Artigo: What is Middleware and What Are The Business Implications of Its Use?

Fala Pessoal,

       Encontrei um site muito legal, www.cio.com, pelo que percebi ele é um concentrador de artigos, apesar de ser voltado mais para a área de negocios, ele apenas fala de assuntos relacionados a TI.

       Achei um artigo sobre Middleware muito bom, aconselho a leitura.

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What is Middleware and What Are
The Business Implications of Its Use?

Basically, it's the technology version of us all just getting along.

BY WILLIAM WHITE

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MIDDLEWARE IS ONE of the most overused and least understood terms in IT. As Bill Gates testified in the Microsoft antitrust trial, "It's a term of such ambiguity, you wouldn't find me using it outside of the lawsuit."

The objective of middleware is to allow communications between applications that were not originally designed to work with each other and may be running on different platforms. This is accomplished by removing selected tasks from an application and embedding them into separate modules or layers that are independent of the application and network location. The benefits to IT organizations are that middleware:

• allows the separation of business logic from the data, thus multiple applications can access common data;
  
  
• allows the separation of common business logic onto separate platforms, thus enabling network transparency;
  
  
• isolates the communication mechanisms between applications and data or applications and server-based modules.

Middleware has become very complex and sophisticated over the last 20 years; and in the last five years, its diversity has doubled as the Internet has moved to the forefront of application development. (According to Gartner, the worldwide application integration, middleware and portal markets will grow from $5.1 billion in 2001 to $10.5 billion by 2006; InternetWeek 6/25/2002).

Middleware is defined as software programs that provide an abstraction capability enabling applications to focus on the business logic vs. how and where underlying services are performed. For example, when an application issues an SQL statement requesting data from a database, the application does not need to know where the SQL call goes or how it is processed, only that it returned the requested data.


Why Embrace Middleware?
Given the complexity and variety of solutions offered by the vendor community, why should you embrace middleware? The world of IT mirrors the external world very closely in terms of the degree of interrelationships required between companies, organizations and their systems. In that regard, you have to find ways for information and associated business processes to be compatible with each other. Systems become very complex and as new systems are added, they usually must speak to each other and operate seamlessly.

When companies merge or acquire others, one of the biggest challenges is to integrate those disparate systems. Direct connections can be built between systems, but IT organizations rarely have the time to build custom linkages. The solution is ? middleware.

Development teams have used middleware for years in various degrees ? mostly in single applications ? to reduce the amount of code and time invested to deliver the required business functionalities. Today, applications must be designed to facilitate rapid reorganization as a business shifts to address new markets, channels and competition.

Middleware can be loosely segmented into the following four categories.

Object- and Component-Oriented Middleware
The premise of J2EE, .NET, CORBA and ORBs is to facilitate the reuse of components independent of the higher-level application. J2EE (Sun Microsystems) and .NET (Microsoft) are two complete platforms that provide an entire application architecture, including the middleware components, while CORBA and ORBs are architectures describing object-oriented process interactions over a network.

Using prebuilt components has two benefits:

1. It drastically reduces development time by leveraging past projects and using code libraries.
2. It cuts time to market dramatically by developing reusable components.

Most IT shops today are moving away from pure object-oriented middleware due to significant implementation and manageability issues. More promising are Web services that are just starting to be implemented.

Message-Oriented Middleware
Message-oriented middleware is one of the most commonly used middleware categories. In the first model, "publish and subscribe," an application can "publish" information, but it is up to the receiving application to "subscribe." In other words, a receiving application can be as simple as a warehouse reorder module that has subscribed to the warehouse inventory module and is interested in quantities on hand.

E-mail is a message-oriented middleware service. The e-mail application is only concerned with the message content and the delivery address. Middleware takes care of delivering the message. Models that are more sophisticated provide additional controls and capabilities. The second model is "message queuing" which is a much richer environment than regular e-mail. In this model, "messages" can be routed to multiple locations and the middleware can guarantee their delivery. In other words, the receiving application accepts the message and indicates that it is satisfactory. IBM's MQSeries is a prime example of such a product.

Web-Based Middleware
The Web-based realm of browsers, Web servers, etc., is commonplace for all IT organizations and many applications now have a Web browser as their only user interface.

The current trend is to use XML to move data between applications. XML is a language that defines a syntax and document organization for data, both containing human and machine-readable tag/value pairs. Many of the application integration middleware products use XML as the data exchange protocol; and in the B2B space, XML will be the dominant method of data exchange in the future, eventually replacing electronic data interchange (EDI). Web-based middleware is quickly evolving from its emerging new technology status, into a mainstream, complete application framework.

Application Integration Middleware
This area has seen an explosion of growth over the last five years. Some of the different types of application integration middleware are discussed below.

Screen Scraping: This is one of the oldest and simplest forms of application integration. Simply, it is "reading" the character stream that is displayed on a terminal screen and using that information within the context of a separate application. Although this is widely used in many IT organizations because it can be implemented quickly, the big problem with screen scraping occurs when the "scraped" system changes, which renders the "reading" system inaccurate or unusable. Correcting this problem is costly.

Database Gateways: Database gateways act as interface translators that move data, SQL commands and applications from one type of database to another. They must know the details (syntax, data format, data types and catalog naming conventions) of the products to be accessed and synchronized with software releases of the data sources. The price of this accessibility is speed, because it is necessary to translate the client request and the server results. The client, gateway and server can reside on the same platform or different ones. This allows gateways to connect clients and servers running on dissimilar networks. They are ideally suited to bridge network protocols, such as TCP/IP, OSI and SNA, while acting as the transportation interfaces for moving data among database platforms. Database gateways have the following functions: (1) accept statements specified by a well-defined grammar (usually SQL) from a client application, (2) translate the statements to a specific database format, (3) send the statements to be executed against the database, (4) translate the results back into a well-defined format, and (5) return the data and status information to the client.

Enterprise Application Integration (EAI): EAI technologies are an amalgamation of communications/messaging, XML, data transformation, brokers, process models and development frameworks. This "all-in-one" approach is usually provided by vendors who specialize in this particular technology. While the breadth of EAI technologies may appear to be daunting, the basic premise of this category is straightforward.

The high-level view of EAI is to enable a very intelligent layer of software to be the intermediary between dissimilar applications. For example, assume that a critical IT project will allow data to flow between two dissimilar manufacturing systems, such as SAP and Baan. Both of these packages are very complex and have a number of interfaces that can be utilized. However, the goal is to enable information flow between these two systems and allow for future interconnections. Therefore a more robust solution is often necessary, namely EAI.

Summary
Do not be intimidated by the breadth and complexity of middleware. While this answer cannot cover all of the alternatives, most vendors do a very good job of describing the landscape. Invest time reading the whitepapers from vendors. What appear to be many divergent and competing technologies are variations on a theme. Discover the common themes and you have the keys to understanding. are here to stay. What are the blessings and curses of a dotcom world?

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