A Resource-Oriented Workflow Engine Based On REST

Workflow engine is a scheduling tool which is used by the enterprise to connect and integratescattered applications into a complete process application. With the rapid development of the cloudtechnology, more and more enterprises tend to release and use WebService application deployed in theclouds. And the workflow engine used to schedule these applications is altering from traditional,single-core and local to easier integrated remote application and service-oriented.A new idea is offered from the ROA (Resource-Oriented Architecture) to the workflow engineof the clouds. General HTTP access protocol is used by the REST (Representational State Transfer) serviceframework. Without any other structure on the protocol, the access to the workflow engine will besimplified well. The resource structure and URI localization are used by the REST service. In this way, theelements of workflow engine will be created and used more agilely. The resource in the engine will bebetter operated by using the resource state transfer mechanism. The resource-oriented and RESTfulframework is used in this paper to propose the resource-oriented workflow engine based on the REST.Through changing the engine to REST service, the service can be released to the remote and called by thecustomers with a general standard interface. Through making the elements of the workflowresource-oriented, each process element encapsulated as the resource can be released, created, modifiedand reused independently. Each process element can be operated and managed flexibly by the customerswithout worrying the reuse of the process details.. The main research work as follows:(1) Design workflow engine framework based on the REST style.Build the REST-style workflow engine to make the engine itself as a service which can be access byusers. The framework is divided into three levels. The resource model layer is the foundation of resourceworkflow engine.The resource model layer turn the workflow elements into resources and build a resourcemeta-model architecture; the REST engine scheduling layer design the process management, workflowtask executor which has ROA framework features; the outside service interaction layer design a set ofheterogeneous information conversion tools to solve the problem of the interaction between Web serviceswith different structure. (2) Design resource system to describe the workflow elements.Build a set of resource meta-model system with inherite. First, build a parent node model. Then builddifferent workflow elements into different resources meta-models according to the different characteristicsof the resources. These meta-models inherited from the parent node, so the resources have unifiedarchitecture to be matched and managed. Each resource has the respective characteristics. Designedphysical resources and data resources which can be judged through the relationship between two activenodes whether they can be connected.This is the basis of the workflow elements reuse.(3) The middleware used scheduling resource is proposed.The resource scheduling middleware is divided into three levels. The first level is resource meta-modelparser which is used to analyze the meta-model and parse the access to the resource into specificcommands. The second level is process administrator which is responsible for the scheduling andmanagement of the process resource according to the specific commands. The last level is resourcesactuator which is used to assign tasks and link the Web service provided by the SAAS applicationdevelopers.In the end, a resource-oriented workflow engine based on REST is designed and implementedaccording to the method in this paper. The Web services of different platforms are integrated into an orderdelivery process by using this engine. Preliminary results show that the Web services of different platformscan be integrated efficiently and the workflow elements stored in the resource library can be reused well. Inaddition, the running of the resource-oriented process can be controlled effectively in this system.Theresource-oriented workflow engine proposed to put forward a new architecture and reuse method whichhas certain reference value.