04
Mon, Nov
6 New Articles

Distributed Components: EJBs, CORBA, and COM

General
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

The architectures for distributed software components have grown up quite considerably in the last six months. Today we have three competing distributed component models: Sun’s Enterprise JavaBeans (EJBs), Object Management Group’s (OMG) Common Object Request Broker (CORBA), and Microsoft’s Common Object Model (COM). A year ago, EJBs were receiving all the trade press. EJBs weren’t Microsoft-specific, and they provided a rather complete architecture for business programming. Recently, however, Microsoft and OMG have enhanced their component models so that they are extremely competitive with EJBs.

What Are Distributed Components, and Why Do I Need Them?

For years many IT departments have been handling the distribution of data between multiple platforms with a fly-by-the-seat-of-the-pants approach. They have been downloading complete data files to PCs so accountants can massage data with their spreadsheets and business managers can play programmer with their Access and FoxPro applications. It’s not an issue of sending the data down to these applications; the issue is when you have to update your database with the manipulations of these homegrown, uncontrolled applications. The power of SQL with ODBC and, more recently, Java Database Connectivity (JDBC) has allowed Visual Basic and Java developers to have direct access to the database of your AS/400. The architecture of these applications could be construed as an improvement because there is no need to download complete files and then laboriously merge changes back in. But do those applications maintain the same integrity with your database as your core application code?

The architecture of distributed components allows you to build a standard interface for host-based application code. Client applications no longer contain code that directly manipulates host-based data. Instead, a client app receives a handle (a remote reference) to one of the standard interfaces of your host application. That interface consists of a set of functions. Some functions are used to retrieve information, and others are subsequently used to modify the retrieved data. When the client invokes a function of that interface, the code of that function executes on the host. The point is that, with distributed components, all access to your corporate database is through the standard interface. Thus, distributed component models enhance control of your application’s data by providing a consistent interface. No longer do you deliver data files, and no longer do you distribute code. Now you deliver APIs to host-based code.


The Model Walk

The architecture of distributed components is very attractive, but which of the three models do you choose: EJBs, CORBA, or COM? CORBA is a cross-platform and language- neutral model. If the distributed components of your n-tier application are to be accessed on non-Microsoft operating systems and by languages other than Java, CORBA is the answer. Microsoft’s COM, although its architecture could be implemented on any platform, is Microsoft-operating-system-specific. But COM is language-independent. One reason for COM’s success is that its implementation is included with every copy of Microsoft Windows. Internet Information Server (IIS), which is bundled with NT, also has integrated support for COM. If you decide to use CORBA or EJBs, you’ll have to buy a Web application server that supports that model. There are plenty of Web application servers to choose from, but, when you add up the additional costs, COM may look more appealing.

EJBs are language-specific but platform-independent. Until recently, EJBs provided the most complete architecture for business components. The engine behind EJBs (provided by a Web application server) handles such things as the mapping of relational data to business components, database concurrency, and load balancing. EJBs may be language-specific, but because the low-level protocol of EJBs is the same as CORBA’s, non-Java client applications can access EJB components.

COM+ and CORBA Now

Microsoft and OMG have enhanced their component models to be even more competitive with EJBs. The new version of COM, called COM+, integrates the features of Microsoft Transaction Server (MTS), Microsoft Message Queuing (MSMQ), IIS, and In-Memory Database (IMDB) along with other services. The new version of CORBA, CORBA CCM (for CORBA Component Model), is a superset of Sun’s EJB specification.

I believe that Microsoft’s COM+ is an excellent choice because of its high integration with Microsoft Windows, but, if you plan to deploy on any other OS, then you need to look at CORBA CCM or EJBs. CORBA CCM is now a more complete specification than EJBs, and CORBA is language-independent. But there are not as many tools available for CORBA, the tools are more expensive, and CORBA is decidedly more complex than EJBs. Your choice, then, depends on the platforms you intend to deploy on and the programming language(s) you plan to support.


Don Denoncourt

Don Denoncourt is a freelance consultant. He can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..


MC Press books written by Don Denoncourt available now on the MC Press Bookstore.

Java Application Strategies for iSeries and AS/400 Java Application Strategies for iSeries and AS/400
Explore the realities of using Java to develop real-world OS/400 applications.
List Price $89.00

Now On Sale

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: