Study Of Design And Implementation Of Workflow Enactment Agent In Migrating Workflow Management System

The migrating workflow, which is proposed based on the mobile computing model, is a new direction within the workflow management research In light of the complexity of the business process goal, the workflow is mapped to one or more migrating instances, which are the main execution bodies. Each migrating instance is corresponding to a single business sub-process and can complete one or more tasks with local services and resources in one workplace. Multi migrating instances complete the whole business goal by migrating and cooperation with the support of anchorage server. If the current workplace can' t afford the further task execution, migrating instance will migrate to the next workplace for continuous execution with the task specification and previous execution results.A framework was proposed in the document [2] for the migrating workflow management system, which composes of migrating instances, workplaces and migrating workflow management engines. Workplace stands for the department or the organization which participates in the workflow, which has an anchorage server and work-machines LAN bound with it. Anchorage server is where migrating instances park and get workflow services. Workplace is where the actual workflow services are provided. To implement the light-weighted migrating instances and advance the security of workplace, document [4]proposed the advice to set up an enactment Agent for migrating instances in study of anchorage server. The paper presents research on the mechanism of workflow service enactment Agent, proposes the conceptual model for the workflow enactment Agent, validates it's feasibility and completes the further design and implementation according to the reference architecture of migrating workflow system and the model of anchorage server. Workflow enactment Agent is deployed in the anchorage server. It receives the task delegation from migrating instances and completes one or more tasks for migrating instances according to the task logic delegated by migrating instances and local service rules. The import of workflow enactment Agent totally isolated the migrating instances from work-machines network behind to make sure the security of work machine network. Further more, the function of work machines in migrating instances is transferred to anchorage server. Migrating instances are forces to hibernate while tasks are in execution. That facilitates the server to detect the abnormal actions of migrating instance and decline the attack possibilities to anchorage server by migrating instances. Code size of migrating instances can be small, which helps the light-weighted migrating.Workflow enactment Agent is composed of Service Agent Environment, Local Workflow Service Directory and Service Agents Pool. Service Agents act as the clients of background workflow services and resources. Each of Service Agents corresponds to one kind of workflow services which will be offered by the workplace. Description for the services and related interfaces are published in Local Workflow Service Directory. Service Agents Pool, the management component of Service Agents, will manage the initialization, the running state monitor of Service Agent and the maintenance of services' states. Service Agent Environment is composed by workflow task Parser, Access Control, Workflow Enactment Scheduling Engine, supplying the Service Agent with runtime environment.The analysis of the execution results of the workflow enactment Agent shows that the prototype realizes the designation objects and proves the reference model of the anchorage.