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What is Activiti workflow? in view of this question, this article introduces the corresponding analysis and answer in detail, hoping to help more partners who want to solve this problem to find a more simple and easy way.

Introduction to Workflow

Workflow (Workflow): workflow is the automatic management of business processes through computer technology. A plurality of participants are implemented to automatically execute the business process according to the predetermined process.

Definition: automate the management of business processes by computer

The main solution is the process of automatically transferring documents, information, or tasks among multiple participants according to some predefined rules. In order to achieve an expected business goal, or to promote the realization of this goal

The goal of the workflow management system is:

Manage the process of the work to ensure that the work is performed by the expected personnel at the right time

Insert human execution and intervention into automated business processes

Workflow framework:

Activiti,JBPM,OSWorkFlow,WorkFlow

The underlying workflow framework needs to be supported by a database.

Workflow terminology Workflow engine

ProcessEngine object: this is the core of Activiti's work. Responsible for generating various instances and data when the process is running, monitoring and managing the operation of the process

BPM

Business process Management:

It is a systematic method that centers on the standardized construction of excellent end-to-end business processes and aims to continuously improve the business performance of the organization.

BPM is included in common business management education such as EMBA,MBA.

BPMN

Business process modeling and annotation:

How these diagrams are combined into a business flow chart (Business Process Diagram)

Discuss the various uses of BPMN: including with what precision to influence the model in a flowchart

The value of BPMN as a standard

The Prospect of the Future Development of BPMN

Stream object

A business flowchart has three core elements of flow objects

Event

An event is described in a circle, indicating what happens during a business process

Events affect the flow of the process. There is usually a cause (trigger) or an influence (result)

Based on their impact on the process, there are three kinds of events: start event, intermediate event, and termination event.

Activity

Represented by a rounded rectangle, a process consists of one or more activities

Conditions

The condition is represented by a diamond and is used to control the branching and merging of the sequence flow.

Can be used as an option, including branching and merging of paths

The internal tag gives the type of control flow

Brief introduction of Activiti Open Source Workflow Framework Activiti

Activiti is an open source workflow engine that implements the BPMN 2.0 specification, publishes designed process definitions, and schedules processes through api

As an open source platform for workflow and business process management licensed by Apache, the core of Activiti is an ultra-fast and super-stable BPMN2.0 process engine based on Java, which emphasizes the embeddability and scalability of process services, while more emphasis is placed on business personnel

Activiti process engine focuses on the ease of use and lightweight of system development. Each BPM business function Activiti process engine is provided to the developer in the form of a service. By using these services, developers can build feature-rich, lightweight and efficient BPM applications

Activiti service structure

Activiti system service structure diagram

Core classes:

ProcessEngine: the abstraction of the process engine, through which you can obtain all the services you need

Service class:

= = RepositoryService==

= = RuntimeService==

= = TaskService==

= = HistoryService==

= = FormService==

= = IdentityService==

ManagementService

Repository Service provides access to repository

Each different version of the business process definition in Activiti requires the use of definition files, deployment files, and supporting data (such as BPMN2.0XML files, form definition files, process definition image files, etc.), all of which are stored in Activiti's built-in Repository

Runtime Service provides the functions of starting process, querying process instance, setting and getting process instance variable and so on. In addition, it provides access to process deployment, process definition and process instances.

Task Service provides operations related to Task and Form for users. It provides the functions of runtime task query, collection, completion, deletion and variable setting.

History Service is used to * * obtain the information of running or completed process instances. * * unlike the process information obtained in Runtime Service, historical information contains permanent information that has been persisted and has been optimized for queries.

Using Form Service, you can access the form data needed to start and complete tasks and render the form as needed

Both process and status Task in Activiti can correlate business-related data

Identity Service provides the management function of users and groups in Activiti system.

Activiti has built-in functions of user and group management. You must use the information of these users and groups in order to obtain the corresponding Task.

Management Service provides management and maintenance functions for Activiti process engine

These functions are not used in workflow-driven applications, but are mainly used in the daily maintenance of Activiti systems.

XxxService: obtained through ProcessEngine, Activiti encapsulates services with different lifecycles in different Service, including definition, deployment, and operation. Service information in the relevant lifecycle can be obtained through service classes.

Core business objects:

Classes under the org.activiti.engine.impl.persistence.entity package, including Task,ProcessInstance,Execution, etc.

The method of implementing the corresponding interface according to different responsibilities (inheriting the PersistentObject interface if persistence is required), which is different from the traditional entity class

Activiti component

= = Activiti context component Context:== is used to store global information with a long life cycle, similar to Application. It mainly includes the following three categories:

CommandContext: command context-saves the necessary resources for each command, such as session for persistence

ProcessEngineConfigurationImpl: process engine-related configuration information-global configuration information for the entire engine. Such as data source DataSource and so on. This object is a singleton and is initialized when the process engine is created

ExecutionContext: holds the ExecutionEntity object

= = persistence component: =

DbSqlSessionFactory: responsible for DbSqlSession related operations

GenericManagerFactory: responsible for AbstractManager related operations

DbSqlSession: responsible for the execution of sql expressions

AbstractManager: responsible for object persistence operation

Activiti uses mybatis for OR mapping, and designs its own persistence framework based on this.

Initialized when the process engine is created, the top-level interface Session,SessionFactory

Session has two implementation classes:

SessionFactory has two implementation classes:

= = Event-Listener component:

TaskListener

JavaDelegate

Expression

ExecutionListener

ProcessEngineConfigurationImpl holds an instance of DelegateInterceptor to make it easy to call handleInvocation

Activiti allows client code to intervene in process execution and provides event listening components

Type of event monitored:

= = Cache component =

There is implementation of cache in DbSqlSession

Activiti is cached based on List and Map: if you query, check the cache first. If not, query it directly and put it in the cache.

= = Asynchronous execution component =

JobAcquisitionThread

BlockingQueue

ThreadPoolExecutor

The method ProcessEngines calls the JobExecutor.start,JobAcquisitionThread thread to start work when the engine starts, and its run method continuously executes the job in the AcquiredJobs. After executing once, the thread waits for a certain time until it times out or the JobExecutor.jobWasAdded method is called because of a new task.

Activiti can perform tasks, JobExecutor is its core class, and JobExecutor contains three main properties:

Process virtual machine PVM

The process virtual machine API exposes the POJO core of the process virtual machine, and the process virtual machine API describes the necessary components of a workflow process, including:

PvmProcessDefinition: the definition of process, figuratively speaking, is the picture drawn by the user. Static meaning

PvmProcessInstance: a process instance, an instance of a PvmProcessDefinition initiated by a user. Dynamic meaning

PvmActivity: a node in the process

PvmTransition: the path that connects each node. Figuratively speaking, it is the connection line between each node in the diagram.

PvmEvent: events triggered during process execution

Activiti architecture

Activiti Engine:

The core module

Provide parsing, execution, creation, management (tasks, process instances), query history and generate reports based on results for BPMN 2.0 specification

Activiti Modeler:

Model designer

Suitable for business people to transform requirements into normative process definitions

Activiti Designer:

The function is similar to Activiti Modeler, it also provides visual design function based on BPMN 2.0 specification, but the definition of BPMN specification is not fully supported yet.

Business requirements personnel can import the process definition (XML format) designed by Signavio into Designer, thus allowing developers to further process it into a runnable process definition.

Activiti Explorer:

Can be used to manage warehouses, users, groups, startup processes, task management, etc.

This component uses REST style API to provide a basic design model. If the business is simple, it can also be used directly without development. It can also be used as the process and task management system of the background administrator.

Activiti REST:

Provide RESTful style service

Allows the client to interact with the engine's REST API in a JSON way

General protocols have the characteristics of cross-platform and cross-language.

Activiti database support

The background of Activiti is supported by database.

All tables start with ACT_

The second part is a two-letter identification indicating the purpose of the table.

The purpose also corresponds to the API of the service

ACT_RE_*: 'RE' means repository. The prefix table contains the process definition and process static resources (pictures, rules.) ACT_RU_*: 'RU' stands for runtime. These runtime tables contain process instances, tasks, variables, asynchronous tasks, and other running data. Activiti saves this data only during the execution of the process instance and deletes these records at the end of the process. In this way, the runtime table can be very slow all the time. ACT_ID_*: 'ID' stands for identity. These tables contain identity information, such as users, groups. ACT_HI_*: 'HI' stands for history. These tables contain historical data, such as historical process instances, variables, tasks. ACT_GE_*: general data. Used in different scenarios, such as storing resource files

Resource pool process rule table (ACT_RE_*:'RE' stands for repository. The prefix table contains the process definition and process static resources (pictures, rules.)

Act_re_deployment deployment information table act_re_model process design model deployment table act_re_procdef process definition data table

Run-time database tables (ACT_RU_*:'RU' stands for runtime. These runtime tables contain running data such as process instances, tasks, variables, asynchronous tasks, etc. Activiti only saves these data during the execution of the process instance and deletes these records at the end of the process. In this way, the runtime table can always be very small and fast)

Act_ru_execution runtime process execution instance table act_ru_identitylink runtime process personnel table, which mainly stores information about task nodes and participants act_ru_task runtime task node table act_ru_variable runtime process variables data table

The organization table (ACT_ID_*: 'ID' stands for identity. These tables contain identity information, such as users, groups.)

Act_id_group user group information table act_id_info user extension information table act_id_membership user and user group correspondence information table act_id_user user information table these four tables are very common, basic organizational management, it is recommended to develop your own set of user authentication The function of the component is too simple, and many requirements are difficult to meet in use.

Historical database table (ACT_HI_*:'HI' stands for history. These tables contain historical data, such as historical process instances, variables, tasks.)

Act_hi_actinst history node table act_hi_attachment history attachment table act_hi_comment history opinion table act_hi_identitylink history process personnel table act_hi_detail history details table Query act_hi_procinst historical process example table act_hi_taskinst historical task case table act_hi_varinst historical variable table with historical variables

Organization table (ACT_GE_*: general data. Used in different scenarios, such as storing resource files)

Act_ge_bytearray binary data table act_ge_property property data table stores data at the entire process engine level. When initializing the table structure, three record Activiti configuration files are inserted by default.

Activiti.cfg.xml: Activiti core configuration file, basic parameters of the configuration process engine creation tool and database connection pool parameters

Define database configuration parameters

Configure connection pool parameters

Activiti characteristic data persistence

The design idea of Activiti is simple and fast.

The bottleneck is reflected in the process of exchanging data with the database, for which Activiti chooses to make MyBatis, so that Command can be executed through the optimal SQL statement, which alone allows the engine to maintain the highest performance in terms of speed.

Engine service interface

Activiti process engine focuses on the ease of use and lightweight of system development. Every BPM business function, Activiti process engine, is provided to developers in the form of services. By using these services, developers can build rich, lightweight and efficient BPM applications.

The activiti.cfg.xml file is the core configuration file, which is integrated into the IOC container of Spring and generates a ProcessEngineConfiguration object, which is the configuration object of the process engine.

The ProcessEngine object is the process engine object, which is the core of the workflow business system. All business operations are implemented by the objects derived from this object.

The Activiti engine provides seven Service interfaces, all obtained through ProcessEngine, and supports chain API programming style

Process designer

Activiti Modeler process designer based on Web

ActiBPM plug-in for IDEA

Native support for Spring

Activiti natively supports Spring and can be easily integrated with Spring. It is very convenient to manage transactions and parse expressions (Expression).

Separate runtime from historical data

Activiti inherits from jBPM4 and follows the separation of runtime and historical data in table structure design.

This design can quickly read run-time data and read from special historical tables only when you need to query historical data. This design method can greatly improve the efficiency of data access, especially when the data is accumulated over time.

This is the end of the answer to the question about what is Activiti workflow. I hope the above content can be of some help to you. If you still have a lot of doubts to solve, you can follow the industry information channel to learn more about it.

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