The BPMN Rule Engine uses Conditional Events to evaluate a business rule. This is a powerful mechanism to describe rules in a BPMN model and evaluate a given workitem.
The BPMN Rule Engine provides an easy way to describe also complex business rules based on a visual model. The rules are evaluated as a chain of conditional events. The engine evaluates the data of a given workitem.
To initialize a BPMN Rule Engine a Imixs BPMN Model instance need to be loaded first.
The model instance can either be taken from a running instance of the Imixs-Workflow engine or loaded on demand from the file system:
// load BPMN model from input stream
Model model = BPMNParser.parseModel(inputStream, "UTF-8");
The workitem can contain any kind of data to be evaluated by the business rules. Internally the Imixs BPMN Rule Engine is based on the Core-RuleEngine which supports various script languages to describe a rule.
Today we released version 5.0.2 of the Open Source Workflow Engine Imixs-Workflow.
The new release includes – beside the general new support of Eclipse Microprofile – some important new features. The main feature of this release is a new implementation of Imixs Adapter API. This API supports now two kinds of adapter interfaces.
The SignalAdapter can be used to implement a fine grained control of the event processing life cycle.
The GenericAdapter interface provides a model independent extension point to implement generic API features.
One of the first implementations is the new AccessAdapter class. This adapter controls the ACL defined by the Imixs-BPMN Model definition. This adapter can also be a good starting point of custom generic adapters.
Together with the Imixs Plugin API the Adapter API now provides developers with a strong and flexible extension mechanism to implement all kind of human-centric and microservice based workflow applications.
With the upcomming version 5.0.0 the Imixs-Workflow engine is integrated into the Eclipse Micoroprofile API.
The Enterprise Java technology has evolved with the industry for nearly two decades to support distributed application architectures based on RMI/IIOP, Web Services, and REST. The MicroProfile is the next step in that evolution. Since Imixs based on Java Enterprise technology stack, it is consistently to expand the technology to the new standard. As a developer this will bring you more features and a much smarter way to run the Imixs-Worklfow engine within a microservice architecture.
The Version 5.0.0 will provide the following APIs:
Metrics – This allows you to monitor Imixs-Workflow with Tools like Prometheus or Grafana
Health Check – The Health Check API can be used to probe the state of an Imixs-Worklfow instance from another machine (i.e. a kubernetes service controller)
Config API – Configuration data can now come from different locations
We will provide soon more documentation and examples on how you can run Imixs-Workflow in a Microservice Infrastructure. If you have questions please joint our community!
The hexagonal architecture is a design pattern introduced by Dr. Alistair Cockburn. A hexagon is a closed body and according to his pattern, an application is assumed to be a hexagon. Whatever is relevant to the business logic of an application gets to reside inside the hexagon and the rest is arranged outside. In this way, the business logic can be easily tested without worrying too much about external factors. So and this matches perfectly into the world of microservices.
Microservices become the new disruptive technology for software development in it’s traditional way. It is the architectural style which brings up a new way to build software systems. The Microservice Architecture evolves very fast and in deed has a lot of success.
But there are also some disadvantages in Microservices. One of the critical parts is the rising complexity within a microservice architecture. It is a problem which is often overlooked in the beginning when all this euphoria lies within a greenfield project. And the problem is often denied for a long time by its advocates. But why does this happen?
The Imixs-Workflow project supports now a native integration Adapter for Apache Kafka. With this feature asynchronous messages can be handled within a complex business process.
Apache Kafka is a distributed streaming platform. This means you can publish and subscribe to streams of records, similar to a message queue or an enterprise messaging system. Apache Kafka store streams of records in a fault-tolerant durable way and process streams of records as they occur. Kafka is generally used for two broad classes of applications:
Building real-time streaming data pipelines that reliably get data between systems or applications
Building real-time streaming applications that transform or react to the streams of data
The Imixs-Kafka Adapter integrates Kafka in a native way and allows the producing and consuming of Imixs-Workflow Messages.
Workflow Message Autowire
With Imixs-Kafka you can easily setup a scenario where Workflow Messages are generated automatically during the processing life-cycle. With the Autowire-Function new process instances are send into a Kafka Message Queue so that any consumer interested in workflow events can consume the message and react in various ways.
The Adapter filters Workflow events by the Model Version number so you can control which kind of workflows are send into a message queue.
Workflow Messages based on Business Logic
Another way to send Workflow Messages into a Kafka queue is the Imixs-Adapter Class. This implementation is based on the Imixs-Adapter concept and allows a more fine grained modeling of an asynchronous service integration. The Imixs-Kafka Adapter can be configured directly in a BPMN 2.0 Model.
This modeling approach allows you to setup complex workflow scenarios with a asynchronous communication.
Sending Workflow Events With Kafka
The other way to integrate Imixs-Workflow into a Kafka infrastructure is to send Workflow Messages to a Kafka queue to be processed by the Imixs-Workflow Instance. In this way a client sends a Process Instance with a predefined topic into a Kafka Message queue.
Imixs-Workflow will automatically consume those messages and process the workflow data. In this way messages can be used to trigger the event-based Imixs-Workflow engine. The following example shows how a client can send a workflow event for a named topic:
The Imixs-Kafka Adapter is a powerful feature to integrate Imixs-Workflow in a Microservice Infrastructure based on Publish-Subscribe Messaging Queues. With Apache Kafka a fault-tolerant and scalable messaging platform can be adapted to Saga Transactions based on a BPMN 2.0 model.
If you have any questions or your need help to integrate Imixs-Workflow into your Microservice Architecture you can join the project on Github.
The ‘Business Process Model And Notation’ standard is a well designed notation for describing business workflows. BPMN 2.0 becomes the standard for modeling business logic and fits very well the model driven software design in agile software projects.
The BPMN language, which is based on XML, was intended for users at all levels, from the business analysts who create the initial design, to the developers who implement the technical details, and finally, to the business users responsible for managing and monitoring the processes. BPMN 2.0 has evolved to become a complete specification trying to fit the needs to all people involved in the design of a business process. But writing BPMN in XML and visualizing business processes becomes nearly impossible without the use of a graphical tool.
Today we released the new Version 4.5.0 of Imixs-Workflow. The version now has a full support of Java EE7. The release also includes also several improvements in JSF components and The Rest-API. Here is an overview about the latest changes:
The XMLItem now supports mixed value lists
New Extend FileData Object with custom attributes
LuceneUpdateService – provides a new ItemAdapter class to improve the extension mechanism
Full Java EE7 Support
Performance improvements for the imixs-faces module
RestService supports now custom reports to open spread sheets
JobHandlerRebuildIndex – allows to overwrite the Block_Size and Time_out