Welcome!

XML Authors: Lori MacVittie, Carmen Gonzalez, Pat Romanski, Peter Silva, Colin Lacey

Related Topics: XML

XML: 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
The Internet of Things (IoT) is making everything it touches smarter – smart devices, smart cars and smart cities. And lucky us, we’re just beginning to reap the benefits as we work toward a networked society. However, this technology-driven innovation is impacting more than just individuals. The IoT has an environmental impact as well, which brings us to the theme of this month’s #IoTuesday Twitter chat. The ability to remove inefficiencies through connected objects is driving change throughout every sector, including waste management. BigBelly Solar, located just outside of Boston, is trans...

SUNNYVALE, Calif., Oct. 20, 2014 /PRNewswire/ -- Spansion Inc. (NYSE: CODE), a global leader in embedded systems, today added 96 new products to the Spansion® FM4 Family of flexible microcontrollers (MCUs). Based on the ARM® Cortex®-M4F core, the new MCUs boast a 200 MHz operating frequency and support a diverse set of on-chip peripherals for enhanced human machine interfaces (HMIs) and machine-to-machine (M2M) communications. The rich set of periphera...

SYS-CON Events announced today that Matrix.org has been named “Silver Sponsor” of Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Matrix is an ambitious new open standard for open, distributed, real-time communication over IP. It defines a new approach for interoperable Instant Messaging and VoIP based on pragmatic HTTP APIs and WebRTC, and provides open source reference implementations to showcase and bootstrap the new standard. Our focus is on simplicity, security, and supporting the fullest feature set.
Predicted by Gartner to add $1.9 trillion to the global economy by 2020, the Internet of Everything (IoE) is based on the idea that devices, systems and services will connect in simple, transparent ways, enabling seamless interactions among devices across brands and sectors. As this vision unfolds, it is clear that no single company can accomplish the level of interoperability required to support the horizontal aspects of the IoE. The AllSeen Alliance, announced in December 2013, was formed with the goal to advance IoE adoption and innovation in the connected home, healthcare, education, aut...
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...
The only place to be June 9-11 is Cloud Expo & @ThingsExpo 2015 East at the Javits Center in New York City. Join us there as delegates from all over the world come to listen to and engage with speakers & sponsors from the leading Cloud Computing, IoT & Big Data companies. Cloud Expo & @ThingsExpo are the leading events covering the booming market of Cloud Computing, IoT & Big Data for the enterprise. Speakers from all over the world will be hand-picked for their ability to explore the economic strategies that utility/cloud computing provides. Whether public, private, or in a hybrid form, clo...
Software AG helps organizations transform into Digital Enterprises, so they can differentiate from competitors and better engage customers, partners and employees. Using the Software AG Suite, companies can close the gap between business and IT to create digital systems of differentiation that drive front-line agility. We offer four on-ramps to the Digital Enterprise: alignment through collaborative process analysis; transformation through portfolio management; agility through process automation and integration; and visibility through intelligent business operations and big data.
The Transparent Cloud-computing Consortium (abbreviation: T-Cloud Consortium) will conduct research activities into changes in the computing model as a result of collaboration between "device" and "cloud" and the creation of new value and markets through organic data processing High speed and high quality networks, and dramatic improvements in computer processing capabilities, have greatly changed the nature of applications and made the storing and processing of data on the network commonplace.
Be Among the First 100 to Attend & Receive a Smart Beacon. The Physical Web is an open web project within the Chrome team at Google. Scott Jenson leads a team that is working to leverage the scalability and openness of the web to talk to smart devices. The Physical Web uses bluetooth low energy beacons to broadcast an URL wirelessly using an open protocol. Nearby devices can find all URLs in the room, rank them and let the user pick one from a list. Each device is, in effect, a gateway to a web page. This unlocks entirely new use cases so devices can offer tiny bits of information or simple i...
Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, will address the big issues involving these technologies and, more important, the results they will achieve. How important are public, private, and hybrid cloud to the enterprise? How does one define Big Data? And how is the IoT tying all this together?
The Internet of Things (IoT) is going to require a new way of thinking and of developing software for speed, security and innovation. This requires IT leaders to balance business as usual while anticipating for the next market and technology trends. Cloud provides the right IT asset portfolio to help today’s IT leaders manage the old and prepare for the new. Today the cloud conversation is evolving from private and public to hybrid. This session will provide use cases and insights to reinforce the value of the network in helping organizations to maximize their company’s cloud experience.
TechCrunch reported that "Berlin-based relayr, maker of the WunderBar, an Internet of Things (IoT) hardware dev kit which resembles a chunky chocolate bar, has closed a $2.3 million seed round, from unnamed U.S. and Switzerland-based investors. The startup had previously raised a €250,000 friend and family round, and had been on track to close a €500,000 seed earlier this year — but received a higher funding offer from a different set of investors, which is the $2.3M round it’s reporting."
The Industrial Internet revolution is now underway, enabled by connected machines and billions of devices that communicate and collaborate. The massive amounts of Big Data requiring real-time analysis is flooding legacy IT systems and giving way to cloud environments that can handle the unpredictable workloads. Yet many barriers remain until we can fully realize the opportunities and benefits from the convergence of machines and devices with Big Data and the cloud, including interoperability, data security and privacy.
All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. Over the summer Gartner released its much anticipated annual Hype Cycle report and the big news is that Internet of Things has now replaced Big Data as the most hyped technology. Indeed, we're hearing more and more about this fascinating new technological paradigm. Every other IT news item seems to be about IoT and its implications on the future of digital busines...
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
The Internet of Things needs an entirely new security model, or does it? Can we save some old and tested controls for the latest emerging and different technology environments? In his session at Internet of @ThingsExpo, Davi Ottenheimer, EMC Senior Director of Trust, will review hands-on lessons with IoT devices and reveal privacy options and a new risk balance you might not expect.
IoT is still a vague buzzword for many people. In his session at Internet of @ThingsExpo, Mike Kavis, Vice President & Principal Cloud Architect at Cloud Technology Partners, will discuss the business value of IoT that goes far beyond the general public's perception that IoT is all about wearables and home consumer services. The presentation will also discuss how IoT is perceived by investors and how venture capitalist access this space. Other topics to discuss are barriers to success, what is new, what is old, and what the future may hold.
Swiss innovators dizmo Inc. launches its ground-breaking software, which turns any digital surface into an immersive platform. The dizmo platform seamlessly connects digital and physical objects in the home and at the workplace. Dizmo breaks down traditional boundaries between device, operating systems, apps and software, transforming the way users work, play and live. It supports orchestration and collaboration in an unparalleled way enabling any data to instantaneously be accessed on any surface, anywhere and made interactive. Dizmo brings fantasies as seen in Sci-fi movies such as Iro...
There’s Big Data, then there’s really Big Data from the Internet of Things. IoT is evolving to include many data possibilities like new types of event, log and network data. The volumes are enormous, generating tens of billions of logs per day, which raise data challenges. Early IoT deployments are relying heavily on both the cloud and managed service providers to navigate these challenges. In her session at 6th Big Data Expo®, Hannah Smalltree, Director at Treasure Data, to discuss how IoT, Big Data and deployments are processing massive data volumes from wearables, utilities and other mach...
This Internet of Nouns trend is still in the early stages and many of our already connected gadgets do provide human benefits over the typical infotainment. Internet of Things or IoT. You know, where everyday objects have software, chips, and sensors to capture data and report back. Household items like refrigerators, toilets and thermostats along with clothing, cars and soon, the entire home will be connected. Many of these devices provide actionable data - or just fun entertainment - so people can make decisions about whatever is being monitored. It can also help save lives.