WebObjects

From Example Problems
Jump to: navigation, search

Template:Infobox Software WebObjects is a Java Web application server by Apple Computer which is available, at no additional cost, as part of the company's Mac OS X platfom. It has a range of tools and frameworks to develop and deploy Web applications and Web services. Its hallmark features are its deep object-orientation, powerful data connectivity features and rapid prototyping tools. Applications created with WebObjects can be Web browser-based, have the full interactivity of stand-alone Java desktop applications or be offered as standards-based Web services.

Originally released by NeXT Software in March 1996, WebObjects was the world's first object-oriented Web application server. The time and cost benefits of 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 Computer in 1997, WebObjects' profile has languished in the marketplace. With many early adopters having since switched to alternative technologies, Apple is itself now the biggest client for WebObjects, relying on it to power its Apple Store, .Mac online services and the iTunes Music Store — WebObjects' most high-profile implementation to date.

The WebObjects development tools and frameworks are part of the install package for Apple's free Xcode IDE for Mac OS X, and the deployment runtime and license are included with Mac OS X Server (from $499, or included with Apple's Xserve hardware).

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 (provided they purchase a copy of Mac OS X Server to obtain the necessary deployment license). You can use the included WebObjects J2SE application server or deploy on third-party J2EE application servers such as JBoss, Apache Tomcat, BEA WebLogic or IBM WebSphere.

To ease the transition to a Mac OS X-only 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.

What Is WebObjects?

  • A collection of proprietary frameworks: WebObjects comes with a rich, mature collection of proprietary Java frameworks that provide the functionality common to most Web applications;
  • A set of Web application development tools: WebObjects uses the Xcode IDE for Mac OS X, along with WebObjects-specific tools such as WebObjects Builder and EOModeler;
  • A Web application server: WebObjects includes a stand-alone, J2SE-based Web application server with a Web-based administration tool called JavaMonitor. Applications can also be deployed using the open-source, industry standard JBoss;
  • Rules-Based Rapid Application Development: Given a data model, WebObjects can automatically create a customizable Web application without writing a single line of code.

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 (both runtime software and an unlimited license) has been included with Apple's OS X Server since May 2001.

With the release of version 5.3 in June 2005, WebObjects fully transitioned from a stand-alone product to an integral part of the Mac OS X platform. The developer tools and frameworks, which previously sold for $699, were now bundled free with Apple's Xcode IDE. The corollary of this move was that support for other platforms, such as Windows, was discontinued.

Apple has said it will further integrate WebObjects development tools with Xcode in future releases.

Advantages of WebObjects

WebObjects has a number of key technologies that give it a significant advantage over other application servers:

  • Zero Cost to Mac Developers: The tools and frameworks required to develop and deploy WebObjects applications are free for users of Mac OS X and Mac OS X Server.
  • 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 (although you must have Mac OS X Server in order to get a license key);
  • Scalability and Performance: You can run multiple instances of your 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 you to rapidly create an HTML-based Web application that accesses a database.
  • Direct To Java Client allows you 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 you 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 leverages 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 J2EE-compatible application server such as JBoss.
  • J2EE integration: WebObjects applications can be packaged in a single directory (an exploded .war file) that make it easier to deploy to a J2EE 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.

WebObjects version history

WebObjects was originally released by NeXT Computer in March 1996, but was acquired by Apple Computer when Apple bought NeXT in December of that year.

  • 1.0 — March 28, 1996
    • Debut release.
  • 2.0 — June 25, 1996
    • Pre-release version of WebObjects Builder application.
  • 3.0November 1996
  • 3.1
    • Supports a subset of the Java APIs.
  • 3.5December 1997
    • Enhanced Java support: all objects and components can be worked on as a set of Java APIs based on a complete implementation of the JDK 1.1.3.
  • 4.0September 1998
    • First version of WebObjects to run on the Mac platform — specifically Mac OS X Server 1.0 (a public release of the beta OS formerly code-named 'Rhapsody').
    • OPENSTEP 4.2 OS no longer supported; Windows NT now uses a new version of the OpenStep base of libraries and binary support called Yellow Box.
    • Direct actions introduced whereby actions can be sent directly to an object that can handle it, allowing for simpler, static URLs.
    • Direct to Web code-free development assistant introduced.
    • WebObjects and Enterprise Objects Framework provide thread-safe APIs. This means that you can write a multithreaded WebObjects application where you couldn't before. This enables applications that can provide user feedback for long-running requests.
    • Better tools for managing, configuring and testing the scalability of applications.
    • Java capabilities are greatly improved over previous version, however compiled Objective-C is still two to three times faster;
    • Possible to build a fully capable Java client either as a stand-alone app or as an applet with the Interface Builder - all sorts of Swing and Java Bean components are sitting on IB palettes for wiring up.
    • Developers can now debug applications on a machine that doesn't have a web server present.
    • EOF 3.0 adds support for a new database, OpenBase Lite, which ships with EOF 3.0 as an unsupported demo.
    • EOF 3.0 introduces new API, mainly in EOUtilities, to facilitate common programming tasks.
    • EOModeler adds support for prototype attributes and the ability to create and store complex queries (or EOFetchSpecifications).
  • 4.5March 2000
    • Last version which supported the Objective-C API.
    • Integrated XML support using IBM's alphaWorks parser.
    • New WebObjects Builder interface, specifically in the main window toolbar, the user interface for binding keys, and the table editing user interface. A path view, an API editor, and component validation have been added.
    • Application profiling tools.
    • EOF 4.5 comes with a new sample adaptor: the LDAP adaptor.
    • Direct to Web now allows you to create your own visual style and exposes a great deal of new API.
    • Java Client extended considerably, including a nbew user interface generation layer, Direct to Java Client.
  • 5.0May 2001
    • Major rewrite from Objective-C to Java.
  • 5.1 — January 10, 2002
    • Create and deploy Enterprise JavaBeans using the built-in container based on OpenEJB.
    • Deploy WebObjects applications as JSPs or Servlets on top of third-party application servers.
    • Access and manipulate data stored in JNDI or LDAP directory services.
    • Automatically generate desktop Java client applications with rich, interactive user interfaces.
    • Leverage the WebObjects template engine and object-relational mapping for seamless XML messaging.
  • 5.2November 2002
    • Web Services support.
    • Improvements to J2EE integration
    • Java Web Start support.
    • Improvements to robustness and stability of Enterprise Objects.
    • Major bug fixes led many developers to hail this as the first stable 5.x release of WebObjects.
  • 5.2.1 — November 2002
    • Resolved some incompatibilities with the latest Java 1.4.1 implementation for Mac OS X.
  • 5.2.2 — August 2003
    • Compatibility with Mac OS X 10.3 Panther and the Xcode IDE.
    • JBoss on Panther Server qualification.
    • Qualified for Java 1.4.1.
    • Fixes for EOF runtime and WOFileUpload.
  • 5.2.3 — February 2004
    • Performance and stability update addressing issues with CLOSE_WAIT states in deployment using JavaMonitor and wotaskd and issues related to EOF under high load.
    • Qualified for Java 1.4.2.
  • 5.2.4 — May 2, 2005
  • 5.3 (developer) for Mac OS X 10.4 — June 6, 2005
    • WebObjects developer tools included free with the Xcode IDE (v2.1).
    • Development and deployment on platforms other than Mac OS X no longer supported by Apple.
    • EOModels can be created and edited within Xcode with a new EOModeler plugin that integrates with the CoreData modeling tools.
    • WebObjects Builder has UI enhancements and generates HTML 4.0.1 code.
    • WebObjects runtime now supports HTML 4.0.1.
    • NSArray, NSDictionary and NSSet now implement the java.util.Collection interfaces.
    • Axis 1.1 integrated with the Direct To WebServices feature.
    • WebObjects is qualified against Oracle 10g using the 10.1.0.2 JDBC drivers; Microsoft SQL Server 2000 8.00.194; MySQL 4.1.10a; OpenBase 8.0; Oracle 9i Enterprise Edition Sybase ASE 12.5
  • 5.3 (deployment) for Mac OS X Server 10.4 — June 23, 2005
    • Installer updates the Application Server components in Mac OS X Server 10.4 to WebObjects 5.3.
  • 5.3.1 — November 10, 2005
    • Adds a modified Developer tools license that allows WebObjects applications developed with Xcode 2.2 to be deployed on any compatible platform.
    • Adds better SQL Generation in the EOModeler Plug-in design tool in Xcode.
    • Improved FetchSpecification building in the EOModeler Plugin design tool in Xcode.
    • Adds a "components and elements" window for improved workflow in WebObjects Builder.
    • Addresses incompatibilities with Xcode 2.2 Developer tools on Mac OS X 10.4.
    • Bug fixes.

OpenSource alternatives

With the move of WebObjects from Objective-C (last version WO 4.5.1) to Java (first version WO 5.0), people's interest grew in OpenSource alternatives to WebObjects which kept using the Objective-C language. The two frameworks available are SOPE which is used as the basis of the OpenGroupware.org groupware server for about eight years, and GNUstep-web, which is part of the GNUstep project.

There are Java-based alternatives, also. Apache Tapestry has a similar design and philosophy with WebObjects. There are areas in which it clearly outclasses WO: its templating system is far more powerful; it doesn't rely on Apple's somewhat-obscure and proprietary NS framework; and it allows much more flexibility with packages than WebObjects. However, in some ways it is more quirky - page-level caching is straightforward in WebObjects but something of a minefield in Tapestry. Also, tapestry is a less stable platform: the next major release will involve significant changes affecting users whereas WebObjects hasn't undergone a major upgrade for several years.

Tapestry is frequently combined with Cayenne, a persistence framework inspired by EOF. Again, there are notable differences. Cayenne does not offer nested editing contexts. However, it does allow developers to un-insert objects from contexts (a feature often missed in EOF). Also, Cayenne is much less wordy than EOF, which is notorious for making the developer deal with methods like addObjectToBothSidesOfRelationshipWithKey(Object, Object). Again, Cayenne is evolving rapidly. The upcoming 1.2 release is expected to be a significant change from 1.1 and this will incurr maintenance.

Well Known Sites Using WebObjects


External links

Information and code examples

Alternative Development Platforms

Mailing Lists

Open Source Alternatives

fr:WebObjects it:WebObjects pl:WebObjects ja:WebObjects