Recently engaged in the design and development of workflow engines, ready to start in learning standards, thus deepering the workflow. As the saying goes, "teaching is long", I hope to discuss together and grow together. If there is an error or copyright issue in the text, please point out, thank you! XPDL is an XML workflow definition language that makes WFMC developed an international standard, which is desirable to establish a unified standard, and through this standard, you can make different process engines to make each other. The metamodes defined by the WFMC workflow are as follows: The boxes in the figure, we call the entity (entity), where Activity is translated into activities, participant translate into participants, Relevant Data translates into association data.
1.1. XPDL entity overview data model presents the most basic composition entity in the definition of workflow, and the following is a brief introduction to each entity:
1.1.1. Workflow definition workflow defined as other entities in the workflow provides the context description, including your own information, processes, and managers, or data that requires the process run, such as initialization parameters, process Restriction time, checkpoint, people who need notification, etc.
1.1.2. Workflow Activity (Activity) Workflow is composed of one or more activities, each activity consists of a logical, self-contained work. The activity is reflected in the work, and the work can be involved, or it can be a computer application. Other optional information contains whether the activity is automatically started or ended by the process management system, and the activity of the activity to the resource relative to other activities in the same process can also specify special associated data in the process, or it can be specified as a Subflow. A activity can contain a sub-process, the subflow can be parsed by the same process engine, or it can be a remote call other process engine resolution. Subflow definitions clearly include activities, trastings, participants, and other information. The associated data in the sub-process can be input and output as a subflow. Activity can include a movable block, which performs a group of activities, events, and activities, with transition sharing the same namespace.
1.1.3. Transition information activity and activity are connected by transition. A Transition has three parts, starting activities, TO-Activity, and Convection, the Transition between the connection activity and the activity can be accessed by the conditional judgment. Transition can connect serial or parallel activities. Transition's connection type has two kinds of split and join. Split refers to the type that is divided by the activity, and join is a type connected to the activity.
1.1.4. Workflow participants define participants to define executives of each level, and participants can provide a pre-defined person or a computer application or a computer device. When the participant is a person, it is not necessarily a person or a group of people.
1.1.5. Resource library resource library allows participants to be people, equipment or applications, classic repositorys are organizational models.
1.1.6. Workflow Application Defining a workflow application is a workflow, or an application that can call or an interface. These applications may be devices, other applications in the enterprise or interface. The workflow application definition refers to the application or interface to the Workflow Engine, which contains the parameters that you need to pass.
1.1.7. Workflow Relation Data Process Performing Document Execution Process Generation Or Use, these data may act on activities during operation, or may be data used to display, or it is used to determine activity and activities. The data of the condition between the transition may also be the user's data. XPDL defines the basis or complex type of associated data, activity, applications, and the conditions in the transition will reference this. 1.1.8. System and environmental data system and environmental data are maintained by a workflow management system or local system, which can be accessed, and it is also user TRANSITION. Judging.
1.1.9. Data types and expression workflow models define a set of data types, such as characters, reference, integer, floating point, date, etc., which will be used to define associated data, environmental data, and Participant data. Through these types of data, the conditions in Transition can perform expressions. The data type can be expanded through XML or extended resource.
1.1.10. Process is shown in the packet, the process consists of a wide variety of entities, usually, participants, associated data frequently referenced by multiple flows. The data model presents the use of a library of various types of entities that associate a workflow management system to control various types of entities of the process. Package is a container containing some public properties, such as author, version, status, etc. Each process definition in the package can inherit these public properties, if they define themselves, they will no longer inherit. There will be some global entities in the package so that other processes can be referenced, these entities are generally: N Workflow Participants N Workflow Application Definition N Workflow Association Data Definition Pack Allows the internal definition of the package, or other Pack defined things, such as: the process ID in other packages as sub-process N workflow participant definition
