Welcome!

Java IoT Authors: SmartBear Blog, Elizabeth White, Pat Romanski, Dana Gardner, Liz McMillan

Related Topics: Java IoT

Java IoT: Article

JSR 159 and Defining a Component Specification

JSR 159 and Defining a Component Specification

(October 25, 2002) - One area that I have taken a real interest in over the last year is component-based development. Currently, there is a JSR (# 159) named Java Process Component API. The status of this JSR has not reached Public Review yet. I recently had an e-mail thread with Mark Hapner from Sun, who is the spec lead for 159, and he explained that the expert group was still working on the direction that the spec was going to take.

Here is the overview of the JPC API right from the JSR detail page: "The Java Process Component (JPC) model will allow developers to directly represent a component as a service process that interacts via XML schema based events, produced and consumed through its typed ports. It will provide a facility for combining a group of process components into a collaboration that defines the linkage between their ports and their content types. It will also define a conversation mechanism that allows a developer to specify a stateful interaction sequence between ports."

"JPCs will allow developers to directly model event based services as individual components and collaborations. JPC will define both synchronous and asynchronous interaction modes. The JPC container will provide the infrastructure for life cycle management, transactions, security, content flow and content transformation. In addition, JPC containers will provide facilities for exposing JPCs and JPC collaborations as a Web service and support the use of a Web service within a JPC collaboration."

"An important goal of JPC is to enable visual tool based customization and composition of process components."

Well, after reading that, I understand why this was accepted as a JSR over a year ago and they still don't have a public draft available. However, what they do have available is a link to an existing document from the OMG that describes an Enterprise Distributed Object Computing Component Collaboration Architecture. The available document, located at http://www.omg.org/cgi-bin/doc?ad/2001-06-09, is a PDF that is nearly 500 pages long and chock-full of information on the OMG spec - this includes full UML diagrams and plenty of useful information. What this document reminded me of was reading the book Objects, Components and Frameworks with UML - the Catalysis Approach, by Desmond D'Souza and Alan Willis, which is 700+ pages.

So, what is a component and why does it take so much time and paper to define a component specification? First, let's look at a couple of definitions.

First, we will look at a definition from the Catalysis book (p. 387): "A coherent package of software implementation that (a) can be independently developed and delivered, (b) has explicit and well-specified interfaces for the services it provides, (c) has explicit and well-specified interfaces for services it expects from others, and (d) can be composed with other components, perhaps customizing some of their properties, without modifying the components themselves."

Next, we will take a look at a shorter definition from the "Developing with Apache Avalon" guide written by Berin Loritsch (http://jakarta.apache.org/avalon/index.html), that says roughly the same thing: "A Component is the combination of a work interface, and the implementation of that interface. Its use provides a looser coupling between objects, allowing the implementation to change independently of its clients." Stay tuned to this column for a future discussion of Avalon.

This leads very nicely into the last item, which is from the great book "UML Components," written by John Cheesman and John Daniels. They write (and I am paraphrasing here from pages four to six, and vastly simplifying): "So, what exactly is a component? A better question, and one that we can answer simply, is, what features does a component have and how does our view of it change during a project life cycle? It starts with a component standard, and then you have a component specification, the component interfaces, the component implementation, the installed component and finally the component object."

As you can see, a component is more than just some class that offers functionality. A component is typically some larger unit of functionality that can be manipulated, replaced, improved, etc without changing the interface by which the components services are offered. Think of a Rule Engine as being a prime candidate for componentization, or perhaps a Workflow engine. In fact, let's break down a workflow engine even further and say that a workflow engine can be comprised of a Resource Allocation component among other things and the composition of those components provides workflow functionality.

What we have today with JavaBeans and Enterprise JavaBeans - these are two component standards - specifications for the components themselves. One of the main goals that the Process Component API aims to do is provide a specification for component interaction, truly a great addition for Java Component Based Development (CBD).

I would be curious to hear if people are interested in this API, whether or not people are actively engaged in CBD, and what standards and specifications you are using. Please e-mail me at [email protected].

More Stories By Jon Strande

Jon Strande is a consultant with Perfect Order in
Harrisburg, PA. Jon is a Java Certified Programmer who
has written several articles on Java and was the past
president of his local JUG.

Comments (1) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Jan Venema 10/29/02 04:09:00 PM EST

I used to think of OO en CBD that it would one day be possible to design my own wordprocessor just by writing recepies that combine components into applications.

@ThingsExpo Stories
The IoT has the potential to create a renaissance of manufacturing in the US and elsewhere. In his session at 18th Cloud Expo, Florent Solt, CTO and chief architect of Netvibes, will discuss how the expected exponential increase in the amount of data that will be processed, transported, stored, and accessed means there will be a huge demand for smart technologies to deliver it. Florent Solt is the CTO and chief architect of Netvibes. Prior to joining Netvibes in 2007, he co-founded Rift Technol...
The increasing popularity of the Internet of Things necessitates that our physical and cognitive relationship with wearable technology will change rapidly in the near future. This advent means logging has become a thing of the past. Before, it was on us to track our own data, but now that data is automatically available. What does this mean for mHealth and the "connected" body? In her session at @ThingsExpo, Lisa Calkins, CEO and co-founder of Amadeus Consulting, will discuss the impact of wea...
SYS-CON Events announced today that Peak 10, Inc., a national IT infrastructure and cloud services provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Peak 10 provides reliable, tailored data center and network services, cloud and managed services. Its solutions are designed to scale and adapt to customers’ changing business needs, enabling them to lower costs, improve performance and focus inter...
We’ve worked with dozens of early adopters across numerous industries and will debunk common misperceptions, which starts with understanding that many of the connected products we’ll use over the next 5 years are already products, they’re just not yet connected. With an IoT product, time-in-market provides much more essential feedback than ever before. Innovation comes from what you do with the data that the connected product provides in order to enhance the customer experience and optimize busi...
In his session at @ThingsExpo, Chris Klein, CEO and Co-founder of Rachio, will discuss next generation communities that are using IoT to create more sustainable, intelligent communities. One example is Sterling Ranch, a 10,000 home development that – with the help of Siemens – will integrate IoT technology into the community to provide residents with energy and water savings as well as intelligent security. Everything from stop lights to sprinkler systems to building infrastructures will run ef...
So, you bought into the current machine learning craze and went on to collect millions/billions of records from this promising new data source. Now, what do you do with them? Too often, the abundance of data quickly turns into an abundance of problems. How do you extract that "magic essence" from your data without falling into the common pitfalls? In her session at @ThingsExpo, Natalia Ponomareva, Software Engineer at Google, will provide tips on how to be successful in large scale machine lear...
Digital payments using wearable devices such as smart watches, fitness trackers, and payment wristbands are an increasing area of focus for industry participants, and consumer acceptance from early trials and deployments has encouraged some of the biggest names in technology and banking to continue their push to drive growth in this nascent market. Wearable payment systems may utilize near field communication (NFC), radio frequency identification (RFID), or quick response (QR) codes and barcodes...
SYS-CON Events announced today that Stratoscale, the software company developing the next generation data center operating system, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Stratoscale is revolutionizing the data center with a zero-to-cloud-in-minutes solution. With Stratoscale’s hardware-agnostic, Software Defined Data Center (SDDC) solution to store everything, run anything and scale everywhere...
Angular 2 is a complete re-write of the popular framework AngularJS. Programming in Angular 2 is greatly simplified – now it's a component-based well-performing framework. This immersive one-day workshop at 18th Cloud Expo, led by Yakov Fain, a Java Champion and a co-founder of the IT consultancy Farata Systems and the product company SuranceBay, will provide you with everything you wanted to know about Angular 2.
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
You deployed your app with the Bluemix PaaS and it's gaining some serious traction, so it's time to make some tweaks. Did you design your application in a way that it can scale in the cloud? Were you even thinking about the cloud when you built the app? If not, chances are your app is going to break. Check out this webcast to learn various techniques for designing applications that will scale successfully in Bluemix, for the confidence you need to take your apps to the next level and beyond.
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
Increasing IoT connectivity is forcing enterprises to find elegant solutions to organize and visualize all incoming data from these connected devices with re-configurable dashboard widgets to effectively allow rapid decision-making for everything from immediate actions in tactical situations to strategic analysis and reporting. In his session at 18th Cloud Expo, Shikhir Singh, Senior Developer Relations Manager at Sencha, will discuss how to create HTML5 dashboards that interact with IoT devic...
Artificial Intelligence has the potential to massively disrupt IoT. In his session at 18th Cloud Expo, AJ Abdallat, CEO of Beyond AI, will discuss what the five main drivers are in Artificial Intelligence that could shape the future of the Internet of Things. AJ Abdallat is CEO of Beyond AI. He has over 20 years of management experience in the fields of artificial intelligence, sensors, instruments, devices and software for telecommunications, life sciences, environmental monitoring, process...
SYS-CON Events announced today that Ericsson has been named “Gold Sponsor” of SYS-CON's @ThingsExpo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. Ericsson is a world leader in the rapidly changing environment of communications technology – providing equipment, software and services to enable transformation through mobility. Some 40 percent of global mobile traffic runs through networks we have supplied. More than 1 billion subscribers around the world re...
There is an ever-growing explosion of new devices that are connected to the Internet using “cloud” solutions. This rapid growth is creating a massive new demand for efficient access to data. And it’s not just about connecting to that data anymore. This new demand is bringing new issues and challenges and it is important for companies to scale for the coming growth. And with that scaling comes the need for greater security, gathering and data analysis, storage, connectivity and, of course, the...
SYS-CON Events announced today that DatacenterDynamics has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY. DatacenterDynamics is a brand of DCD Group, a global B2B media and publishing company that develops products to help senior professionals in the world's most ICT dependent organizations make risk-based infrastructure and capacity decisions.
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, will discuss how research has demonstrated the value of Machine Learning in delivering next generation analytics to im...
This is not a small hotel event. It is also not a big vendor party where politicians and entertainers are more important than real content. This is Cloud Expo, the world's longest-running conference and exhibition focused on Cloud Computing and all that it entails. If you want serious presentations and valuable insight about Cloud Computing for three straight days, then register now for Cloud Expo.