Welcome!

Industrial IoT Authors: Elizabeth White, Ed Featherston, Stackify Blog, Yeshim Deniz, SmartBear Blog

Related Topics: Industrial IoT

Industrial IoT: Article

When Should Java And XML Be Used For Messaging?

When Should Java And XML Be Used For Messaging?

When does it make sense to use JMS (Java Message Service) and XML to support a heterogeneous messaging environment? Most buzzword-compliant people talk about JMS and XML when thinking about developing a messaging solution for their organization.

While in most cases this is the correct answer, we need to understand the requirements we're trying to fulfill before giving an answer. For example:

  • Can the solution be deployed using asynchronous communications or does it require synchronous behavior?
  • Will the solution be used in the intranet or extranet?
  • What are the messaging paradigms supported by your system?
  • Does the underlying messaging system support JMS?
  • What qualities of service (QoS) are supported by the messaging system?
  • What are the characteristics of the information to be published on the network?
  • Are e-mail messages a requirement?
  • What are the possible messaging systems the solution will be deploying against?
In short, we need to understand the characteristics of the problem before we can justify the use of any technology - in this case JMS and XML. Let me first give a brief introduction to JMS and explain the role of XML. My goal this month is to help you understand the requirements that XML and JMS are attempting to meet.

JMS
Sun, IBM, Modulus, NEON, OpenHorizon, Oracle, TIBCO, and Vitria developed the JMS specification. The purpose was to define a common API that would enable Java developers to use the same messaging system. In the JMS specification there's a clear distinction between the application and the message provider layers. The software developer is responsible for coding his or her application against the JMS interfaces; the message provider is responsible for coding the implementation to the interfaces. The idea behind this approach is to decouple the client application from the specifics of the messaging system. This allows the message provider layer to plug into the application layer. JMS defines two types of messaging paradigms:

  • Point-to-point
  • Publish/subscribe
The point-to-point paradigm follows a producer/consumer pattern that allows the producer application to write information to a queue and a consumer application to read it from the queue (see Figure 1). The queue mechanism identifies the decoupling point between the producer application and the consumer application. The producer application doesn't depend on the consumer application to access the queue to write to it, or vice versa. Some messaging systems provide QoS that enables persistence of the information stored inside a queue.

The publish/subscribe paradigm follows an observer pattern with explicit interest defined (see Figure 2). This approach allows subscriber applications to specify the types of events they're interested in receiving and allows the publishing application to broadcast messages independent of interested parties. The mapping between interested subscribers and published content is facilitated by the messaging system. This allows subscribers to publish information totally independent of recipients and vice versa. Some messaging systems provide QoS that enables the persistence of published messages for future processing.

JMS developers are responsible for selecting the message provider and for specifying the type of messaging model they want to implement. In addition, some JMS services are supported by the JMS layer independent of the underlying messaging implementation. These are:

  • Transactions
  • Message filtering
These need to be supported by the JMS provider implementation layer, however.

XML
Most messaging systems, including the JMS specification, are agnostic when it comes to message content. They categorize message content as:

  • Basic types (int, float, char, long, etc.)
  • Text (string)
  • Bytes (byte arrays)
This is where XML comes to the rescue by providing the mechanisms to define the content of a message. This information is used by both sender and receiver clients to manipulate complex objects. The XML tags allow the sender application to serialize an object for future consumption by the receiver application. It's the responsibility of the receiver application to reconstruct the object for further manipulation.

Another advantage of using XML for defining the content of a message is that it provides a platform-independent mechanism for exchanging information between heterogeneous applications. This means a Visual Basic application can package an object using XML and send it to a Java application where it can be reconstructed from the XML message.

It's important to realize that XML doesn't provide a communications transport like TIBCO, MQSeries, IIOP, SMTP, and HTTP. However, it can work with any of these transports to provide message- content abstraction. One example of how XML facilitates the creation of communication transport is the use of HTTP and XML to develop XML RPCs.

JMS and XML
Does this mean that the buzzword-compliant people know best? I don't think so! However, they pay enough attention to know what the technologists are saying. As mentioned earlier, JMS provides a communication abstraction layer for messaging while XML provides a message content abstraction layer. JMS enables the use of XML via its TextMessage content type. This enables string-based messages and XML text (see Listing 1).

When JMS and XML?
JMS and XML provide a total abstraction of communications transport and data content. Given this statement, why should you care about any requirements? Isn't this the solution to all your messaging needs? Let's revisit the questions asked earlier:

Q: Can the solution be deployed using asynchronous communications or does it require synchronous behavior?
A: JMS deals with asynchronous communications. If you need to manipulate synchronous flows like RMI, CORBA, or HTTP, you may want to consider using synchronous protocols. While you can implement synchronous behavior with asynchronous protocols, this isn't the norm and it's more difficult.

Q: Will this solution be used in the intranet or extranet?
A: JMS deals with messaging in thje intranet. Publish/subscribe and queue management systems aren't designed to deal with unreliable networks like the Internet. If you want to set up extranet communications, you need to consider XML RPC (SOAP) or SMTP (e-mail).

Q: What are the messaging paradigms supported by your system?
A: Does the underlying system support publish/subscribe or point-to-point? Some systems support only one or the other. Publish/subscribe systems have been optimized for broadcast (e,g., TIBCO). They haven't been optimized for point-to-point. Similarly, queue management systems have been optimized to provide message persistence via queues and point-to-point communications. They haven't been optimized for publish/subscribe.

Q: Does the underlying messaging system support JMS?
A: If your corporate messaging system doesn't support JMS, you may be stuck with their proprietary Java interfaces or you may need to develop your own JNI interfaces.

Q: What QoS are supported by the messaging system?
A: Does the JMS implementation that comes with your messaging system support guaranteed delivery, transactions, and message filtering? If your application requires transactions and your JMS implementation doesn't support them, this may be a problem. You may be forced to evaluate a different JMS provider. If your JMS provider supports message persistence, where is the persistence storage happening, in an RDBMS or proprietary storage? Persistence may be an issue if your JMS provider requires you to purchase a specific RDBMS.

Q: What are the characteristics of the information to be published on the network?
A: If you're using publish/subscribe, what type of information are you publishing? This issue is particularly important if you're using publishing as an event mechanism. Events are normally regarded as lightweight messages. Because of this requirement, it may not make sense to inquire about the overhead of wrapping a simple event value in an XML message. The subscribers may be listening on a topic called shipping orders, and the only content inside the event may be the order number. In this situation there's no need to create an XML message to publish the information. However, if subscribers are listening for the complete order with all of its parameters, it makes sense to package the order object inside an XML message for further processing by the subscriber application.

Q: Are e-mail messages a requirement?
A: JMS doesn't handle e-mail sending or receiving. That's the purpose of the JavaMail APIs. If the application needs to support e-mail for asynchronous messaging, then JMS isn't the answer. However, if your application needs to use an intranet-based messaging system like TIBCO, and you want to implement an e-mail gateway, the combination of JMS and JavaMail is ideal.

Q: What are the possible messaging systems that the solution will be deployed against?
A: If the solution being developed will be used only against one messaging system, it may not make sense to use JMS. This is the case if there's no JMS provider for a particular messaging framework but there is a Java API for that system. However, if the solution can be deployed against multiple messaging systems, it makes sense to leverage a communications abstraction layer.

Conclusion
JMS and XML are an ideal combination and can be deployed to provide a total abstraction solution for messaging and data content. However, you need to understand your requirements clearly before making the technology call. Therefore, it's important to know the limitations and correct usage of the JMS and XML technologies.

More Stories By Israel Hilerio

Israel Hilerio is a program manager at Microsoft in the Windows Workflow Foundation team. He has 15+ years of development experience doing business applications and has a PhD in Computer Science.

Comments (0)

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.


@ThingsExpo Stories
BnkToTheFuture.com is the largest online investment platform for investing in FinTech, Bitcoin and Blockchain companies. We believe the future of finance looks very different from the past and we aim to invest and provide trading opportunities for qualifying investors that want to build a portfolio in the sector in compliance with international financial regulations.
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
Imagine if you will, a retail floor so densely packed with sensors that they can pick up the movements of insects scurrying across a store aisle. Or a component of a piece of factory equipment so well-instrumented that its digital twin provides resolution down to the micrometer.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settle...
Product connectivity goes hand and hand these days with increased use of personal data. New IoT devices are becoming more personalized than ever before. In his session at 22nd Cloud Expo | DXWorld Expo, Nicolas Fierro, CEO of MIMIR Blockchain Solutions, will discuss how in order to protect your data and privacy, IoT applications need to embrace Blockchain technology for a new level of product security never before seen - or needed.
Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
Nordstrom is transforming the way that they do business and the cloud is the key to enabling speed and hyper personalized customer experiences. In his session at 21st Cloud Expo, Ken Schow, VP of Engineering at Nordstrom, discussed some of the key learnings and common pitfalls of large enterprises moving to the cloud. This includes strategies around choosing a cloud provider(s), architecture, and lessons learned. In addition, he covered some of the best practices for structured team migration an...
No hype cycles or predictions of a gazillion things here. IoT is here. You get it. You know your business and have great ideas for a business transformation strategy. What comes next? Time to make it happen. In his session at @ThingsExpo, Jay Mason, an Associate Partner of Analytics, IoT & Cybersecurity at M&S Consulting, presented a step-by-step plan to develop your technology implementation strategy. He also discussed the evaluation of communication standards and IoT messaging protocols, data...
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
In his session at 21st Cloud Expo, Raju Shreewastava, founder of Big Data Trunk, provided a fun and simple way to introduce Machine Leaning to anyone and everyone. He solved a machine learning problem and demonstrated an easy way to be able to do machine learning without even coding. Raju Shreewastava is the founder of Big Data Trunk (www.BigDataTrunk.com), a Big Data Training and consulting firm with offices in the United States. He previously led the data warehouse/business intelligence and B...
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
When shopping for a new data processing platform for IoT solutions, many development teams want to be able to test-drive options before making a choice. Yet when evaluating an IoT solution, it’s simply not feasible to do so at scale with physical devices. Building a sensor simulator is the next best choice; however, generating a realistic simulation at very high TPS with ease of configurability is a formidable challenge. When dealing with multiple application or transport protocols, you would be...
Smart cities have the potential to change our lives at so many levels for citizens: less pollution, reduced parking obstacles, better health, education and more energy savings. Real-time data streaming and the Internet of Things (IoT) possess the power to turn this vision into a reality. However, most organizations today are building their data infrastructure to focus solely on addressing immediate business needs vs. a platform capable of quickly adapting emerging technologies to address future ...
We are given a desktop platform with Java 8 or Java 9 installed and seek to find a way to deploy high-performance Java applications that use Java 3D and/or Jogl without having to run an installer. We are subject to the constraint that the applications be signed and deployed so that they can be run in a trusted environment (i.e., outside of the sandbox). Further, we seek to do this in a way that does not depend on bundling a JRE with our applications, as this makes downloads and installations rat...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
In this strange new world where more and more power is drawn from business technology, companies are effectively straddling two paths on the road to innovation and transformation into digital enterprises. The first path is the heritage trail – with “legacy” technology forming the background. Here, extant technologies are transformed by core IT teams to provide more API-driven approaches. Legacy systems can restrict companies that are transitioning into digital enterprises. To truly become a lead...
Digital Transformation (DX) is not a "one-size-fits all" strategy. Each organization needs to develop its own unique, long-term DX plan. It must do so by realizing that we now live in a data-driven age, and that technologies such as Cloud Computing, Big Data, the IoT, Cognitive Computing, and Blockchain are only tools. In her general session at 21st Cloud Expo, Rebecca Wanta explained how the strategy must focus on DX and include a commitment from top management to create great IT jobs, monitor ...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
The IoT Will Grow: In what might be the most obvious prediction of the decade, the IoT will continue to expand next year, with more and more devices coming online every single day. What isn’t so obvious about this prediction: where that growth will occur. The retail, healthcare, and industrial/supply chain industries will likely see the greatest growth. Forrester Research has predicted the IoT will become “the backbone” of customer value as it continues to grow. It is no surprise that retail is ...