找机制。使用这些机制，一个系统可以找到其需要的在远程系统上的服务。更多还原

【Abstract】 As a deeply researched and widely used technology, intra-enterprise workflow management systems are now able to coordinate the members of an organization to attain the overall objective of business. However, with the development of new Internet-based applications, there are emerging many inter-enterprise processes. Thus, inter-enterprise distributed workflow management systems are introduced to manage those processes. Among the workflow models of interoperability, the web service based and grid service based loosely coupled workflow models of interoperability are becoming more and more widely used for their flexibility. Nevertheless, those models also have their weakness. A common problem of them is that those models often encapsulated all the structures of a service and makes it hard to get the whole structure of the process composed of those services. Therefore, it is difficult to define and manage processes that consist of services.For this problem, this paper presents a service-based workflow model. From the perspective of control flow, this model divided a service into two parts, private part and public part. The private part is the detailed structure of the service while the public part is a simplified version of the service structure. By publishing the public parts of services, the service providers enable the designers and managers of inter-enterprise processes to compose provided services into an inter-enterprise process. A focus here is how to define the relations that the public part and private part of a service should have. This model defines a basic service-based workflow model and a set of basic operations in it. Then, based on this model, it defines interface equivalent relation, which is used as the relations that the private part and public part of a service should have. After the definition of this relation, some attributes of this relation are discussed and proved. Based on those attributes, some applications of interface equivalent relation in the analysis of process structures are presented. Moreover, time management in service-based workflow management are also discussed. Following the similar ideas of the definition of interface equivalent, a time model for serviced-based workflows is proposed, based on which some related problems on time management in service-based workflows are discussed.Based on this model, this paper then proposes a process-driven service management system. This system provides service management modules to define, create, remove and run services. This module also supports persistence management and transaction management for services. In this system, developers can develop their own classes derived from service base class, which extends the ability services. System also has two extended modules, application integration and task management, which provide system with the ability to integrate heterogeneous applications and manage tasks that are participated by users. Based on application integration, task management and service management, process management, the major module of this system, enable system to define, run and manage long time operations. Also, a process can be encapsulated a process service and utilize the functions of service management. To support interoperations among services in different systems, system has mechanisms to descript, publish, register and find services.更多还原