Red Hat Decision Manager 7: Part 3-1 A DMN Introduction

In this video, I am going to give a short introduction to DMN. I shall describe what its capabilities are and why is it important. To fully describe how DMN works will require a much longer video than this one. You can find more details on DMN using the links provided in the description of this video.

Here is a brief description of DMN, by no means comprehensive but sufficient for you to know why it exists and help you understand the demo in the next video.

DMN is an OMD standard. OMG or the Object Management Group is the same organisation that brought you BPMN2, the Business Process Model Notation V2 standard. DMN is to decision modelling what BPMN2 is to business process modelling.

When you create a DMN model, you are creating a DRD or Decision Requirement Diagram. It is a visual representation of your DMN model. FEEL or Friendly Enough Expression Language is used to evaluate expressions eg, in a decision table. It has been said that: If you can use Microsoft Excel formulas, you will have no problem learning and using FEEL. There is a meta model interchange meaning that you can export your model as XML and import your model to another DMN tool.

To make model interchange possible, the DMN specs defines 3 conformance levels ranging from level 1 to 3 where level 3 is the highest.

The DMN Technology Compatibility Kit shows the compatibility and conformance level of DMN products available on the market, Red Hat Decision Manager included.

To learn more, please watch the video:


A Load Generation Framework for CEP Application Testing and Demos


1 Introduction

Have you ever lamented over how difficult it is to test a CEP application, let alone doing a demo? Common challenges include:

  • How to generate events for testing a CEP application?
  • How to demo a CEP application?
  • Cannot be real-time, it takes too long
  • Lack of infrastructure during demo
  • Need repeatable outcome

In this article, I am going to show you a framework that I developed which allows you to define external events in a CSV file, play them back to your CEP application in demonstrations in accelerated time. This framework can also be used to generate a large volume of events based on event arrival distribution either in realtime or accelerated time to load test your CEP application. It is such a versatile tool that you can even use it to perform discrete event simulation (not described in this article).

The framework solves all the problems listed earlier by allowing you to:

  • Configure load to drive your CEP application
  • Run your CEP application in accelerated time
  • See the results quickly
  • Use it as a reusable infrastructure for CEP application testing and demos
  • Achieve repeatable outcome

Examples will be provided to showcase the capabilities of the framework including playing back configured events for a CEP application and realtime load generation using JBoss Fuse/A-MQ and event arrival patterns (distributions).

This article is divided into the following main sections:

  • The Optometrist CEP Application – this CEP application shows how to configure individual events to drive the CEP application in a CSV file.
  • The Stock Price CEP Application – this is a simple CEP Application which illustrates the event generation capability based on event arrival distribution.
  • Realtime Load Generation via Fuse and A-MQ integration – this section illustrates how realtime load generation can be achieved running multiple instances of the load generator to feed the Stock Price application via Fuse and A-MQ by applying software design patterns to loosely couple the load generator and the CEP application.
  • How it works – shows the UML class diagram containing the load testing framework classes, their attributes, operations and relationships. It also describes how the framework works including how the load generator is loosely coupled to your CEP application using the Observer design pattern.

The first few sections give you an overview of the capabilities of the framework. The “How it works” section outlines how the framework works. Continue reading A Load Generation Framework for CEP Application Testing and Demos

Building a JBoss BPMS Web Application using jBPM Form API

(This article assumes some basic knowledge of the JBoss BPM Suite including using Business Central.)

JBoss BPMS forms are generated and customised by business analysts when they create business processes. The forms are usually used for kicking off a business process instance and interacting with the user when the process reaches a user task eg, for a manager to manually approve a loan. Few customers use the forms on the BPMS Execution Servers. They prefer to build a web application that interacts with a business process remotely running on a BPMS Execution Server to gain fine-grained access control, consistent look-and-feel and better client interaction. The main issue is how to use the forms generated on the BPMS server from the web application. There was no easy way to do that until the recent release of JBoss BPMS 6.1. Continue reading Building a JBoss BPMS Web Application using jBPM Form API

Robot Programming using JBoss BRMS

One of my hobbies is building robots. After programming several robots, I say to myself: there’s got to be a better way of doing this. You program the behaviour of a robot using a micro-controller. Every time you want to make a change, you have to re-flash the on-board non-volatile flash memory. If you compare this practice with enterprise applications, it is similar to that of many older enterprise applications which embed business logic in code. The solution is to move the embedded business logic (in our case, the robot behaviours programmed on micro-controller) out to be managed and executed by a business rules engine. This is exactly what I did. And I call my robot CepBot. Continue reading Robot Programming using JBoss BRMS

Building a JBoss BPMS Rules Application without Writing Code

This article assumes some basic knowledge of the JBoss BPM Suite including using Business Central.

JBoss BPM Suite (BPMS) and JBoss Business Rule Management System (BRMS) 6.1 introduced a new component called the Real-time Decision Server (RTDS). Rule projects built using BPMS can be deployed directly onto the Real-time Decision Server via Business Central. Applications can instantiate and execute rules on the RTDS using either a REST or JMS interface.

In this article, I am going to show you how you can build a rule-based application without writing even a single line of Java code. The application aims to rate locations for placement of mobile speed cameras. It is an example application I made up and is not being used by any Police Departments. My simplified speed camera placement rating criteria are based on: Continue reading Building a JBoss BPMS Rules Application without Writing Code