WebObjects
WebObjects is a Java web application server from Apple Inc., and a web application framework that runs on the server. It is available, at no additional cost, as part of the Xcode Developer Tools included with Apple’s Mac OS X operating system. Its hallmark features are its deep object-orientation, powerful database connectivity, and rapid prototyping tools. Applications created with WebObjects can be deployed as web sites, Java Web Start desktop applications, and/or standards-based web services.
WebObjects was created by NeXT Software, Inc., and was released to the public in March 1996. The time and cost benefits of rapid, object-oriented development attracted major corporations to WebObjects in the early days of e-commerce, with clients including Disney, Dell Computer, and BBC News. However, following NeXT’s merger into Apple Inc. in 1997, WebObjects’ public profile has languished in the marketplace. With many early adopters having since switched to alternative technologies, Apple is now the biggest client for WebObjects, relying on it to power its online Apple Store, MobileMe online services, and the iTunes Store — WebObjects’ highest-profile implementation to date.
Despite the drop in interest, Apple has continued to grow and improve WebObjects, announcing a renewed commitment to the product and its developer base at their World Wide Developer’s Conference in June 2007. The WebObjects development tools and frameworks are now a part of the install package for Apple’s free Xcode IDE for Mac OS X, and the deployment runtime is included with Mac OS X Server. WebObjects license keys are also a thing of the past, allowing development and unlimited deployment capabilities right out of the box.
While WebObjects is supported only on the Mac OS X platform, the deployment runtime is, nonetheless, pure Java and Apple allows users to deploy WebObjects applications on any platform which supports Java. You can use the included WebObjects Java SE application server or deploy on third-party Java EE application servers such as JBoss, Apache Tomcat, WebLogic Server or IBM WebSphere.
To ease the transition to a Mac OS X-only development solution, Apple continues to sell the earlier version 5.2, which includes development tools for Windows 2000 Professional and official deployment support for Windows 2000 Server and Solaris 8.
Tools
As of 2008 most WebObjects architects and engineers are using the tools being developed by the WebObjects community. These tools run within the Eclipse IDE and are open-source. The WebObjects plug-ins for Eclipse are known as WOLips.
Building WebObjects frameworks and applications for deployment is typically achieved using the WOProject set of tools for ant or maven. These tools are distributed with WOLips.
History of WebObjects
Under Apple’s ownership WebObjects has aligned more closely with the company’s corporate strategy of using software to drive hardware sales. In 2000, the price was dramatically slashed from $50,000 (for the full deployment license) to $699. WebObjects has been included with Mac OS X Server since May 2001, and no longer requires a license key for development or deployment.
2005: WebObjects is bundled with Mac OS X
WebObjects fully transitioned from a stand-alone product to an integral part of the Mac OS X platform with the release of version 5.3 in June 2005. The developer tools and frameworks, which previously sold for US$699, were now bundled with Apple’s Xcode IDE. The corollary of this move was that support for other platforms, such as Windows, was discontinued.
Apple said that it would further integrate WebObjects development tools with Xcode in future releases. This included a new EOModeler Plugin for Xcode. This strategy, however, was soon altered.
2006: Apple deprecates WebObjects developer tools
Apple announced the deprecation of Mac OS X’s Cocoa-Java bridge with the release of Xcode 2.4 at the August 2006 Worldwide Developers Conference and, with it, all dependent features, including the entire suite of WebObjects developer applications — EOModeler, EOModeler Plugin, WebObjects Builder, WebServices Assistant, RuleEditor and WOALauncher.
Apple had decided to concentrate its engineering resources on the runtime engine of WebObjects, leaving the future responsibility for developer applications with the open source community. The main open source alternative — the Eclipse IDE with the WOLips suite of plugins — had matured to such an extent that its capabilities had, in many areas, surpassed those of Apple’s own tools, which had not seen significant updates for a number of years.
Apple promised to provide assistance to the community in its efforts to extend such tools and develop new ones. In a posting to the webobjects-dev mailing list Daryl Lee from Apple’s WebObjects team publicly disclosed the company’s new strategy for WebObjects. It promised, in short, to “make WebObjects the best server-side runtime environment” by:
Improving performance, manageability, and standards complianceMaking WebObjects work well with ANT and the most popular IDEs, including Xcode and EclipseOpening and making public all standards and formats that WebObjects depends upon
2007: License key no longer required
WebObjects 5.4, which shipped with Mac OS X Leopard in October 2007, eliminated the license key requirement for both development and deployment of WebObjects applications on all platforms. All methods for checking license limitations were deprecated.
2009: No longer supported
In the MacOS X 10.6 Snow Leopard Server manual, Apple is stating that WebObjects is no longer supported. On the other side, this doesn’t mean development has been stopped, but more likely that Apple doesn’t want to bear support costs.
Advantages of WebObjects
WebObjects has a number of key technologies that differentiate it from some application servers:
Zero Cost: The tools and frameworks required to develop and deploy WebObjects applications are free-of-charge.Streamlined Database Access: Database tables are represented in WebObjects as collections of Java classes called Enterprise Objects. The developer creates a “model” that maps objects to database rows. This high level of abstraction relieves developers from the drudgery of writing inflexible, database-specific code. With the use of drivers, such as JDBC, WebObjects automatically handles the writing of appropriate SQL code.Separation of Presentation Logic, Business Logic, and Data: WebObjects conforms to the MVC programming paradigm, enforcing a clean separation of presentation (Web pages), logic (Java code) and data (data store).State Management: Without using cookies, WebObjects provides objects that allow you to maintain information for the life of a particular user session, or longer.Pure Java: WebObjects applications are 100% Pure Java, which means they can be deployed on any platform with a certified Java 2 virtual machine.Scalability and Performance: Administrators run multiple instances of an application, either on one or on multiple application servers. Developers can choose from one of several load-balancing algorithms (or create their own).
Core WebObjects frameworks
A WebObjects application is essentially a server-side executable, created by combining prebuilt application framework objects with the developer’s own custom code. WebObjects’ frameworks can be broken down into three core parts:
The WebObjects Framework (WOF) is at the highest level of the system. It is responsible for the application’s user interface and state management. It uses a template-based approach to take that object graph and turn it into HTML, or other tag-based information display standards, such as XML or SMIL. It provides an environment where you can use and create reusable components. Components are chunks of presentation (HTML) and functionality (Java code) often with a parameter list to enhance reusability. WebObjects Builder is used to create the HTML-templates and creates the .wod-file linking, for instance, a Java String object to interface objects like an input field in a web form.The Enterprise Objects Framework (EOF) is, perhaps, the hallmark feature of WebObjects. EOF communicates with relational databases and turns database rows into an object graph. Using EOModeler the developer can create an abstraction of the database in the forms of Java objects. In order to access or insert information into the database the developer simply accesses the Java Enterprise Objects (EOs) from their business logic. After that EOF manages the Enterprise Objects and automatically creates the required SQL-code to commit the changes to the database.Java Foundation. Both Enterprise Objects and WebObjects rest on the aptly-named Java Foundation classes. This framework contains the fundamental data structure implementations and utilities used throughout the rest of WebObjects. Examples include basic value and collection classes, such as arrays, dictionaries (objects that contain key-value pairs) and formatting classes. Java Foundation is similar to the Foundation framework contained in Apple’s Cocoa API for Mac OS X desktop applications, however Java Foundation is written in Pure Java as opposed to Cocoa’s Objective-C (with its Java bridge runtime wrapper). Foundation classes are prefixed with the letters “NS” (a reference to their NeXTStep OS heritage). Since the transition of WebObjects to Java in 2000, the functionality of many of Apple’s Java Foundation classes is replicated in the Sun’s own JDK. However, they persist largely for reasons of backwards-compatibility and developers are free to use whichever frameworks they prefer.
Rules-Based Rapid Application Development (RBRAD)
WebObjects features a set of rapid development technologies that can automatically create a Web application without the need to write any Java code. Given a model file for a database, WebObjects will create an interface supporting nine common database tasks, including querying, editing and listing. Such applications are useful for prototyping or administering a database, perhaps to check relationships or to seed the database with data.
The user interface is generated dynamically, on-the-fly at runtime using a rules-based system — no code is generated. Consequently, you can modify your application’s configuration at runtime (using an assistant program) without recompiling or relaunching the application.
Developers can utilize one of three different technologies, depending upon the type of interface they wish to employ:
Direct To Web (D2W) allows developers to rapidly create an HTML-based Web application that accesses a database.Direct To Java Client allows developers to rapidly create a client desktop application using the Java Swing toolkit. An advantage of Java Client applications is that they can take advantage of the processing power of the client computer to perform operations such as sorting a list of items received from the server.Direct To Web Services allows developers to rapidly develop Web service-based applications that provide access to a data store.
Advantages of RBRAD
Vastly decreased development and debugging time;Increased stability through the use of highly-exercised code;By using the information contained in the data model file, applications will not violate database integrity. Normally you would have to write code to avoid such situations and handle errors generated by bad data;Fully utilizes the validation services provided by WebObjects and Enterprise Objects.
Java compatibility
WebObjects is a 100% Pure Java solution with the following Java-based features:
Deployment: Applications can be deployed on any operating system that has Java 1.3 or later. Many developers have successfully deployed on Windows and various Linux systems such as Red Hat Linux, Debian and SUSE. Applications can also be hosted on any Java EE compatible application server such as JBoss.Java EE integration: WebObjects applications can be packaged in a single directory (an exploded .war file) that make it easier to deploy to a Java EE servlet container.JDBC: Since WebObjects uses JDBC for database connectivity any DBMS that has a JDBC-driver can be used within WebObjects.Swing interface: WebObjects applications can be delivered to the user as a “Java Client application” or as a Java applet.
WOWODC
Since 2007, the community has held an annual conference for WebObjects developers, WOWODC. In 2007 and 2008, the conference was held the weekend before WWDC, and in 2009, the community promoted two conferences: WOWODC West in San Francisco on June 6 and 7, immediately before WWDC, and WOWODC East in Montreal on August 29 and 30. West is for experienced WebObjects developers, East is for developers who have little or no knowledge of WebObjects.
OpenSource alternatives
Interest in OpenSource alternatives to WebObjects which use the Objective-C language grew with WebObjects’ move from Objective-C (last version WO 4.5.1) to Java (first version WO 5.0). The two frameworks available are SOPE, which has been used as the basis of the OpenGroupware.org groupware server for about eight years, and GNUstepWeb, which is part of the GNUstep project. An open-source rewrite of the EOF framework also exists: AJRDatabase .
There are also Java-based alternatives:
Wotonomy is a project, hosted on Sourceforge, that implements a clean-room, open-source version of the WebObjects 5.x system. It provides a near-complete implementation of the MVC web-framework, as well as partial implementations of Foundation, Control, and Data layers, and other features. It is sufficiently functional for low-transaction volume, single-source database applications. While the project’s structure was re-organized in 2006 around an Apache Maven build infrastructure and migrated to the Subversion revision control system, there has not been any substantial update to the codebase since 2003.
Apache Tapestry has a design and philosophy similar to that of WebObjects. Tapestry is frequently combined with Apache Cayenne, a persistence framework inspired by EOF.